Anatomy and Properties of BambooW. Liese

Institute of Wood Biology and Wood Preservation of the FederalResearch Centre for Forestry and Forest Products,

Leuschnerstr, 91, 2050 Hamburg, Federal Republic of Germany

Abstract

The numerous alternatives in the use ofbamboo depend on the unique properties ofits culm. In order to understand the anatom-ical and chemical make-up and its ensuingmechanical properties, an attempt has beenmade to summarize the accessible informa-tion.

Anatomy

Gross anatomy: The properties of theculm are determined by its anatomical struc-ture. The culm consists of internodes andnodes. At the internodes, the cells are axiallyoriented, whereas at the nodes, cells providethe transverse interconnections. No radial cellelements, such as rays, exist in the inter-nodes. Within the nodes an intensive branch-ing of the vessels occurs. These also bendradially inward and provide transverse con-duction through the nodal diaphragms, sothat all parts of the culm are interwoven. Theouter part of the culm is formed by two epi-dermal cell layers, the inner appearing thickerand highly lignified. The surface of outermostcells are covered by a cutinized layer with awax coating. The inner parts of the culm con-sist of numerous sclerenchyma cells. Anylateral movement of liquids is therefore muchhindered. Pathways for penetration are thusonly the cross ends of the culm and to a muchsmaller extent the sheath scars around thenodes.

The gross anatomical structure of a trans-verse section of any culm internode is deter-mined by the shape, size, arrangement andnumber of the vascular bundles. They areclearly contrasted b y the darker coloredsclerenchymatous tissue against the paren-

chymatous ground tissue. At the peripheralzone of the culm the vascular bundles aresmaller and more numerous, in the innerparts larger and fewer (Figs. 1, 2). Within theculm wall the total number of vascularbundles decreases from bottom towards thetop, while their density increases at the sametime. The culm tissue is mostly parenchymaand the vascular bundles which are com-posed of vessels, sieve tubes with companioncells and fibres. The total culm comprisesabout 50% parenchyma, 40% fibre, and10% conducting tissues (vessels and sievetubes) with some variation according tospecies. The percentage distribution andorientation of cells show a definite patternwithin the culm, both horizontally and ver-tically. Parenchyma and conducting cells aremore frequent in the inner third of the wall,whereas in the outer third the percentage offibers is distinctly higher. In the vertical direc-tion the amount of fibres increases frombottom to top and that of parenchymadecreases (Fig. 3) The common practice ofleaving the upper part of a cut culm unused inthe forest is therefore a waste with regard toits higher fibre content.

Parenchyma: The ground tissue consistsof parenchyma cells, which are mostly ver-tically elongated (100 x 20 urn) with short,cube-like ones interspersed in between. Theformer are characterized by thicker walls witha polylamellate structure (Fig. 4); theybecome Iignified in the early stages of shootgrowth. The shorter cells have a denser cyto-plasm, thinner walls and retain their cyto-plasmic activity for a long time. The functionof these two different types of parenchymacells is still unknown.

Of interest in the structure of parenchymawalls is the occurrence of warts in many taxa

See also recent GTZ publication: Bamboos - Biology, Silvics, Properties, Utilization by Liese, 1985 - Ed,

196

Figure 2. Overview o f 6 culm sec t i on , Dendrocalamus giganteus.

Ftgure 2. Three-dlmenslonal view of culm tissue withvascular bundles.

like Bombusa, Cephalostachyum, Dendro-calamus, Oxytenanthera, Thyrostachys,which have not been observed so far in theparenchyma of hardwoods. Genuine wartshave to be carefully distinguished from cyto-plasmic debris, which are also frequent inparenchyma cells after the death of the proto-plast. Their distribution is variable from verydense to sparse. Among the speciesexamined the parenchyma cells appear topossess a even higher number and density ofwarts than fibres and vessel members.Their size varies from 120 - 520 nm. Theoccurrence of warts in the lignified paren-

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2.10.18.26. 2 10.1826. 2.10.18.26

internodes

parenchyma fi bres

vessels, phloem

Figure 3. Percentage of cell type in the vertical d i rec t i onof a culm;Cephalostachyum perqracile.

chyma cells of bamboo is perhaps an expres-sion of the close association of lignin-likenature of warts, since warts have not beenobserved in non-lignified cells (Parameswaranand Liese, 1977).

Vascular bundles: The vascular bundlein the bamboo culm consists of the xylem withone or two smaller protoxylem elements andtwo large metaxylem vessels (40 - 120 urn)

and the phloem with thinwalled, unlignifiedsieve tubes connected to companion cells(Fig. 5). The vessels possess large diametersin the inner parts of the culm wall and becomesmall towards outside. These water conduct-ing elements have to function throughout thelifetime of a culm without the formation ofany new tissue, as in the case of hardwoodsand softwoods with cambial activity. In olderculms, vessels and sieve tubes can becomepartly impermeable due to depositions of gum-like substances, thus losing their conduc-tivity which may cause death of the agedculms. The one or two tracheary elements ofthe protoxylem have mostly annular thicken-ings. They are local areas of stasis accumulat-

ing wall material, which are connected witheach other by membranes in the early stagesof development. During extension growth ofthe cell, they are disrupted.

The walls of metaxyiem vessels of bam-boo are characterized by a middle lamella anda primary wall together with a well developedzonation of the secondary wall into Sl andS2. Whereas the Sl possesses a flat spiralarrangement of fibrils (90 - 95O) the S2 zoneshows a slight deviation from the known fibrilorientation in tracheids. The fibrils arearranged at an angle of 30 - 90° to the cellaxis; also microlamellae are present withfibrils arranged in a fan-like fashion. This wallstructure perhaps to be considered as“normal”, i s modified In some taxa like Oxy-tenatherd abysinica a n d Melocanna bam-busoides to such an extent that a polylamellaeconstruction results, resembling a paren-chyma wall with the herringbone pattern offibrillar arrangement whereby the number oflayers are mostly restricted to two to four(Parameswaran a n d Liese. 1 9 8 0 ) . W a r t shave been observed in the metaxylem ofvessels of Oxytenanthera nigrociliata, Melo-canna bambusoides. Gigantochloa a l t e r . f.nigra. Schizostachyum blumei. a n d Sbrachycla dium. The pi ts of these vesselstowards the surrounding parenchyma ofadjacent vessel elements are slightly bor-dered. Their membrane consists of fibrils witha net-like texture, resembling hardwood pits,

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Figure 6. Different types of vascular bundles. I: Phyllostachys edulis. I/ Cephalostachyum pergracile.III Oxytonanthcra albociliata, IV: Thyrsostachys oliveri,

199

Of particular interest is also the presenceof a protective layer in the parenchyma cellsadjacent to metaxylem vessels; it consists ofpolysaccharides of the cellulose and hemicel-lulose type without lignification. This observa-tion extends the presence of such a layer tomonocots, besides dicots and softwoods.

Both the metaxylem vessels and thephloem tissue are surrounded by scleren-chyma sheaths. They differ considerably insize, shape and location according to theirposition in the culm and the bamboo species(Grosser and Liese, 1971; 1973; Wu andWang, 1976; Jiang and Li, 1982).

Four to five major types of vascularbundles can be differentiated (cf. Fig. 6).

Type I : consisting ,of one central vascularstrand; supporting tissue only assclerenchyma sheaths;

Type II :

Type III :

Type IV :

Type V :

consisting of one central vascularstrand; supporting tissue only assclerenchyma sheaths; sheath atthe intercellular space (pro-toxylem) strikingly larger than theother three;

consisting-of two parts, the centralvascular strand with sclerenchymasheaths and one isolated fibrebundles;

consisting of three parts, the cen-tral vascular strand with smallsclerenchyma sheaths and twoisolated fibre bundles outside andinside the central strand;

a semi-open type representing afurther link in the evolution ten-dency _

The vascular bundle types and their dis-tribution within the culm correlate with thetaxonomic classification system of Holttum(1956) based on the ovary structure.

For example:

Type I alone :

Type II alone :

Type II and III :

Type III alone :

Arundinaria,Phyllostachys, Fargeria,Sinanundinaria

Cephalostachyum,Pleioblastus

Melocanna,Schizostachyum

Oxytenanthera

Type III and IV : Bambusa,Dendrocalamus.Gigantochloa. Sinoclamus

Leptomorph genera have only the vascu-lar bundle type I, whereas pachymorphgenera possess types II, III and IV. Size andshape of the vascular bundles vary across aninternode but also with the height of a culm.

Fibres: The fibres constitute the scleren-chymatous tissue and occur in the internodesas caps of vascular bundles and in somespecies additionally as isolated strands. Theycontribute to 40 - 50% of the total culmtissue and 60 - 70% by weight. The fibresare long and tapered at their ends. The ratioof length to width varies between 150 : 1 and250 : 1. The length shows considerable varia-tion both between and within species.

Fibre measurements for 78 species weresummarized by Liese and Grosser (1972).Generally, the fibers are much longer thanthose from hardwoods. Different values havebeen reported for one and the same species.The reason is mainly due to the considerablevariation of fibre length within one culm.Across the culm wall the fibre length oftenincreases from the periphery, reaches itsmaximum at about the middle and decreasestowards the inner pan. However, few speciesshow a general decrease from the outer parttowards the center. The fibres in the innerpart of the culm are always much shorter (20- 40%).

An even greater variation of more than100% exists longitudinally within one inter-node: the shortest fibres are always near tothe nodes, the longest in the middle part (Fig.7). With increasing height of the culm there

node

node

fibre lenghtFigure 7. Variation of fibre length within one, internode.

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occurs only a slight reduction in fibre length.As the fibre length serves as an importantcriterion for pulping suitability, any measure-ment has to consider the distinct pattern ofvariation within the culm by taking represen-tative samples.

The fibre length is positively and stronglycorrelated with fiber diameter, cell wall thick-ness and internode diameter, but not withlumen diameter and internode length. Thefibre diameter varies between 11 and 19 urn,the lumen diameter between 2 - 4 um andthe cell wall thickness between 4 -- 6 urn.The ultrastructure of most of the fibres is char-acterized by thick polylamellate secondarywalls. This lamellation consists of alternatingbroad and narrow layers with differing fibrillarorientation (Fig. 8). In the broad lamellae thefibrils are oriented at a small angle to the fibreaxis, whereas the narrow ones show mostly atransverse orientation 1 The narrow lamellaeexhibit a higher lignin content than thebroader ones. A typical tertiary wall is not pre-s e n t , b u t i n s o m e taxa (Oxytenanthera.Bambusa, Ochlandra) warts cover the inner-most layer (Parameswaran and Liese, 1976;1981) The polylamellate wall structure of thefibres especially at the periphery of the culmleads to an extremely high tensile strength, asdemonstrated in engineering constructionswith bamboo culms. Fig. 9 demonstrates

Figure 9. Model of the polylamellate structure of a thickwalled bamboo fibre

the finestructural make-up of a bamboo fibre.The polylamellate structure does not exist inthe cell’walls of fibres or tracheids of normalwood.

In culms with curved internodes noreaction tissue comparable with the tensionwood-fibres of hardwoods has beenobserved, Some of the fibres with secondarywalls possess septa in their lumina as in thecase of hardwoods. The obvious difference isthe presence of secondary thickening of theotherwise normally formed septum with amiddle lamella-like layer and a primary wal1.In the polylamellate fibres it is surprising tofind septa containing several secondary walllamellae, which are continued into the longi-tudinal wall of the fibres. These septa arelignified, a phenomenon normally absent inhardwood fibres.

Phloem: The phloem consists of largethin-walled sieve tubes, among which smallercompanion cells are distributed. The finestructural studies have revealed the presenceof plastids in sieve tubes characterized byosmiophilic cuneate proteinaceous bodiesand lattice-like crystalloids with paralleltubular units. The plastids in sieve elementsare devoid of starch. This type of plastid (PIIb) is characteristic of the Poaceae. ThusBambusaceae belonging to the Poaceae ofthe Order Poales constitute yet another groupwith a definite plastid type, implying itstaxonomic significance, as has been sug-.gested for other families.

The density of the cytoplasm is caused bythe presence of numerous ribosomes. At theperiphery there occurs a rough endoplasmicreticulum, which is extensively developed.Mitochondria with well defined cristae arealso present. Distinct, P-protein-like filamenthave not been observed at any stage. Dictyo-somes are few. Occasionally, microbodies-like structures have been noticed with fila-mentous contents. The peripherally locatednucleus is elongated and lobed. With theaging of the sieve elements there originates avacuole in the centre of the cell, restricting thecytoplasm to the periphery. The plastids stillcontain well-developed cuneate protein-aceous bodies in addition to paracrystallinestructures as well as vesicular and tubularunits. The sieve elements are connected witheach other by sieve pores which are lined withsmall callose platelets.

The wall of the sieve element is charac-terized by microfibrils oriented parallel to eachother in a concentric manner around the celland perpendicular to cell axis, creating astrong birefringence in the polarizing micro-scope. The sieve element wall contains gen-erally only cellin material without obvioussigns of lignification even in mature stages.Due to the prolonged and continuous growthof bamboo culms over more than 30 years it isconceivable that the sieve elements andmetaxylem, vessels remain active in theirtransport function over several decades. Dis-tributed among the sieve elements are com-panion cells, which are characterized bydense cytoplasm and a large nucleus. Mito-chondria are numerous and the endoplasmicreticulum is extensively ramified. Plastids arefew, The companion cells are connected withthe sieve elements by plasmodesmata, whichare branched on the companion cell side witha weak callose development.

Chemical Properties

Chemical constitution: The main con-stituents of the bamboo culms are cellulose,hemicellulose and lignin; minor constituentsconsist of resins, tannins, waxes and inor-ganic salts. The composition varies accordingto species, the conditions of growth, the ageof the bamboo and the part of the culm.Because the bamboo culm tissue matureswithin a year when the soft and fragile sproutbecomes hard and strong, the proportion oflignin and carbohydrates is changed duringthis period. However, after the full maturationof the culm, the chemical composition tendsto remain rather constant. Tables 1, 2 giveapproximate chemical analysis for some bam-boo species. Small differences exist along aculm, as shown in Table 2. The nodes containless water-soluble extractives, pentosans, ash,and lignin but more cellulose than the inter-nodes. The season influences the amount ofwater-soluble materials, which are higher inthe dry season than in the rainy season. Thestarch content reaches its maximum in thedriest months before the rainy season andsprouting. The ash content (1 - 5%) ishigher in the inner part than in the outer one.The silica content varies on an average from0.5 to 4%. increasing from bottom to top.Most silica is deposited in the epidermis, the

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Table 1. Chemical compoadtion of some bamboo0 (Tamolang et al. 1980)

Species

Gigantochlca levis

Gigantochloa aspera

Bambusa vulgaris

Range of valuesfor 10 Indianbamboo species

Range of valuesfor 10 Japanese,Burmese and Indonesianbamboo species

H&cellulose Pentosans Lignin Akoholbenzene(%) (%) (%) (%)

62.9 18.8 24.2 3.2

61.3 19.6 25.5 5.4

66.5 21.1 26.9 4.1

- 15. 1 22.0- 0.2-21.5 32.2 3.2 6.9

61.9- 17.5- 19.8- 0.9-70.4 22.7 26.6 10.8

H o t 1 %water NaOH(%) (%)4.4 28.3

3.8 22.3

5.1 27.9

3.4- 15 .0 -21.8 3.2

5.3- 22.2.11.8 29.8

A s h(%)

5.3

4 .1

2.4

1.7-2.1

0 8-3.8

Silica( % )

2.8

2.4

1.5

0.44

0 l-1.7

Table 2. Chemical coniposition of Phyllostachys pubescens at different heights (Li 1983)

Hot water 1%Holocellulose Pentosans Lignin Ash alcoholbenzene extracts NaOH

(%) (%) (%) (%) (%) (%) ( % )

upper culm 54.1 31.8 24.7 1.2 6.0 7.0 25.6

middle culm 53.6 30.8 24.5 1.2 7.6 8.5 27.6

lower culm 54.4 32.9 24.0 1.1 7.4 9.3 28.3

“skin zone”, whereas the nodes contain littlesilica and the tissues of the internodes almostnone. Silica content affects the pulping pro-perties of bamboo.

Cellulose and hemicellulose: Thecellulose in bamboo amounts - as holocellu-lose - to more than 50% of the chemicalconstituents. As in other plants it consists oflinear chains of 1, 4 bonded hydroglucoseunits (C2H1206). The number of glucose unitsin one molecular chain is referred to as thedegree of polymerization (DP). The DP forbamboo is considerably higher than for dico-tyledoneous woods. Cellulose is difficult toisolate in pure form because it is closely asso-ciated with the hemicelluloses and the lignin.

by hardwoods. With regard to the presence ofarabinose it is closer to softwoods. Thus, thebamboo xylan is intermediate between hard-wood and softwood xylans. These resultsindicate that the bamboo xylan has theunique structure of Gramineae (Higuchi,1980).

Lignin: After cellulose, lignin representsthe second most abundant constituent in thebamboo and much interest has been focusedon its chemical nature and structure. Bamboolignin is a typical grass lignin, which is built upfrom the three phenyl-propane units p-coumaryl, coniferyl, and sinapyl alcoholsinterconnected through biosyntheticpathways.

More than 90% of the bamboo hemicellu- Bamboo grows very rapidly and com-loses consist of a xylan which seems to be a 1, pletes the height growth within a few months4-linked linear polymer forming a 4-0-methyl- reaching the full size. The growing bambooD-glucuronic acid, L-arabinose, and D-xylose shows various lignification stages from thein a molar ratio of 1 .O : 1.3 : 25 respectively. bottom to the top portions of the same culmIt is in the main chain linear, but appears to be (Itoh and Shimaji, 1981). The lignificationdifferent from the xylan found in the woods of within every internode proceeds downwardgymnosperms with regard to the degree of from top to bottom, whereas transversely itbranching and molecular properties. Further- proceeds from inside to outside. During themore, the bamboo xyIan contains 6 - 7% of height growth lignification of epidermaf cellsnative acetyl groups, which is a feature shared and fibres precede that of ground tissue

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parenchyma. Full lignification of bambooculm is completed within one growingseason, showing no further ageing effects. Nodifference has been detected in lignin com-position between vascular bundles and paren-chyma tissue (Higuchi et al., 1966). Bamboohas been chosen as one of the suitable plantsto study the biosynthesis of lignin. lnitially,these investigations were almost exclusivelybased on feeding experiments with radio-active precursors and it has been known thatlignin is synthesized’ from glucose formedby photosynthesis via the “Shikimic acidpathway” (Higuchi, 1969). Several keyenzymes involved in the synthesis of shikimicacid were isolated from bamboo shoots(Fengel and Shao, 1984; 1985).

Physical and MechanicalProperties

Moisture content: The moisture con-tent varies within one culm and is influencedby its age, the season of felling and thespecies, In the green stage greater differencesexist within one culm as well as in relation toage, season and species. Young, one-yearold shoots have a high relative moisture con-tent of about 120 - 130% both at bottomand top. The nodes, however, show lowervalues than the internodes. These differencescan amount to 25% of the water content andare larger at the base than at the top. In culmsof 3 - 4 years the base has a higher moisturecontent than the top, e.g. for Dendrocalamusstrictus about 100% and 60% relativemoisture content respectively. The moisturecontent across the culm wall is higher in theinner part than in the outer part.

The season has a great influence on thewater content of the culm, with a minimum atthe end of the dry period, followed by amaximum in the rainy season, During thisperiod the stem can double its water content.The variation due to the season is higher thanthe differences between base and top as wellas between species. Among species the watercontent varies even in the same locality. Thisis mainly due to the variation in the amount ofparenchyma cells, which corresponds towater holding capacity (Liese and Grover,1961). The considerable differences in themoisture content of freshly felled culms haveto be considered when determining the yieldof bamboo expressed by its fresh weight.

Fibre saturation point and shrink-age: The fibre saturation point is influencedby the composition of the tissue and theamount of hygroscopic extractives. Sincefibres and parenchyma have apparently a dif-ferent fibre saturation point, their varyingamount within a culm leads to differentvalues. The fibre saturation point conse-quently differs within one culm and betweenspecies. For Dendrocalamus strictus the meanvalue was determined to be about 20%, forPhyllostachys pubescens about 13% (Ota,1955) .

Unlike wood, bamboo begins to shrinkright from the beginning of seasoning. Theshrinkage affects both the thickness of theculm walls and the circumference. Seasoningof mature bamboo from green condition toabout 20% moisture content leads to ashrinkage of 4 to 14% in the wall thicknessand 3 to 12% in diameter. Bamboo tissueshrinks mainly in the radial direction, and theminimum deformation occurs in the axialdirection. The tangential shrinkage is higherin the outer parts of the wall than in the innerparts. The shrinkage of the whole wallappears to be governed by the shrinkage ofthe outermost portion, which possesses alsothe highest specific gravity. Mature culmsshrink less than immature ones.

Value of shrinkage from freshly felled tothe oven-dry state were determined for Phyl-lostachys pubescens as follows: tangential:8.2% for the outer part of the wall and 4.1%for the inner; radial: 6, 8% for the outer partand 7.2% for the inner; longitudinal: 0.17%for the outer part and 0.43% for the inner.Shrinkage starts simultaneously with thedecrease of moisture content but does not con-tinue regularly As water content diminishesfrom 70 to 40%, shrinkage stops; below thisrange it can again be initiated. Parenchymatissue shrinks less in bamboo than in timber,while vascular fibres shrink as much as intimbers of the same specific gravity. When themoisture content is low, swelling due toabsorption of water is almost equal to shrink-age. Moist heating leads to irreversible swellingin all directions. The percentage of swellingdecreases with an increase of basic density(Kishen et al., 1958; Sekhar and Rawat,1964).

Seasoning: The cut bamboo should firstb e dried for at least four weeks preferably

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standing upright. Lying horizontally almostdoubles the drying time.

Air seasoning under cover is preferred,but seldom possible. Kiln seasoning undercontrolled conditions can be performed inabout two to three weeks, but is considered tobe uneconomical. The different seasoningbehaviour of bamboo species is chiefly due t othe different culm wall thickness which is themost important factor in controlling the rate ofdrying. The bottom part, therefore, takesmuch longer to season than the top portion.The rate of drying of immature cuims is gen-erally faster than that of mature ones, b u tsince the former have a higher moisture con-tent they need longer. In the initial stagesdrying occurs quite rapidly, but slows downgradually as drying progresses.

Compared with timber of the samespecific gravity, the drying period needed forair or kiln drying is longer due to the higherinitial moisture content and the presence o fwater soluble extractives in the parenchymacells. Their hygroscopicity in humid air is ofabout the same degree as invert sugar. Thewater absorption of dried bamboo therefore isquite rapid compared with that of timber.Bamboos, from which water-soluble extrac-tives have been removed by soaking, d r yfaster and take up moisture slower thanuntreated ones.

Seasoning defects: Several defects canoccur during seasoning. They may be due tothe poor initial condition of the culm, due toexcessive shrinkage during drying or both.

End splitting is not so common or severeas in timber. Surface cracking can occurduring drying with all species. Cracks start atthe nodes but their extent depends on thespecies and wall thickness. Thick-walledmature bamboo is especially liable to crack. Adeformed surface of the round cross-sectionof immature bamboo is common. Thick-walled species evince an uneven outer sur-face, and cracks quite often develop on theinner side of the wall. Considerable shrinkagecan take place in the middle part of the inter-nodes, which become concave.

Collapse is a most serious seasoningdefect. It occurs during artificial as well asnatural drying processes and leads to cavitieson the outer surface and to wide cracks on theinner part of the culm. Green bamboo is aptto collapse due to differential tension during

drying. This shrinkage takes place in the earlystages of seasoning. The outer fiber bundlesare pressed together but the inner ones arestretched and this causes severe stresses.Immature bamboo is more liable to collapsethan mature. Because of faster drying duringthe dry season, collapse occurs more oftenthan during the rainy season. The lowerportion with thicker walls is more liable tocollapse than the upper portion. Slow dryingbamboo species are apparently more liable tocollapse than others.

To avoid seasoning defects, severalmethods of pretreatment have been tried.Soaking in water for two to six weeks did notimprove the seasoning behaviour. Actuallythe devaluation due to checking, splitting andcollapse was more severe in soaked piecesthan in controls. Also water-soaked bamboosmells unpleasant, due to change of i tsorganic constitutents. On the other hand,pieces which have been soaked are not liableto be attacked by powder post beetles duringsubsequent storage as the food material forthe beetles leaches out during soaking.

Presteaming of green bamboo culms didnot improve the seasoning as cracking andcollapse still occur. Heat treatment over anopen fire can be applied if the culms arehalf dry already, i.e. with not more than 50%moisture content.

Changes in colour can occur during sea-soning. Fresh bamboo normally looks greenor rather yellowish according to the stage ofmaturity, it changes during seasoning to alight green shade. Immature bamboos turnemerald green and mature ones pale yellow.Culms which are slowly air-dried develop adarker yellow colour than those which aredried rapidly in a kiln.

Specific gravity and mechanical pro-perties: The specific gravity varies fromabout 0.5 to 0.8 (0.9) g/cm3. The outer partof the culm has a far higher specific gravitythan the inner part. The specific gravity in-creases along the culm from the bottom to thetop. The mechanical properties are correlatedwith specific gravity. Bamboo possesses ex-cellent mechanical properties. These dependmainly on the fiber content and therefore varyconsiderably within the culm and betweenspecies. At the base, for example, the bend-ing strength of the outer part is 2 - 3 timesthat of the inner part. Such differences

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become smaller with increasing height of theculm. With the decreasing thickness of theculm wall there is an increase in specificgravity and mechanical strength of the innerparts which contain less parenchyma andmore fibers, whereas these properties in theouter parts change only slightly. The variationof strength properties is much greater in thehorizontal direction than in the vertical direc-tion (Janssen, 1981),

A close correlation exists between specificgravity and maximum crushing strength. Itseems that resistance to compression parallelto the grain is more or less uniform, hardlybeing affected by the height of the culm. Forbending strength and modulus of elasticity,higher values were obtained from the upperpart. Bamboo splints with the epidermisdownwards have a higher fiber stress, bend-ing strength and modulus of elasticity thanthose with the epidermis upwards. Splintswithout nodes have about one to two timesthe ultimate tensile strength of timbers such asspruce, pine, oak and beech.

The specific gravity of the nodes is gen-erally higher .than that of the internodes dueto less parenchyma, whereas bendingstrength, compression strength and shearstrength are lower. This is due to the irregu-larity of the grain, caused by the arrangementof cells. The presence of nodes thus leads to a

remarkable reduction in all strength proper-ties.

Since there are still no standard methodsof evaluating the strength properties of bam-boo, as in the case of wood, the results arebased on different methods of testing and onwidely varying dimensions (Limaye, 1952;Sekhar and Bhartai, 1960).

The superior tensile strength of bamboo inrelation to wood and steel is demonstrated bythe following comparison: a steel bow of acertain quality (SA 37) of 1 cm2 with 1 mlength has a weight of 0.785 kg and aultimate tensile force of ca. 40 kH; a stickfrom wood with the same length and weightwould have a cross section of 13.5 cm2 and abreaking point at 80 kN, but one from bam-boo with 12 cm2 would resist up to 240 kN;e.g. six times that of steel. The moisture con-tent has a similar infIuence on the strength asit has in timber. Generally in the dry conditionthe strength is higher than in the green condi-tion. This increase in strength with seasoningis more obvious for younger culms than forolder ones. The differences between the airdry and green condition are sometimesrelatively small, especially for bending andcleavage (cf. Table 3) (Ota, 1953).

Table 3. Mechanical properties of Phyllostachys pubescens in the water saturated, air dry andoven dry state (Suzuki 1950)

Property

Bending s t reng thN/mm2

Cleavage s t rengthN/mm2

Shear s t rengthN/mm2

Part

0uter

inner

outer

inner

w h o l e

w h o l e

6

5

watersa tura ted

250

120

7

6

6

9

air dry

270

144

8

8

7

11

oven dry

370

160

8

18

Janka-HardnessN/mm2

outer

inner

e n d 49 63 91

s ide 22 25 37

e n d 27 32 66

s ide 13 17 37

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Influence Of Age

Age is an important factor for the devel-opment of strength properties. It is a generalassumption that bamboos mature until aboutthree years and have then reached their max-imum strength. Investigations with Dendro-calamus strictus have shown that in the greencondition older bamboo culms have higherstrength properties than younger ones (themoisture content of the latter is much higher) In the dry condition, however, higher valueswere obtained at the age of one and two yearsthan from older culms. Tests on splints fromthe central portion of the culm wall indicatedbetter strength properties for one year oldbamboo than for two years old ones, whereasthose of culms of later years were slightlylower. Comprehensive tests by Zhou (1981)revealed a further increase of strength proper-ties with age, viz for radial and tangentialbending strength up to 8 years and for tensilestrength and compression strength (parallel tothe grain) up to 5 years. Older culms (10years) showed a decrease in all strength pro-perties.

Besides the above mentioned variationsof properties within one culm, marked differ-ences exist among individual culms from thesame stand and even more among those fromdifferent localities. Needless to say. strengthproperties vary considerably between differentspecies.

References

FengeI. D. and Shao, X. 1984. A chemicaland ultrastructural study of the bamboospecies Phyl lostachys makinoi Hay.Wood Science and Technology 18: 103-112.

Fengel. D. and Shao, X. 1985. Studies onthe Iignin of the bamboo species Phyl-Iostachys makinoi Hay. Wood Scienceand Technology 19: 131-137.

Grosser. D. and Liese. W. 1971. On theanatomy of Asian bamboo with specialreference to their vascular bundles.Wood Science and TechnoIogy’5: 290-312 .

Grosser, D. and Liese. W. 1973. Presentstatus and problems of bamboo classifica-tion. J. Arnold Arboret. 54: 293-308.

Higuchi, T., Kimura, N. and Kawamura,’ I.1966. Difference in chemical propertiesof lignin of vascular bundles and ofparenchyma cells of bamboo. MokuzaiGakhaishi 12: 173-178.

Higuchi, T. 1969. Bamboo Iignin and its bio-synthesis. Wood Research 48: l-14,(Kyoto)

Higuchi, T. 1980. Chemistry and biochem-istry; bamboo for pulp and paper of bam-boo. Bamboo Research in Asia. Ed. G.Lessard, A. Chouinard. IDRC, 51-56,Ottawa.

Itoh, T. and Shimaji, K. 1981. Lignification ofbamboo culm (Phyllostachys pubescens)during its growth and maturation. Bam-boo Production and Utilization. 104-l 10.In: Proc. XVII IUFRO Congress Group5.3. Ed. T. Higuchi. Kyoto, Japan.

Janssen, J.J.A. 1981. The relationshipbetween the mechanical properties andthe biological and chemical compositionof bamboo. Bamboo Production andUtilization, 27-32. In: Proc. XVII IUFROCongress Group 5.3. Ed. T. HIguchi,Kyoto, Japan.

Jiang Xin and Li Qian. 1982. Preliminarystudy on vascular bundles of bamboonative to Sichuan, Journal of BambooResearch 1: 17-21.

Kishen, J., Ghosh, P.P. and Rehman M.A.1958. Studies in moisture content,shrinkage, swelling and intersection pointof mature Dendrocalamus strictus (malebamboo). Indian Forest Records, NewSer. 1: 11-30.

Li, 1983. Report. Institute of Wood Industry,Chinese Academy of Forestry, Beijing.

Liese, W. and Grover, P.N. 1961. Unter-suchungen uber den Wassergehalt vonindischen Bambushalmen. Ber. DeutscheBotanische Gesellschaft 74: 105- 117.

Liese. W. and Grosser, D. 1972. Unter-suchungen zur Variabilitat der Faserlangebei Bambu s . Holzforschung 26: 202-211.

Liese. W. 1985. Bamboos biology, silvicsproperties, utilization. Gesellschaft furtechnische Zusammenarbeit Schriften-reihe, Eschborn (in press) _

Limaye, B.E. 1952. Strength of bamboo(Dendrocalamus strictus). Indian ForestRecords N.S. 1: 17.

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Ota, M. 1953. Studies on the Properties ofbamboo stem (Part 9). On the reIationbetween compressive strength parallel tograin and moisture content of bamboosplint. Bulletin of the Kyushu UniversityForests 22: 87- 108.

Ota, M. 1955. Studies on the properties ofbamboo stem (Part 11). On the fiber-saturation point obtained from the effectof the moisture content on the swellingand shrinkage of bamboo splint. Bulletinof the Kyushu University Forests 24: 61-72.

Parameswaran, N. and Liese, W. 1976. Onthe fine structure of bamboo fibres. WoodScience and Technology 10: 231-246.

Parameswaran, N. and Liese, W. 1977.Occurrence of warts in bamboo species.Wood Science and Technology 11: 313-318.

Parameswaran, N. and Liese, W. 1980.UltrastructuraI aspects of bamboo cells.Cell. Chem. Technology 14: 587609.

Parameswaran, N. and Liese, W. 1981. Thefine structure of bamboo. Bamboo Pro-duction and Utilization. 178-183. In:Proc. XVII IUFRO Congress Group 5.3.Ed. T. Higuchi. Kyoto, Japan.

Sekhar, A.C. and Bhartari, R.K. 1960,Studies on strength of bamboos: a noteon its mechanical behaviour. IndianForest, 86: 296-301, Dehra Dun.

Sekhar, A.C. and Rawat, M.S. 1964.-Somestudies on the shrinkage of Bambusunutans. Indian Forest 91: 182-188,Dehra Dun.

Suzuki, Y. 1950. Studies on the bamboo(VI). Dependence of the mechanical pro-perties of PhyIIostachys pubescens Magelet H. de Lehaie upon the moisturecontent. Bulletin Tokyo UniversityForests 38: 181-186.

Tamolang, F.N., Lopez, F.R., Semana,J.A., Casin, R.F., and Espiloy, Z.B.1980. Properties and utilization of Philip-pine bamboos. Bamboo Research inAsia, ed. G. Lessard, A. Chouinard.IDRC, 189-200, Ottawa.

Wu, S. and Wang, H. 1976. Studies on thestructure of bamboos grown in Taiwan.Bulletin of the National Taiwan University16: 79.

Zhou, F.C. 1981. Studies on physical andmechanical properties of bamboo woods.Journal of the Nanjing TechnologicalCollege of Forest Products 2: 1-32.

Anatomical Studies on Certain BamboosGrowing in Singapore

A.N. Rao

Depar tment o f Botany, Nat ional Un ivers i ty o f S ingapore,Lower Kent R idge Road, S ingapore 0511

Abstract

Bamboos are common useful plants in theAsian tropics mostly used by the rural peoplefor food, housing and other utility purposes.Like other natural resources their productionis decreasing and there is a renewed interestto promote thei r cul t ivat ion for economicbenefits. The constraints are several includingthe bas ic in fo rmat ion on p lant g rowth , itsstructure and function. It is amazing to see somuch paucity in our knowledge on bambooanatomy. In this paper the anatomical detailsof the shoot apex, axillary buds, young andmature stems, culm and regular leaves androots are presented. The need for fu r therbas ic s tud ies towards improv ing the p lan tgrowth and production is stressed.

Apart from individual scientific contribu-tions, active teamwork is necessary to pro-mote both research and manpower training inAsian countries. The latter is most importantand urgent since there are very few in the fieldwho are familiar with the taxonomy, growthand reproduction of bamboos. Multinationalwork programmes based on the model o fcertain on-going projects are suggested.

Introduction

The history of bamboos is inextricablyinterwoven with the history of man, especiallyin tropical countries. Most of the developingand poor countries are in the tropical zoneand bamboo is a poor man’s plant. The familyGramineae is one of the biggest among angio-sperms with 450 genera and 4,500 species(Willis, 1951). Bamboos are classified into 21genera and 170 species. In tropical Asia alonethere are 14 genera and 120 species (Drans-

field, 1980) Bamboos are the woody grassesthat are comparatively less specialised thanthe herbaceous species in Gramineae. Thetaxonomy of Bambusoideae is based onspikelet structure (Gilliland, 1971) andamong others, the limitations imposed by a)infrequent flowering of the various species,and b) lack of suitable fresh floweringmaterials for study are obvious. Hence,attempts are also made to use vegetativecharacters and here again the details areenumerated by very few observations onfresh materials and the emphasis is based onthe morphology of culm leaves (Gilliland,1971; Holttum, 1958). Although bamboosposses fairly conservative structures manyvariations are seen at subspecific or varietallevels. A detailed study especially in the field aswell as on herbarium materials is necessary.For all practical purposes an illustrated simpleguide to identify the useful bamboos would beof great practical value since biologists ofvarious disciplines are interested in the pro-pagation, genetic improvement and multipleuse of bamboos.

The unique growth habit of bamboos andtheir fast growth rates provide an excellentopportunity to improve the biomass. This isvery important to many of the poorer coun-tries where forest resources are fast depletingand people are faced with many hardshipscaused by the lack of timber and fuel wood(Anon, 1980).

After the earlier work of Arber (1934),nothing much has been,done on the growth,structure, cytology and reproduction of bam-boos. Nevertheless the general interest inbamboos continues among the biologists ingeneral, and the foresters in particular. Theirobservations and reports are published fromtime to time (McClure, 1966). The first Sym-

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posium on Bamboos held in Singapore(sponsored by International DevelopmentResearch Centre of Canada) and the publica-tion of the proceedings therefrom is a signifi-cant contribution in this decade, updating theavailable information on bamboo research inAsia (Lessard and Chouinard, 1980). Mostof the papers published are country or statusreports emphasizing the need to increasebamboo production for economic gains.Some of the authors have clearly emphasizedthe urgent need for further basic research onbamboos that would help the conservation ofgenetic resources and the propagation ofsuperior bamboos in great numbers employ-ing both traditional and modern methods.

Due to a variety of reasons, the bamboosare difficult if not complex materials to workwith and hence the paucity of knowledge onmany basic aspects, including anatomy(Esau, 1965; 1977; Fahn,‘ 1967; Cutter,1971). This paper is a brief report on certainanatomical characters of some wiId and culti-

vated bamboo species present in Singapore.

Materials And Methods

Large mature clumps of bamboo speciesare growing wild in the nature reserves as wellas the cultivated groups in Singapore BotanicGardens. Certain species like Bambusa uerti-cillate and other grass bamboos are also culti-vated in private gardens. About six generaand 23 species are locally present (Table 1).The following eight species are presentlyinvestigated: Bambusa pergracile, B. teres, B.tulda, B. vulgaris, Gigantochloa oerticillata,Schizostachyum brachycladum, S. jaculansand Thyrsostachys siamensis. The materialswere collected, photographed and therequired parts were fixed in FAA. ButyIalcohol series was used for dehydration. Theembedding of tissues, microtoming and stain-ing were carried out following the standardmethods (Sass, 1951).

Table 1. Bamboos growing in Singapore Botanic Gardens with Acquisition Numbers.

1. Bambusa dolichoclada. W. 260B.2 . B. glaucescens. W. 247.3. B. pergracile. W. 253.4. B. teres’ W. 252.5 . B. tulda’ W. 233.6. B. variegata. W. 271.7 . B. ventricosa. W. 232, W. 264A, W. 269, W. 275.8. B. vulgaris’ W. 243A, A. 260A, Y 95, Y 95A.9 . Dendrocalamus pendulus. W. 280.

1 0 . Gigantochloa apus. W. 254, W 277A, W 302.1 1 . G. naname. W. 278.12. G. verticillata’ W. 256B.1 3 . Phyllostachys sp. W. 248, W. 249.1 4 . Schizostachys brachycladum’ W. 231. W. 268, W. 277.1 5 . S. jaculans* W. 154, W. 243.1 6 . Thyrsostachys siamensis’ W. 215, W. 222, W. 237, W. 262, W. 277.1 7 . Bambusa arundinacea.1 8 . B. heterostachya.1 9 . B. ridleyi.20. B. oerticillata.2 1. Dendrocalamus strictus22. Gigan tochloa levis .23. G. ridleyi.

!" Used in the present study; easily accessible and ideally situated for growth studies. 17-23. less commonlyfound due to urbanisation.

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Observations

Morphological considerations: Bothtaxonomic and general descriptions are avail-able for the species mentioned in Table 1, andmany of them are commercially importantspecies (Gilliland, 1971; Holttum, 1958) Hence, these details are not repeated again.The healthy mature clumps of bamboosgrown in Singapore Botanic-Gardens areeasily accessible to study the growth charac-teristics. Due to the humid tropical climate thegrowth, in general, is non-seasonal and newshoots are produced all the year round. Insome species the growth is more profuse inthe post monsoon period of February-April.The fresh bamboo shoots are of varied sizesand shapes, all covered with compactlyarranged culm sheaths (Figs. l-8). The culmsheaths vary in size and shape depending onthe species examined (Figs. ‘A-C). Theelongation of the axis or the culmcommences when the shoots are approx-imately 2-3 feet long, and the cone-shapedstructure becomes axial with distinct nodesand internodes. The culm sheaths are placeddistant apart due to internodal elongation andthey fall off after 120-160 days after the inter-node elongation begins. How long the bam-boo shoots would take, in terms of days orweeks, to emerge out of the soil surface andgrow further into culms is yet to be deter-mined. The bamboo clumps studied presentlyare more than 30-50 years old according tothe records maintained in the Gardens.Although most of the bamboo species grow inclumps there are certain variations amongthem. Some of the clumps are very densedue to heavy accumulation of debris, soil andrhizomes. Size, colour, length of internodesand formation of aerial branches are all vari-able. The basal part of the clump in certainspecies like B. pergracile, B. vulgaris is verywoody, dense and form thick rhizome plexuswhich appears as a raised platform of 2-4 feetabove ground and the dense culms emergeout of the thicket. In other species the begin-ning of each culm can be seen separately.The size, colour and the thickness of thegrowing axes vary among these differentspecies (Figs. A, B, l-4). Some of the axillarybuds at the mature nodes grow to form thelateral branches at the base of which manyroots are formed. The number of youngshoots formed from each bud is variable.

Unlike the culm sheaths, which are variable inshape and size, the lamina of the regularleaves are less distinctive at the species level.They are all dorsiventral structures and theirsizes vary in different species (Figs. l-8). Bothaxillary as well as accessory structures arecommon and the latter are more profuse atthe lower nodes developing into roots. Someof the axillary buds at higher nodes developinto lateral branches.

Shoot apices: The origin and develop-ment of shoots in woody monocots is uniquein many respects. The apices in most of themare conical (Fig. D, l-6). The apex of B.vulgaris is comparatively broader than others(Fig. D, 3). The developing leaf primordia arearranged more or less at the same transverselevel, protecting the shoot apex and contri-buting to the formation of abroad massivestructure (Fig. D, 3). In all of them the devel-oping leaves grow vertically and parallel tothe axis and cover the apex. The photographsin Fig. D, 1-6 are the general view of theapices taken at lower magnification showingapex, developing leaves and their arrange-ment as well as the gradual distinction seen inthe formation of nodes and internodes. Thecloser view of the shoot apices are shown inFig. E, l-8. The tissue organization in themconforms to the generalized angiospermpattern with regular tunica, corpus, peripheraland rib meristems (Fig. E, 1, 3, 5, 7). Thetunica consists of two well defined cell layersand they are distinctly seen in all the speciesinvestigated (Fig. E, 2, 4, 6, 8). The corpuszone is about six to ten layers deep below theinner layer of the tunica with many darklystained, isodiametric cells. The nuclei arelarge compared to cell size and contents. Thetissue below the corpus is highly meristematic.Active growth of this region results in the for-mation of more tissue towards the establish-ment of the stem axis (Fig. E, 2, 4, 6, 8). Thecorpus zone extends into the rib meristembelow and laterally into the peripheral meri-stem, the tissues of which are actively dividingand densely stained (Fig. E, 1, 3, 5, 7). Verymany prominent vascular strands are alsopresent. The rib meristem basal to the corpusdifferentiates into a very distinct intercalarymerisrem with many meristematic cell layers.The derivatives of these layers are added onbasipetally which enlarge and in sections thecentral part of the apex appears lighter incolour (Fig. E, 1, 3, 5, 7).

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The leaf primordia develop at the flank ofthe shoot apex and most of them form theleaf sheaths (Fig. E, 1, 3, 5, 7). Many of themhave a bigger or thicker base and the terminalpart ends as an attenuated structure. Majorityof the primordia have a knick or depression inthe middle and others split in the middle or atthe base (Fig. E, 1, 5, 7). The bamboo shootsare covered by a variety of sheath-like struc-tures that encircle the stem. The variousprimordia develop into culm shea ths ,sheath blades, ligules and other outgrowthson the iigules. Thus the apex as a whole is acentre of immense activity producing a largenumber of primordia that differentiate intomany varied structures subsequently (Fig. E,1,3,5,7).

From about the level of eighth to tenthnode the demarcation between nodal andinternodal regions becomes distinct. Thenodal plates appear as dark cross bars sepa-rating the lightly colaured internodal regions(Figs. D, E). The intercalary meristem at twonodes are enlarged (Fig. G, 8, 9). In the for-mer, the files of actively dividing cells are v e r yclear and neatly arranged. In the latter, whichis an older node the nodal plate has becomethicker with vascular strands traversing in dif-ferent directions. The intercaiary meristem isintact both below and above the nodal plates.The disintegration of cells making way for thehollow cavity is also in progress (Fig. G. 9).

Axillary buds: The bud primordia aredistinct and they can be distinguished fromthe leaf primordia even during early stages ofdevelopment. The latter develop aselongated, slender structures growing acrope-tally over-arching the main apex. in contrastthe primordia of the axillary buds are asym-metrical in outline since the growth is moretowards the leaf than on the stem side. Budsin different stages of development are shownin Fig. F, 1-6. Because of their sloping posi-tion the first prophyli formed towards the axisis shorter, somewhat triangular in outline andgrows parallel to the stem axis and the secondprophyl1 is longer, over-arches the apex andjoins the triangular structure. Both of themcover the developing apex (Fig. F, 5, 6). Themiddle part of the bud enlarges and the sub-sequent leaf primordia originate as lateralstructures. The apical region outgrows the pri-mordia and develops into a broad domeshaped apex. The apex of the axillary budalso shows a two-layered tunica and a regular

corpus region. The leaf primordia remainsmall and more than six to eight prophylis arepresent in certain buds. The first two pro-phylis formed would cover the bud for a longtime and these are well vascularised (Fig. F,6, 7). The subtending axial tissue below thebud undergoes a series of periclinal divisionsand many curved layers of meristematic tissueare present organising the shell zone (Fig. F,6). There is considerable variation in buddevelopment among the different speciesstudied. In B. teres and B. vulgaris, no budinitiation is seen even up to l0- 12 leaf stage.They seem to develop much later (Fig. F, 1,2). In others, such as G. vert ici l lata, S.jaculans, T. siamensis and B. teres the budprimordia develop much earlier (Fig. E, 1, 5,7). More number of apices cut both trans-versely and longitudinally need to beexamined to determine the early or late buddevelopment and their relative positions toone another. This is very important to corre-late the rate of shoot growth and the influenceof bud dominance in branching.

Structure of bamboo shoots: Theconical bamboo shoots were studied in detail(Figs. A, B, l-4). The young axis is sur-rounded by a number of culm sheaths andwhen these are removed one by one theyoung stem is exposed. In B. pergracile, B.vulgaris B. tulda and B. teres the conicalshoots are relatively massive when comparedwith other species (Figs. A, B, l-4). Thecentral cylindrical stem is relatively soft andeasy to section. The various regions of thestem axis were studied a) from the peripheryto the centre and b) from the tip to the base.

The cortical region shows a single layeredepidermis and the surface is usually coveredwith many epidermal hairs (Fig. G, 1, 2, 4).About two to three subepidermal layers alsoconsist of small cell layers followed by theground tissue in which the numerous vascularbundles of different sizes showing varyingstages of development are present (Fig. G, 2-5). In some, only groups of fiber cells are pre-sent with one, two or few vascular elements.Judged by the configuration and structure, itis clear that fiber cells develop early and thereis no synchronisation in development eitherbetween the vascular and non-vascular ele-ments or between the xylem and phloemtissues. Also the peripheral bundles of similarsizes show varied number or quantity ofxylem and phloem tissues. In contrast, the

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Figure F, 1-7. 1. LS. shoot apex B, teres showing development of leaf primordia. 2. L.S. shoot spex Thyrsostachyssiamensis. Note the elongated apex with many leaf primordia and a single axillary bud on r ight hand side of the axis. 3.7. L.S. apex of B. teres showing the development of axillary buds. The early prophylls arch over the apex and centralpart of the bud enlarges. well protected. The central dome and prophylls are well developed as seen in 6 and 7. Two-layered tunica and corpus are very clear in 7.

bundles in the centre are fairly uniform in sizeand contents (Fig. G, 6). Both proto andmetaxylem as well as phloem can be easilydistinguished. The sclerenchymatous capsseem to develop later. In general, it is clearthat the vascular bundle development is cen-trifugal. In B. teres there are many radialvascular strands extending from the periphery

to the cortex (Fig. 6). Since tissues for sec-tioning were taken at random from the differ-ent regions of the cone, no generalization canbe made on the sequential development ofvascular strands with regard to their relation-ship to the main apex or the nodes. It is poss-ible to establish the relative degree of tissuematurity in the massive, conical bamboo

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shoots with reference to the enlargement ofthe axis and the nodal positions. Similarly, acorrelation can also be established betweenthe vascular bundles that are present in theouter and inner cortical regions.

Culm sheath: The bases of culm sheathsare cut along with the tender main axis (Fig. G,4, 5, 7). The transections of these show dis-tinct structural variations between their outerand inner surfaces. As in the stem the outerepidermis consists of a single layer of cells withor without epidermal outgrowths. One or twosubepidermal layers differentiate into scleren-chyma. The rest of the mesophyll is undiffer-entiated and the cells increase in their sizetowards the inner epidermis. The vascularbundles are of different sizes and shapeseither oval or round (Fig. G, 4, 5, 7) coveredall round or partly by prominent sclerenchy-matous bundle caps. In the early stages ofdevelopment, the vascular bundles occupyalmost or more than half of the cross sectionalarea of the sheath. With subsequent develop-ment of the mesophyll, more towards theinner epidermis, the vascular bundles arerestricted more towards the outer epidermis(Fig. G, 5, 7). The inner epidermis is small,one-layered, distinctive with thickwalled cells.Facing the bigger bundles there is a group ofsmaller cells with characteristic thick wallsresembling collenchyma. Many of theenlarged mesophyll cells in T. siamensis hadtwo or more nuclei in them (Fig. G, 7).

Stem structure: The aerial stems of thedifferent species studied show the monocottype of stem anatomy with a distinct epider-ma1 layer, ground tissue and big vascularbundles (Figs. H, 2, 6, 8; I, 1, 3). In S.jaculans the epidermis is more prominentthan in others- with enlarged cells, with threeto four layers of smaller subepidermal cellsthat develop later into regular sclerenchyma(Fig. H, 8). in other species, the subepi-dermal scierenchyma is formed early (Figs.H. 2, 6; I, 3). The ground parenchyma ishomogeneous in nature with cell size increas-ing centrifugally. Additional enlarged cellgroups surrounding the vascular bundles aredistinct in certain species like S. jaculans andB. pergracile (Fig. H, 1, 8, 9) These celllayers may develop into thick sclerenchyma atsubsequent stages. The smaller bundles arearranged nearer the periphery and the largerbundles are towards the centre. The vascularbundles are collateral with sclerenchyma

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sheaths or caps present either in two or threegroups.

In most of the cases, only young stems areused and obviously the distinct fiber strands orcaps are yet to develop. The pith cavity for-mation is distinct in B. vulgaris, S. jaculansand T. siamensis (Figs. H, 6; I, 1, 2). Thestem structure of B. teres is shown in detailwith both the peripheral and central part ofthe axis with intact perenchyma (Fig. H, Z-5).Within the central part there are two distinctvascular bundles, slightly smaller in size thanthose present in the inner peripheral region.The arrangement of the vascular tissues inthese two medullary bundles is similar tothose in the peripheral region. The demarca-tion between the peripheral and centralregions is also clear (Fig. H, 3). Another veryinteresting detail is that most of the enlargedpith cells have two or more nuclei in them(Fig: H, 4, 5). In B. vulgaris the innermost celllayers adjacent to pith are somewhat thick-walled and very distinct almost appearing as aborder zone (Fig. H, 6).

Root structure: As seen in transversesections, the young roots show a number ofepidermal hairs, fairly straight and majority ofthem are uninucleate (Fig. 1, 5). Below theepidermis there are. three to four layers ofsclerenchyma followed by a uniform region ofparenchyma. The stelar structure is typicallymonocotyledonous with regular endodermisand distinct vascular groups of xylem andphloem. Many large air spaces are presentboth in cortex and the stelar regions whichseem to be a common feature in manygrasses. In the older roots the hairs are slightlythicker and many of them have small kinksand curved outlines. In a few cases even thebranching of root hairs is seen (Fig. I, 6, 7).

Root hairs are simple epidermal out-growths, commonly formed on young roots,showing very few or no abnormalities in theircell morphology. Very few cases are knownwhere the root hairs are actually branched(Rao and Chin, 1972). Such details are dis-cussed mostly in relation to certain dicots andthis seems to be the first instance for mono-cots and especially the bamboos (Rao andChin, 1972).

The structure of rhizome and root systemis important since they are adaptable to avariety of soil conditions and prevent soilerosion. In many ways they are much more

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efficient than the grasses which are the earlycolonisers of the cleared or open land.

Leaf structure: Leaves in the familyGramineae are specialised structures. Manyof them are primarily the protective structurescovering the growing parts of t h e rhizome,shoot apices and axillary buds. The rhizomesheaths are simple, triangular in outline withsmall pointed ends and near the apex themargin is sometimes serrated. The structurethat covers the bamboo shoots and youngstems are the culm sheaths which havesmooth, adaxial and rough abaxial surfaces,the latter surface covered with many types ofepidermal outgrowths including hairs (Fig. C,l-3). The culm sheath is also triangular in out-line and the basal part is broad with a narrowterminal part (Fig. C, l-3). Distinct Iigule andauricles may be present at the point where thebroad base slightly narrows down to form thetriangular structure (Fig. G, 9-l 1). The thirdstructure is the foliage leaf with the basalsheath or a petiole and a regular lamina.

The transections of the lamina in differentspecies reveal an upper epidermis, two orthree layers of mesophyll with or without adistinct palisade layer, fairly large air spaces,lower mesophyll and lower epidermis (Fig. J,1-13). The upper epidermal layer is more dis-tinctive than the lower with groups of bulli-form cells which are bigger in certain speciesthan in others (Fig. J, 4. 5, 8. 10. 12). Thegroups of bulliform cells alternate with airspaces. The cuticle is thick on both the layersand in many of them like B. teres, B. tulda,B. vulgaris and G. verticillata the cuticle onlower epidermis is papillate (Fig. J, 3, 5, 8).In S. brachycladum the palisade layer is muchmore prominent. The plicate or lobed condi-tion is common in many of the outermesophyll layers. At places where either airspaces or the bulliform cells are present theupper palisade is restricted to a single layer.The second layer is represented by a group oftwo or four cells that form a bridge intercon-necting the upper mesophyll with the lower.The size and extent of air spaces are also vari-able (Fig. J. 1. 2. 4. 6, 7. 9, 11. 13). In B.tulda, G. verticillata and S. jaculans the pro-minent intercostal ridges are occasionally pre-sent and these form regular hump-like struc-tures and each one of these consists welldeveloped sclerenchymatbus tissue (Fig. J. 9.11). Both the number and the size of bulli-form cells increase between these groups of

sclerenchymatous humps. The vascularbundles in the leaves show the regular mono-cotyledonous structure and a group of scler-enchymatous cells interconnect the vascularbundles with upper and lower epidermis (Fig.J, 3, 10, 12). Stomata are commonly presenton the lower epidermis and in leaf transec-tions the guard cells appear smaller than theepidermal cells and devoid of papillate out-growths or thick cuticle (Fig. J, 3, 5, 12).

Discussion

The well known work on bamboos byMcClure (1966) summarises the basic workdone until 1960s. A critical survey of litera-ture. however reveals the fact that by andlarge the basic botany of bamboos is yetto- be worked out and recorded in a pro-per manner. The literature available at pre-sent is fragmentary, scattered and inadequateand the reasons are not too difficult to under-stand. Like in other aspects of tropical plants.whether wild or cultivated, there is very littleeffort made to study them well by the localscientists. Lack of trained manpower isanother problem. Only taxonomic studies arefairly complete and here again, there is nowell illustrated simple guide, easy to use bythe common man or others not familiar withtechnical terms.

More specifically, as it refers to the presentstudy, it was very revealing to note that thereis hardly any good paper describing theanatomy of bamboos. The list of referencesgiven by McClure (1966) and in the proceed-ings of the last workshop on bamboos in Asiawould substantiate the above statement.Standard recent reference works on plantanatomy (Esau. 1977; Fahn. 1967; Cutter.1971) or even some of the older works(Goebel. 1930; Eames and McDaniels. 1947;Eames. 1961) do not provide much informa-tion due to the lack of any anatomicalresearch. The recent papers published byother Asian or German botanists are noteasily available since they are in local jour-nals. As stated before. bamboo anatomyis hard to work since most of the structuresprovide a good challenge to microtomy andthe structures are relatively difficult to inter-pret. even though many other grassesincluding the various cereal crops are fairlywell studied. Another reason for this inade-

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Figure J, X-13. Leaf transections as seen under low and high magnifications. 1. B pergracile. 2. 3 B teres 4, 5 Btulda 6, 10 S . brachycladum 7. 8, B vulgarIs 9 G, uerticillata. 11 S. jaculans 12, 13. T siamensis the upperand lower epidermis are distinct in all with bulliform cells on the upper and stomata on the lower Sc le renchyma humps areformed in some as seen in 9 and 1 1 Bundles are connected with epidermis by sclerenchyma pegs

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quacy in our knowledge is the generalassumption that all is well with bamboos andthey grow well naturally or in plantation. Onlyrecently when the natural supply is runningshort or inadequate to meet the needs of theincreasing population there is a renewedinterest in increasing bamboo production. Forthe same reason, two international work-shops have been conducted within a period offive years.

Perhaps there are no other single group ofplants that display so many variable vegeta-tive characters as bamboos and our know-ledge about the developmental aspects ofthese is very limited.

The general organisation of shoot apexconforms to the pattern well known in angio-sperms and there is only one earlier study onSinocalamus ( = Bambusa) beecheyana, dis-tributed in China (Hsu, 1944). This work isnot quoted in other works or easily missed forreasons unknown. The axillary bud develop-ment takes place early in the second or thirdleaf axils which is different from the majorityof the species studied presently.

The shoot apex in woody monocotyle-dons is very interesting as recorded in thecase of palms (Ball, 1941; Tan and Rao,1980). The primary thickening meristemcharacteristic of palms (Ball, 1941) is absentin bamboos. The prominent tissues of the flankregion, commonly seen in palms is seen pre-sently only in case of Bambusa vulgaris. Thedifferentiation of many procambial strandsand the prominent peripheral meristem aresimilarities noticed between palm and bam-boo shoot apices. The plicate leaf conditionseen in other monocots is absent in bamboos(Periasamy, 1980).

Some of the bamboo shoots are verymassive structures and they are very richlyvascularised as evidenced by the formation ofvascular strands. A detailed anatomical studyto show the differences between the hardmature culm and the soft tissues in the bam-boo shoots would be interesting and so alsothe node and internode developmentbetween the young bamboo shoots emergingat the ground level and the aerial woodculms. The environmental conditions underwhich these two develop are totally different.

The morphogenesis of different kinds ofaxillary buds, single or multiple, or those that

give rise to leptomorph or pachymorph rhi-zomes will not only be very interesting tounderstand the growth habits of bamboos butalso would help to improve their propagationby vegetative cuttings,

The stem structure is relatively wellstudied and four types of vascular bundles arerecognised which also lend support to the sys-tematics of the group (Liese, 1980; Holttum,1958). The materials studied at present camefrom young stems and the number of scleren-chymatous caps or groups could not beclearly determined for this reason.

The bamboo leaf structure is similar tothose of other grasses with characteristic bulli-form cells, presence of larger air spaces andbig vascular bundles with characteristic bundlesheaths (Esau, 1977). Many of these detailsare also recorded presently. The structuralvariations noticed between regular leaves andculm sheaths are interesting especially the dif-ferences in mesophyll and the nature ofvascular bundles. Whether these differencesare present in all the bamboos is yet to bedetermined and different types of sheathingorgans should be studied in detail. The mor-phogenesis of different types of leaves will beinteresting both from the descriptive andexperimental points of view. It closelyresembles heterophyllous condition since thesame axis from rhizome to fleshy shoots tostrong aerial axes produce three differenttypes of foliar structures. This is an interestingproblem to work with.

As an outcome of the previous workshopmeeting in Singapore several importantresearch needs and priorities were identifiedand recommended. Very briefly these includethe following: a) Studies on culm anatomy todetermine or correlate the strength and struc-tural properties. b) Detailed studies on bam-boo fibres. c) Factors responsible for naturalregeneration in bamboos. d) Identifying theeasily recognisable vegetative characters. e)Propagation by tissue culture and shoot cul-ture for mass production and germplasmexchange. f) To use the juvenile tissues on theculm for large scale propagation. followingthe experiences gained in sugarcane. g) Toidentify very easy methods for vegetative pro-pagation so that the bamboo industry can berevolutionised. h) Increasing the quantity ofpropagules/hectare. i) More frequent use ofbud material for in vitro studies and a few

224

others. The papers presented in the secondworkshop have provided a few or someanswers and indicators to solve some of theproblems posed earlier.

With the number of papers presented inthe form of valuable contributions towardsimproving the quality and quantity of bam-boos in Asia and with different suggestionsmade, we are now in a better position to planfurther activities to achieve the objectives laiddown. Foremost is the need to improve thebasic work on bamboos and here we have touse the existing expertise in different countriesso that no time or money is unnecessarilywasted by repeating the same research in fouror five countries simultaneously, unless thenature of the problem is such that it needsattention by different people in several labora-tories. Several models are already availablelike Asian Mangrove project supported byUNDP and others. Under this project bothtraining and research programmes areincluded with the main objectives of improv-ing the trained manpower for specificresearches. Wherever possible, the skills ofthe staff already working need to beimproved. New staff should be technicallytrained to work on bamboos. Improvement ofbamboos in Asia can be launched as an inter-national project and the different activities canbe coordinated by one or two persons. Anymoney, manpower and efforts spent in thisdirection will pay rich dividends in the nearfuture.

For many of the big world organisationssuch a project may be a very insignificant oneand they may not have the necessary man-power which means establishing a newsection to manage the project. By launching anew medium-sized project for three or fouryears many of such cumbersome procedurescan be avoided which would also bring thedesired results within a shorter period of time.Hopefully the benefits derived can be sharedby all and many of the needs of poor ruralpeople can be easily met.

Acknowledgements

I am grateful to Dr C B Sastry , IDRC,Singapore for inviting me to participate in theworkshop meeting; to my colleagues MrJohnny Wee, Mr Ong Tang Kwee and MdmChan Siew Khim for their technical help and

the National University of Singapore for theaward of research grant FSOF 3/80 underwhich this work has been carried out.

References

Anon, 1980. Firewood crops. NationalAcademy of Sciences, Washington,D.C., USA.

Arber, A. 1934. The Gramineae. CambridgeUniversity Press, Cambridge.

Ball, E. 1941. The development of the shootapex and the thickening meristem. Amer.Jour. Bot. 28: 820-832.

Cutter, E. 1971. Plant Anatomy: Experimentand Interpretation. Addison-Wesley,London.

Dransfield, S. 1980. Bamboo taxonomy inthe Indo-Malesian region. 121-130. In:Proc. Workshop on Bamboo Research inAsia, Singapore. (Eds.) G. Lessard andA. Chouinard. IDRC, Ottawa, Canada.

Eames, A.J. 1961, Morphology of the Angio-sperms. McGraw Hill, New York.

Eames, A.J. and MacDaniels, L.H. 1947. AnIntroduction to Plant Anatomy. McGrawHill, New York.

Esau, K. 1965. Plant Anatomy. John Wiley& Sons, New York.

Esau, K. 1977. Anatomy of Seed Plants.John Wiley & Sons, New York.

Fahn, A. 1967. Plant Anatomy. PergamonPress, Oxford.

Gilliland, H.B. 197 1. Grasses of Malaya.Govt. Printing Press, Singapore.

Goebel, K. 1930. Organographie derPflanzen. Gustav. Fischer, Jena.

Holttum, R.E. 1958. Bamboos of Malaya.Gdns’. Bull. (Sing.) 16: l-35.

Hsu, J. 1944. Structure and growth of theshoot apex of Sinocalamus beecheyanaMcClure. Amer. Jour. Bot. 31: 404-411.

Lessard, G. and Chouinard, A. 1980. Bam-boo Research in Asia. IDRC, Ottawa,Canada.

Liese, W. 1980. Anatomy of bamboo. 161-164. In: Proc. Workshop on BambooResearch in Asia. Singapore. (Eds.) G.Lessard and A. Chouinard. IDRC,Ottawa, Canada.

225

McClure, F.A. 1966. The Bamboos. HarvardUniv. Press, Cambridge, USA.

Periasamy, K. 1980. Development of leafpiication in non-palms and its relation towhat obtains in palms. 108-116. In:Proc. Intl. Symp. Histochemistry, Devel-opmental and Structural Anatomy ofAngiosperms. Madras University, P & BPubl. , Trichy, India.

Rao, A.N. and Chin, S.C. 1972. Branchedand septate root hairs in Melastomamalabathricum. Cytologia 37: 111-118.

Sass, J.E. 1951. Botanical Microtechnique:Iowa State College Press, Ames, Iowa,USA.

Tan, K.S. and Rao, A.N. 1980. Certainaspects of developmental morphologyand anatomy of oil palm. 266-285. In:Proc. Intl. Symp. Histochemistry, Devel-opmental and Structural Anatomy ofAngiosperms. Madras University. P & BPubl., Trichy, India.

Willis, E.J. 1951. Dictionary of FloweringPlants. Cambridge Univ. Press, Cam-bridge.

226

Observations on VascularBundles of Bamboos Native to China

Jiang Xin and Li Qion*

Sichuan Agricultural College, China*Yaan High School, China

Abstract

The arrangement of vascular bundles,presence or absence of cortical air spaces, theextent of parenchyma between the bundlesare used as the important criteria in thepresent study of bamboo types. About 45species of 10 genera are classified under fourmajor types.

Using vascular bundle arrangement as thecriterion in leptomorph rhizomes* of bam-boos, ten genera and 45 species of bamboosnative to China can be classified into the fol-lowing four major types:

Type I Vascular bundles are separated byparenchyma.

(A) No air canals in cortex (Fig. 1). Bam-boos of this type are the following:- Phyllo-stachys arcana, Ph. aurea, Ph. aureosulcata,Ph. bambusoides, Ph. bambusoides var.tanakae, Ph. bambusoides var. castilloni, Ph.bambusoides var. castilloni-inverssa, Ph.besseti, Ph. decora, Ph. dulcis, Ph. flexsuosa,Ph. glauca, Ph. glauca f. yunzu, Ph. meyeri,Ph. nigra, Ph. nigra var. henonis, Ph. nuda,Ph. nuda f. localis, Ph. viridis, Ph. platy-glossa, Ph. praecox, Ph. prapinqua and Ph.pubescens.

Phyllostachys nigra var. henonisFig. 2. Phyllostachys robvstiramea.

l Leptomorph rhizomes are the same as monoaxial and amphiaxial rhizomes. In China the bamboo rhizomes are

divided into three kinds, moaoxial, amphiaxial and sympodial rhizomes

227

Fig. 3. Indocalamus victorialis,

Fig. 4. Pleioblastus amarus.

(B) Air canals are present in cortex (Fig.2). Bamboos of this type are listed as follows:PhyllostAchys robustiramea.

Type II Vascular bundles are isolated.Between them, there are fibres - cell groupsin rectangular, round, or variant forms, andthey are never linked. These are mostly peri-pheral in position. No air canals in cortex(Figs. 3 and 4). Bamboos characteristic of thistype are as follows: Indocalamus longiauritus,1, victorialis, Pleioblastus amarus, P I .gramineus, PI. sp., PI. sp., Psudosasa amabilisand Sinobambusa tootsik.

Type III Vascular bundles are linked,occasionally with very narrow gaps of paren-chyma interrupting Air canals in cortex (Fig.5). This type includes: Phyllostachys hetero-clada and Ph. nidularia. ,

Type IV Vascular bundles are connectedin the form of a ring enclosing stele.

(A) No air canals in cortex (Fig. 6). Bam-boos of this type are as follows: Arundinariafargesii, Chimonobambusa utilis, Ch. qua-drangular&, Ch. purpurea, Qionzbuea lumidi-noda, Sasa unbigena and Sinarundinariafangiana.

I ; I . i n

Fig. 5. Phyllostachys heteroclada.

Fig. 6. Chimonobambusa utilis.

(B) Air canals in cortex (Fig. 7). Bamboosof this type are: Chimonobambusa sze-chuanensis and Qionzhuea opienensis.

Fig. 7. Chimonobambusa szechuanensis.

Observations have shown that there is cor-relation between vascular bundle arrangementmentioned above and with the other vegeta-tive characters of a species. These are usefulcharacters in classification and identification.

229

A Study on the Anatomy of the VascularBundles of Bamboos from China

Wen Taihui and Chou Wenwei

Zhejiang Bamboo Research Centre, China

Abstract

This paper provides anatomical details ofregular vascular bundles of the culms of 28bamboo genera with 100 species and fivevarieties from China, The characteristics ofthe vascular bundles from the outer wall tothe inner wall are also illustrated for certainspecies and this data helps to show thedifference between the consanguinity of thecharacteristics and morphology of thevascular bundles of bamboos of each genus.It also provides valuable reference for iden-tifying bamboo material, articles made of bam-boos, relics and fossils.

The paper also describes a simple methodofpreparing and examining the cross sectionalsurface of bamboos. The method is con-venientfor use infield examination.

The vascular bundles are categorized intofive types, that is, the double broken type,broken type, slender-waist type, semi-opentype and open type.

Variations in vascular bundles and theirusefulness are mentioned.

The anatomical characteristics of the culmvascular bundles are an important supple-ment to the classification of bamboos andappropriale examples are given.

The variations in distribution and anatom-ical characters of Indocalamus and Sasaare discussed. The vascular bundles of Sasa(inclusive of Sasamorpha) are all semi-openwhile those of Indocalamus are mostlyopen type. The arrangement of the vascularbundles of the genera is as follows: Indo-calamus: undifferentiated - semi-differ-ent ia ted - semi-open - open. Sasa(including Sasamorpha): undifferentiated- semi-differentiated - semi-open.

230

Introduction

Anatomy of the vascular bundles of bam-boo culm is a useful guide for bamboo tax-onomy. The details can be used when somebamboos cannot be identified with theirflowers. It is also used in identifying somebamboos from ancient cultural relics. Inaddition, the anatomical details will help todetermine the splitting property, strength andthe ratio of fiber strands of bamboo culm usedby modern papermaking industry, handicraftindustry and other bamboo processing indus-tries. This article introduces a simple methodfor examining culm vascular bundles by usingonly a saw, a knife and a magnifying glass.First cut a culm into three sections, the upper,the middle and the lower part, then smooththe cut with a sharp knife and smear it withwater. This will make the vascular bundlesvisible, if seen through magnifying glass.Bamboos can be identified on the basis ofcharacteristics and features, arrangementsand types of the vascular bundles. If thecross-sectional area of vascular bundlesheaths and the fiber strands are larger, thenthe bamboo wood is strong and contain ahigh percentage of fiber. If the vascularbimdles are evenly distributed the bamboowood has a good splitting property.

Materials and Methods

The plant materials used in this study in-cluded 99 species and 5 varieties belonging to28 genera collected between 1976 and 1983in Zhejiang, Fujian, Guangdong, Yuennan,Jiangxi, Shichuan provinces in China. Eachbamboo culm was cut into three sections, the.upper, middle, and the lower part, about 0.2-0.3 mm thick taken from 5 cm beyond culm

nodes with a sharp knife. After being wetted,the section was observed under a micro-scope, 8 x 15, with a tessellated scale in itseye piece, and the figure was drawn on tessel-Iated paper to the scale. Other techniques likemicrography and tracing were also used.

Serial of the vascular bundles from thesections on the outer wall to the inner wall of3 segments were drawn, so that it could bewell seen from the drawing, size and arrange-ment of the vascular bundles.

Collection of plant materials.

Test No. Scientific Name Place of Col lec t ion

2-1. 1 .2-1 2.2-1. 3.3-1. 4.3-l. 2.3-l. 3.2-2. 4.2-2. 5,2-2. 6.3-1. 5.3-1. 7 .2-3. 7 .3-l. 9 .3-l. 1 0 .3-l. 1 1 .3-l. 1 2 .3-l. 1 3 .3-l. 1 4 .3-1. 15.3-l. 1 6 .3-l. 1 7 .2-3. 8 .3-l. 1 9 .3-1. 20.3-l. 21.3-1. 22.3-1. 23.3-l. 24.3-2. 25.3-2. 26.3-2. 28.3-2. 27.2 - 3 . 9 .3-2. 29.3-2. 322-4. 1 0 .2-4. 1 1 .2-4. 1 2 .3-2. 35.3-2. 33.3-2. 34.2-4. 1 3 .

2-5. 1 4 .

Thyrsostachys s iamensis GambleOxytenanthera nigrocilliata MunroGigan toch loa ligulata GambleDendrocalamus brandissi KurzD. giganteus MunroD. patellanis GambleD. strictus NeesD. latiflorus MunroNeosinocalamus affinis (Munro) Keng f.N. d i s t eg ius (Keng & Keng f.) Keng f. & Wen, ined.N. beecheyanus (munro) Keng f. & Wen, ined.Lingnania chungi i McClureL. wenchouens i s Wen.Bambusa basihirsuta McClureB. breviflora MunroB. dolichomerithalla HayataB. eutudoides McClureB. g ibbodes L inBambusa glaucescens (Wi l l ) S ieb .B. glaucescens var . shimadia (Hayata) Chia ex ButB. nana RoxbB. pervariabilis McClureB. text i l i s McClureB. text i l i s var . albo-stricta McClureB. text i l i s var . glabra McClureB. pachinens is var . hirsutissima (Odash. ) LinB. tuldoides MunroB. vulgris SchradB. subtr imcata Chia ex FungB. lapidea McClureB. oldhami MunroB. pras ina WenDinoch loa utilis McClureD. orenuda McClureCephalostachyum fuchsianum GambleC. pergracile MunroMelocanna humils KurzSchizostachyum pseudolima McClureS. funghomii McClureS. x inwuensis WenS. hainanensis Merr .Ampelocalamus act inotr ichus (Merr . & Chun)Chen. Wen ex ShengChimonocalamus pa/ lens Hseuh ex Yi

231

Yunnan XishuangbannaYunnan XishuangbannaYunnan XishuangbannaYunnan TengchongYunnan XishuangbannaYunnan MangshiYunnan XishuangbannaFujian Fu t ingZhej iang dinghaiYunnan KunmingFujian XiamenZhej iang DinghaiFujian Fu t ingZhejiang DinghaiZhej iang DinghaiZhej iang DinghaiZhej iang DinghaiZhej iang DinghaiZhej iang XunanZhej iang LinhaiZhe j iang Pu j iangZhej iang DinghaiZhej iang Wenl ingZhejiang XiamenZhej iang DinghaiZhej iang DinghaiFujianYunnan KunmingZhej iang DinghaiZhej iang DinghaiZhej iang DinghaiZhej iang FingyangGuangdon HainanGuangdon HainanYunnan MangshiYunnan XishuangbannaFujian XiamenYunnan LuxiYunnan XishuangbannaJiangxi XunwuJiangxi XunwuGuangdon Hainan

Yunnan J inp ing

3-2. 27.4-3. 31.2-5. 15.3-2. 39.3-2. 40.3-2. 41,3-2. 42.3-2. 44.2-5. 16.3-2. 46.3-2. 45.3-2. 47.3-2. 48.5-2. 81.4-2. 23.5-2. 83.5-2. 80.4-1. 17.5-l. 50.5-l. 51.5-l. 63.5-l. 60.5-l. 54.5-1. 52.5-l. 57.5-1. 55.5-l. 56.4-l. 18.5-1. 58.5-l. 624-1. 19.4-2. 20.5-2. 71.4-2. 21.5-2, 70.5-2. 72.5-1. 66.5-l. 67.4-2. 22.5-2. 74.5-2. 75.5-2. 76.5-2. 77.4-2. 25.5-2. 86.5-2. 87.5-2. 88.5-2. 895-2. 90.4-3. 26.5-2. 92.5-2. 93.4-3. 27.

C. f imbr ia tus Hseuh ex YiFerrocalamus strictus Hseuh ex YiFargesia farcta Y iFargesia ampullaris Y iF. chungii (Keng) Wang ex YiF. grossa YiF. se tosa YiF. edulis YiYushania n i i takayamensis (Hayata) Keng f.Y. hirticaulis Wang ex YeY. wixiensis YiY. hasihirsuta (McClure) Wang & YeY. confusa (McClure) Wang & YeChimonobambusa quadragularis MakinoC. setiformis WenC. conoo l ta Dai ex TaoC. armata (Gamble) Hsueh ex YiIndosasa crassiflora McClure1. sinica Chu & Chao1. s h iba taeao ides McClureI . g labra ta Chu ex ChaoS inobambusa in t e rmed ia McClureS i n o b a m b u s a rubroligula McClureS . edu l i s Wen

.

S. glabrecens WenS. nephroaurita Chu ex ChaoS . too t s i k var. Ieata (McClure) WenS . too t s i k MakinoS . anaur i ta WenS . g igan teus WenSemiarundinaria lubrica WenBrachys tachyum densiflorum KengPhy l lo s tachys u i r id i s (Young) McClureP. heterocycla (Carr.) MatsumPhyl los tachys praecox Chu ex ChaoP. stimilosa Zhou et LinP. heteroclada Oliv.P. r u b r o m a r g i n a t a McClurePseudosasa amab i l i s (McClure) Keng g .P. longiligula WenP. contori (Munro) Keng f.P. o r tho t ropa Chen ex WenP. no ta ta Wang ex YeP l e i o b l a s t u s a m a r u s (Keng) Keng f.PI. ch ino MakinoPI. ovatoauritus Wen, inedPI . h i s iaenchuens i s WenPI. kwangsiensis HsiungPI . matsuno i (Makino) NakaiPI. gramineus (Bean) NakaiPI. o l eosus WenPI. maculatus (McClure) Chu ex ChaoClau inodum bedogona tum (Wang et Ye) Wen

Yunnan LuxiYunnan J inp ingYunnan LuxiYunnan LuxiYunnan Mongsh iYunnan L i j i angYunnan ZhongdianYunnan KunmingZhej iang LinanJiangxiYunnanFujian C h o n g a nJiangxi HuanganFujian SanminFujian WuyishanYunnan LuxiGuangxi LuyeGuangxi NanningYunnan HekouGuangxi Gui l inFujian WuyiSichunan ChangningGuangzhouYunnan MalipoZhej iang QinguanGuangxi quangzhouFujian anxiFujian anxiJiangxi J ingangshanZhej iang LongquenZhej iang LongquenZhej iang J inghuaZhejiang Lin haiHangzhouZhej iang LinhaiZhej iang LinhaiZhej iang LinhaiZhe j iang LuoqingJiangxiGuangxi QuanzhouGuangzhouZhej iang TaishunFujianFujian J ianyangFujian XiamenZhej iang LuoqingZhej iang QingyuanZhe j i ang Yong j i aFujian ShanghangGuangzhouJiangxi FongxingFujian J iang ouJ iangxi Wuyishan

232

Test No. Scientific Name Place of Col lec t ion

4-2 . 24 . Ol igos tachyum sulcatum Wang ex Ye4-3. 28. Indocalamus tessellatus (Munro) Keng f.

Fujiang MingqingZhejiang qingtin

5-2 . 98 . I. Iongiauritus Handel-Mazz5-2 . 97 . I. Iatifolius McClure5-2 . 96 . I. mo g o i (Nakai) Keng f.4-3 . 29 . Gel idocalamus stellatus Wen5-1 . 64 . Sasa q ingyuanens i s Hu4-3 . 30 . S. sinica Keng

Variations in the VascularBundles

The vascular bundle includes both theconducting tissue and the mechanical tissue.Joining up the plant parts, the undergroundrhizomes and the upper leaves, as a whole,the vascular bundles transport nutrientsolution by vessels and sieve tubes. Becauseof the large size of the bamboo plant the con-ducting tissue is reinforced by an outsidemechanical tissue which may facilitate circula-tion.

Some species even have one or two fiberstrands. The sectional area of these fiberstrands is usually greater than that of thecentral vascular bundle. The parenchyma inthe vascular bundles serves as a buffer zonecontributing to the elasticity of the culms,without which the culms would be inflexibleand brittle. Near the epidermis, there are gen-erally one or two layers of fiber bundles,closely arranged giving mechanical strength.These are followed by one to three layers ofsemi-differentiated vascular bundles withincipient conducting tissue. Further inside areregular vascular bundles, generally in thecentral part of the culm section, two to ten innumber.-The shape and arrangement of thevascular bundles near the inner wall are irre-gular, and the position of sclerenchymabundle sheath varies from sideward to out-ward or inward.

Although the morphology of the vascularbundle varies a lot, it remains relatively stablewithin a given internode of a species.

The Evolution of the VascularBundle in Sympodial Bamboos

Sympodial bamboos are said to be com-

Jiangxi DaiyuJiangxi XunwuFujian WuyishanJiangxi DaiyuZhej iang QingyuanZhej iang Linan

paratively primitive with wide range of dif-ferentiation. Based on vegetative charactersthe sympodials are divided into two groups,sympodial rhizomes with short necks (clump)and long necks (spreading). The formerinclude genera Thyrsostachys, Dendro-calamus, Lingnania, Bambusa, Ampelo-calamus and Schizostachyum, and the latterChimonocalamus, Fargesia, Yushania.Melocanna, Pseudostachyum etc. Theinflorescences are indeterminate as inBambusa, Dendrocalamus, Lingnania,Thyrsostachys and determinate in Ampelo-calamus, Chimonocalamus, Fargesia,Yushania etc. The anatomical details of thevascular bundles reflect the main evolutionarytrends.

The sympodial genera that possess thedouble-broken and broken types of vascularbundle are Thyrsostachys, Dendrocalamus,Lingnania, Bambusa, Schizostachyum,Gigantochloa, Oxytenanthera, Neosino-calamus etc.

Schizostachyum, Cephalostachyum,Melocanna are sympodial but taxonomistsusually do not treat them as the same, butgroup them separatly as a tr ibe namedMelocanneae or Schizostachyeae. This clas-sification of a sub-tribe can be justified since allthese genera have the bundles which are notthe broken type but slender waist type. Thesympodials with long necks like Fargesia andYushania are distributed at high elevationwith advanced indeterminate inflorescensewhich is considered more advanced than thesympodial with short neck type, also they havetheir representive vascular bundles as openor semi-open type and not slender waist type.

233

The Character of VascularBundles of Running TypeBamboos

The monopodial and amphipodial type ofbamboos have long been classified into twomajor categories. The anatomical details ofthe vascular bundles are not distinct in thesetwo categories. They both have open andsemi-open type of vascular bundles, (exceptin few species o f Chimonobambusa).Although Phyllostachys is a monopodialgenus, sometimes we can also find speciesthat have amphipodial rhizomes, such as P.heteroclada, P. bombusoides and P. makinoi.The anatomy of the vascular bundles ofrunning type of bamboos is different fromthat of clump type. Besides, the form andstructure of the vascular bundles are differentfrom one another.

1) The typical semi-open type of vascularbundles are found in Sass, Gelidocalamus,Semiarundinariu, Clavinodum, Oligo-stuchyum, and the Subgen. Pleioblastus,Pleioblustus gramineus, P. matsunoi etc. Ofthese, Sass and Semiarundinaria consist ofvascular bundles which are somewhat typical.In Sasa the upper, middle, or the lower parthave about six bundles but in Semiarun-dinaria there are four vascular bundles in theupper part, five in the middle and eight in thelower part. The typical vascular bundles ofGelidocalamus are of semi-open type exceptthose near the inner wall of the upper part ofthe culm which are of open type. The vascularbundles of Subgen. Pleioblastus are all ofsemi-open type.

2) The genera that have all or nearly allopen -type vascular bundles areFerrocalamus, lndocalamus and Pseudosasa.Ferrocalamus has clump type, but its rhi-zomes are amphipodial and the vascularbundle of the culms are of open type. The un-differentiated vascular bundles on the outerwall of the culms of Ferrocalamus are excep-tionally big; therefore, the tissue in the wall iswell developed and forms a strong and hardouter wall. Almost all the vascular bundles ofPseudosasa and Chimonobambusa are ofopen type. The regular vascular bundles ofother genera are mainly open type.. In theprocess of changing from undifferentiatedvascular bundles to regular ones, the semi-’open type gradually changes into open type.

In this changing process Indocalamus usuallyshows semi-open type before the regular opentype appears.

3) Open and semi-open type vascularbundles exist at the same time and sometimesthey are of equal number, for example, Phyl-lostachys, Brachystachyum and species ofSubgen. Pleioblastus, as Pleioblastus amarus,Pleioblustus hsienchuensis, Pleioblastueoleosus and Pleioblustus maculatus. Phyllo-stachys is intermediate among the runningtype, that is to say, the typical open typevascular bundles of Phyllostachys are nearlyas many as the semi-open ones. The regularvascular bundles of Brachystachyum aremainly of open type, while those of Subgen.Pleioblastus are mainly semi-open type.

4) Regular vascular bundles are mainly ofopen type, but sometimes near the inner walland outer wall of the culms semi-open typevascular bundles are found, and among thegroups of vascular bundles there are layersof parenchyma. These can also be foundin both Indosasa and Sinobambusa, whichshow that the two genera not only look alikein their appearances but also have similarvascular bundle features.

A Generic Key to the VascularBundles of Bamboos

1. The culm vascular bundles is brokenonce or twice in the middle and the lower orupper parts of the central vascular bundle hasa proliferation of fibre strands,

2. Co-existance of the broken type anddouble broken type of vascular bundles.

3. The lower part of the culm with thedouble broken type vascular bundles, themiddle and upper parts with the broken typevascular bundles.

4. The vascular bundles of the lower partof the culm are mostly double broken type.

5. The lower part of the culm with a con-siderable number of vascular bundles, theupper and middle parts with a sudden reduc-tion of vascular bundles, the lower part withvascular bundles over twice as many as thosein the. upper and middle parts . Thyrsostachys

5. The lower part of the culm with manyvascular bundles, but gradually reducing from

234

the middle part upwards . . . . . . Gigantochloa

4. The lower part of the culm with fewdouble broken type vascular bundles.

5, The lower part with outer vascularbundle sheath developed particularly well andits section area is larger than the sum total ofother vascular bundle sheaths , . . . . . . . . . . . .. . . * . . . . . . . . . . . . . . . . . . . . Dendrocalamus

5. The lower part of the culm with outerbundle sheath particularly well-developed andits section area is as large as that of the left andright side vascular bundle sheath or smaller . .. . . . . . . . . . . . . . . . . . . . .Oxytenanthera

3. The lower and middle parts or only themiddle part of the culm with the double brokentype vascular bundles.

2. The culm with the broken type andwithout the double broken type vascularbundles.

3. In the middle of the cross section sur-face of the upper, middle and lower parts ofthe culm or near the inner wall, scalariformvessels are specially big . . . . . . . . . . Lingnania

3. Scalariform vessels of the vascularbundles of the culm are of the common size.

4, One open type vascular bundle nearthe inner wall . . . . , . . , , . . . Neosinocalamus

4. Two open type vascular bundles nearthe inner wall are changeable (a few specieswith the double broken type vascular bundles).. . . . . . . . . ..*.......*.....*.... Bambusa

1. Vascular bundles of the culm do notbreak, fibre strands do not proliferate at theupper and lower parts of the central vascularbundle.

2. With the slender-waist type vascularbundles.

3. The lower part of the culm with a row ofover ten vascular bundles, the upper andmiddle parts with a sharp reduction . . . . . . . . .. . . . ..*....*...*....*. Cephalostachyum

3. The lower part of the culm with rela-tively fewer vascular bundles, the vascularbundles in the upper, middle and lower partsare almost equal in number.

4. Culms slender but with fairly bigvascular bundles, the inner sheaths of vascularbundles near the inner wall are normal , . . . . .. . . . - . . . . . . . . . . . . . . . ‘ . . . . . . . Melocanna

I4. Culms thick but with. comparatively

small vascular bundles, the inner sheaths ofvascular bundles near the inner wall are un-developed . . . . . . . . . . . . . . . Schizostachyum

2. With the open type and semi-opentype vascular bundles.

3. With the open type regular vascularbundles.

4. The undifferentiated and semi-differ-entiated vascular bundles are especially well-developed, the sectional area of sclerenchymais one to three times the size of the regularvascular bundles . , . . . . . . . . . . Ferrocalamus

4. The undifferentiated and semi-differ-entiated vascular bundles are a little biggerthan regular vascular bundles.

5. The outer vascular bundle sheath of thesemi-differentiated vascular bundle is espe-cially well-developed. and is one to threetimes as big as other vascular bundle sheaths. . . . . . . . . . . . . . . . . . . . . . . .Pseudosasa

5. The outer vascular bundle sheath of thesemi-differentiated vascular bundle is almostas big as or a little bigger than other vascularbundle sheaths . . . . . . . . . Chimonobambusa

3. All the vascular bundles are semi-open.

4. The semi-differentiated vascu tarbundles are two times bigger than regularbundles . . . . . . . . . . . . . . , , . . Gelidocalamus

4. The semi-differentiated vascularbundles and regular vascular bundles arealmost equal in number.

5. A row of about three to four vascularbundles, amphipodial rhizomes . , , . Subgen.

Pleioblastus

5. A row of more than five vascularbundles.

6. The lower part of the culm with a row offive to six vascular bundles.

7. Semi-differentiated vascular bundles,and the inner vascular bundle sheath is almostrectangular.. . . . . . . . . . , . . . . . . . . Yushania

7. Semi-differentiated vascular bundles,and the inner vascular bundle sheath istriangular . . . . . . . . . . . . . . . . . . . . . . . . . Sasa

6. The lower part of the culm with a row ofseven to eight vascular bundles, the innersheath of the semi-differentiated vascularbundle is triangular, the outer sheath is oval . .. . . . . . . . . . . . . . . . . . . . . . . . . Semiarudinaria

235

3. The open type and the semi-open typevascular bundles coexist.

4. Mainly with the semi-open typevascular bundles.

5. The vascular bundles in the lower partof the culm are all semi-open, near the innerwall of the upper and middle parts are two orthree open type vascular bundles . . . Fargesiu

5. Near the inner wall of the upper,middle or lower part are one to two open typevascular bundles.

6 . The inner vascular bundle sheath of thesemi-open type vascular bundle in the threeparts of the culm is triangular. . . . , . . Subgen.

Amarus

6. The characteristics and morphology ofthe inner vascular bundle sheath of the semi-open type vascular bundles are irregular . . . . .. . . . . * . . . . . . . . . . . . . . . . . . . . * Clavinodum

4. Mainlybundles.

with the open type vascular

5. The semi-differentiated vascularbundles and the regular vascular bundles arealmost equal in size . . . . . , . . . . Phyllostachys

5. The semi-differentiated vascularbundles are bigger .than regular vascularbundles.

6. The outer sheath of the semi-differen-tiated vascular bundle is almost as big as theouter sheath of the regular vascular bundle . .. . . . . . . . . . . . . . . . . ..‘....... Zndocalamus

6. The outer sheath of the semi-differen-tiated vascular bundle is quite well-developed,and far bigger than the outer sheath of theregular vascular bundle . . . Brachystachyum

4. The open type and the semi-open typevascular bundles coexist; sometimes there areparenchyma cell rings among groups ofvascular bundles or the open type vascularbundles among the semi-open type vascularbundles.

5. The vascular bundles in the uppermiddle and lower parts of the culm are in aratio of 4:5:9. shaped like an upside-downpagoda . . . . . . . . . . . . . . . . . . . . . . . lndosasa

5. The vascular bundles in the upper,middle and lower parts of the culm are in aratio of 6:8:8. almost equal in number . . . . _ .. . . . * . . . . . . . . . . . . . . . . . . . . . Sinobambusa

500um 5OOum lOOum lOOum

Fig. 1. Morphology of vascular bundles of bamboo. 1. Dendrocalamus strictus Nees. 11. Bambusa peruariabilis

McClure. III. Melocanna humilis Kurt. IV. Phyllostachys oiridis (Young) McClure. V. Fargesia farcta Yi.1. non-differentiated vascular bundles; 2. semi-differentiated vascular bundles; 3. double-broken vascularbundles; 4. broken vascular bundles; 5. slender waist vascular bundles: 6. open vascular bundles; 7. semi-openvascu la r bund les .

236

Fii. 2-1. sections of the upper, middle and lower of bamboo culm from left to right is outside to inner wall.1. Thyrsostachys siamensis Gamble; 2. Oxytenanthera nigrocilliata Munro; 3. Gigantochloa ligudata Gamble.A. lower of culm; B. middle of culm; C. upper of culm.

Fii. 2-2. 4. Dendrocalamus atrictus Nees; 5. Dendrocalamus latiflotus Munro; 6. Neosinocalamus affinis (Mumro)Keng f .

237

!"-

Fig. 2-5. 14. Chimonocalamus pal/ens Hseuh et Yi; 15. Fargesia farcta Yi; 16. Yushania niitakayamensis

(Hayata) Keng f.

239

1 2 3 4 5 6 7 8 9

16 17 18 19 20 2 1 22 23 24

Fig. 3-1. The morphology of vascular bundles of bamboos. ali the test No. l-24, see the table.A. lower of culm; B middle of culm: C. upper of culm

25 26 27 28 29 30

Fig 3-2 The morphology of vascular bundle of bamboos. all the test No 25-48, see the table,A lower of culm. B middle of culm. C lower of culm

240

Fig. 4-l. Sections of the upper, middle and lower of bamboo culm, from left to right is outside to inner wall.A. lower of culm; B. middle of eulm; C. upper of culm. 17. Indosasa crassifllora McClure; 18. Sinobambusatootsik Makino; 19. Semiarundinaria lubrica Wen.

Fig. 4-2. 20. Brachystachyum densijjorum Keng; 21. Phyllostachys heterocycla (Carr.) Matsum; 22. Pseudosasaamabilis (McClure) Keng f.; 23. Chimonobambusa marmorea Makino; 24. OIigostochyum sulcatum C.P. Wang etYe; 25. Pleioblastus amarus (Keng) Keng f.

241

5OOum

Fig. 4-3. 26. Pleioblastus gramineus (Bean) Nakai; 27 Clauinodum oedogonotum (C.P. Wang et Ye) Wen;

28. Indocalamus tessellatus (Munro) Keng f.; 29. Gelidocalomus stellatus Wen; 30. Sasa sinica Keng;31. Ferrocalamus strictus Hsueh et Kens. f.

58 59 6 0

A

Fig. 5-l. The morphology of vascular bundle of bamboos, all the test No. 50-67. see the tablesA lower of culm; B.. middle‘of culm; C. upper of culm

242

6 8 6 9 70 71 72 73 74 75 76 77

87 88 89 90 91 92 93 94 95 96 97 98 99

Fig. 5-2. The morphology of vascular bundle of bamboos. all the test No. 68-99. see the tables.A. lower of culm; B. middle of culm; C. upper of culm. (The construction of the key is left in itsoriginal form but this can be further simplified References, other detaib and explanations connectedwith this paper can be obtained from the authors - Eds).

243

Anatomical Properties of Some BamboosUtilized. in Indonesia

Elizabeth A. Widjaja and Zuhaida Risyad

National Biological Institute, Bogor and Faculty of Forestry,Bogor Agricultural University, Bogot, Indonesia

AbstractFour species of bamboo (i.e. Dendro-

calamus giganteus, Dendrocalamusasper Gigantochloa robusta, Bambusavulgaris, oat. striata) utilised in Indonesiaare studied anatomically and the results arecorrelated to their mechanical properties.There is a correlation between fiber length,modulus OS elasticity and compressionstrength.

IntroductionAmong the sixteen species of bamboo uti-

lized in Indonesia (Widjaja, 1980), ten ofthem (i.e. Gigantochloa apus (Schult. &Schult.) Kurz, . Gigantochloa verticillata(Munro*), Gigantochloa robusta Kurz, Gigan-tochloa atter (Hassk.) Kurz, Dendrocalamusasper (Schult.) Backer ex Heyne, Bambusaarundinacea (Retz.) Willd., Bambusa vulgarisSchrad. var. striata, Bambusa blumeanaSchult., Gigantochloa aff. atter* and Bam-busa polymorpha Munro) are useful in thebuilding construction, ( !" hereafter referred toas Gigantochloa pseudoarundinacea (Steud.)W i d j a j a a n d Gigantochloa atroviolaceaWidjaja respectively). Their mechanical pro-perties, however, have yet to be determined.Grosser & Liese (1974) concluded that thepercentage of sclerenchyma fibres increasesfrom the bottom to the top of the culm, accom-panied by compression strength. Janssen(1981) pointed out that the bending stressdecreases with the height of the culm but themodulus of elasticity increases with the latter.Kawase (1981) reported that the fiber size inthe middle part of culm is greater than in thebottom and the top, and that the outerpart of the culm has longer fibers than theinner part.

In this paper, the correlation between thefibre length and the mechanical properties(including compression strength, tensilestrength, static bending strength and stiffness)of Dendrocakamus asper, Gigantochloarobusta, Bambusa vulgaris var. striata andDendrocalamus giganteus, is studied.Although D. giganteus is not cultivatedoutside the botanical gardens in Indonesia, itis included in this study because of its poten-tial value for building purposes.

Materials and Methods

This study was based on 4 species ofbamboos grown in the Bogor BotanicalGardens.

Samples were obtained by taking thenodes at the height of 1.5 m above theground. By counting that node as the firstone, further samples were also taken from thethird, fifth and seventh nodes further up ofthe culms. For studying the fibre length,pieces of culm were macerated in 50% HNO3

at 5OoC for 15 minutes. After washing in dis-tilled water it was stained with 1% methyl-green in 10% acetic acid and mounted in 50%glycerin. The mechanical properties of theculm was determined by Baldwin instrument(to measure the tensile strength) and Amsler6000 kg (to measure the static bendingstrength and the compression strength). Thesamples used for this study measured 30 cmx 2 cm x 0.5 - 1 cm, following theAmerican Standard for Testing and MaterialsASTM D 143 52 (1972) with some modifi-cation.

Results and DiscussionAnatomical properties: The fibre length

showed that Dencrocalamus asper has thelongest fiber (averaging 20.03 mu), followed

244

by Bambusa vulgaris var. striata (18.92 mu,Dendrocalamus giganteus (18.84 mu), andGigantochloa robusta (18.12 mu). Based onthe position along the culm, the first nodestudied generally has similar fiber sizes (19-20mu). The fiber length in the third node andabove do not show a genera1 pattern (Table1).

Mechanical properties: Sjafii (1984)showed that Dendrocalamus giganteus hasthe highest specific gravity (0.7 1) if comparedto Dendrocalamus asper (0.61) Giganto-chloo robusta (0.55), and Bambusa vulgarisvar. striata (0.52). However, there is no signi-ficant difference between various nodes ofevery species. With regard to the average rateof the modulus of elasticity, modulus ofrupture and compression strength, Dendro-calamus giganteus also has the highest value,followed by Dendrocalamus asper, Gigan-tochloa robusta and Bamb’usa vulgaris var.striafo (Table 2). The tensile strength ofDendrocalamus giganteus (1907.33 kg/cm2)is smaller than Dendrocalamus asper

Table 1. Fiber length at variousnodes of culm

Species Node Fiber Length Average

D. giganteus 1st 19.163rd 18.045th 19.16 18.847th 19.0

D. asper 1st 19.283rd 19.605th 21.16 20.037th 20.10

G. robusta 1st 19.663rd 1 55th 19.66 18.127th 18.16

B. vulgarisvar striata

1st 19.923rd 20.245th 18.2 18.927th 17.2

Table 2. Mechanical properties of various bamboos at various nodes (after Sjafii. 1984)

Species Par t Modulus of Modulus of Compression T e n s i l eof elasticity rupture s t reng th strength

culm kg/cm2 kg/cm2 kg/cm2 kg/cm2

D. giganteus 1

7Average

172097.92 1828.57 602.56 1836.16122463.95 1758.28 619.88 1945.91147912.10 1827.90 639.95 1880.20130352.42 2880.13 645.84 1965.87143206.60 1823.72 627.02 1907.04

D. asper 1 122073.82 1637.81 639.30 2145.033 149587.06 1741.61 592.35 2040.155 129542.12 1595.74 622.20 2219.897 123966.17 1578.62 565.93 2103.97

Average 131292.29 1638.45 604.95 2127.26

G. robusta 1 94208.59 1384.48 533.12 1970.513 92367.13 1294.27 509.97 1766.825 109217.50 1398.23 510.95 1853.657 97381.90 1345.62 529.62 2066.33

Average 98293.78 1355.65 520.92 1914.33

B. vulgaris

var. striota

1

7Average

60652 -42 1075.01 484.30 1391.9471931.76 1123.66 443.02 1196.1588297.55 1105.27 475.34 1351.6683939.92 1286.24 417.43 1346.4676205.41 1147.54 455.02 1321.55

2 4 5

35

Table 3. Correlation between Fiber length and E-Modulus, R-Modulus,Compression Strength and Tensile Strength

Linear Regression CorrelationCoef icient

F

Fiber length 0.3 8.48’ !E-Modulus: 30.568,72 + 4162.96

R-Modulus: 1485.08 + 0.33 Fiber length 0.0001 0.00096

Compression strengh: -42.69. + 31.33 Fiber length 0.03 11.09’ !

Tensile strength: 1599,76 + 13.45 Fiber length 0.1 0.99

(2127.26 kg/cm and Gigantochloa robusta(1914.33 kg/cm2), with Bambusa vulgarisvar. striata has the lowest tensile strength(1321.55 kg/cm2), The. result of the test ofmodulus of elasticity of Bambusa vulgaris var.striata. supports the f indings of Limaye(1952), Janssen (1981) and Kawase (1981)who showed that the elasticity of the Iowerculm is smaller than the upper one. Themodulus of rupture of the 4 species studiedalso bears out the conclusion of Limaye(1952) who pointed out that the decreasing ofmoduilus of rupture follows the decreasing ofspecific gravity. The compression strength ofDendrocalamus giganteus and Gigantochloarobusta increases from the bottom to the topbut not so in Dendrocalamus asper andBambusa vulgaris var. striata. As pointed outby Limaye (1952) and Janssen (1981) thecompression strength as well as the percentageof sclerenchyma fibre increase from thebottom to the top. According to Sjafii (1984),the modulus of elasticity can be used fordetecting the modulus of rupture due tothe highest correlation. Also, the compressionstrength and the tensile strength can bedetected by the modulus of elasticity althoughthe correlation is very small. Further anaIysesof the data obtained on the four e speciesstudied indicate that the fiber length have acorrelation with the modulus of elasticity andcompression strength (Table 3) although it isvery small- in the latter (r = 0.03). Furtherstudies along these lines are now in progresson other species of utilized bamboos inIndonesia and it is hoped that the result will bebeneficial in utilizing the anatomical propertiesfor practical purposes.

References

Grosser, D. & Liese, W. 1974. Verteiiung derLeibundel und zeliarten in sprossachsenverschiedenen Bambusarten. HoIz alsRol -und werkstoff. 32: 473-482.

J a n s s e n , J . J . A . 1 9 8 1 . T h e reIationshipbetween the mechanical properties andthe biological and chemical compositionof bamboo. In: Higuchi, T. (ed.).Bamboo production and utilization. Pro-ceedings of the Congress Group 5.3A,Production and Utilization of bambooand related species, XVII, IUFRO WorldCongress Kyoto, Japan.

Kawase, K. 1981. Distribution and utilityvalue of Sasa bamboo. In: Higuchi, T.(ed.) . Bamboo production and utiliza-tion. Proceedings of the Congress Group5.3A, Production and Utilization ofbamboo and related species, XVII,IUFRO World Congress Kyoto, Japan.

Limaye, V.D. 1952. Strength of bamboo(Dendrocalamus strictus). Indian Forester78: 558-575.

Sjafii, L.I. 1984. Pengujian sifat-sifat fisi danm e k a n i s c o n t o h kecil b e b a s cacatbeberapa jenis bambu. Thesis FakultasKehutanan, Institute Pertanian Bogor,Bogor.

Widjaja, E.A. 1980. Indonesia (countryreport). In: Lessard, G. & Chouinard, A.(ed .) . Bamboo research in Asia.Proceedings of a workshop held in Singa-pore. Pg. 201-204.

246

Fibre Morphology and Crystallinity ofPhyllostachys pubescens with Reference

to AgeSun Chengzhi and Xie Guoen

Research lnstitufe of Chemical Processing and Utilizationof Forest Products, Chinese Academy of Forestry

Beijing, China.

Abstract

The fibre form and crystallinity of Phyl-lostachyus pubescens we determined inrelation to the age of the culm. This studyhelps to determine the age of the bambooharvest.

Introduction

For purpose of investigating the fiber formand the relative crystallinity of cellulose ofPhyllostachyus pubescens Maze1 ex H. deLehaie, culms of different ages were used. Thebamboo grows rapidly, and the differentsamples taken indicate the change of fiberform at each stage of growth in relation to itsage.

Materials and MethodThe materials were obtained from the

stands of P, pubescens (from 1/2 1, 3, 7years old) growing in Zhejiang province.From each bamboo culm, three portions fromthe base, the middle and the top were cut off.After air-drying, specimens of 2-3 cmin length were prepared from the centralpart of each joint. From the thick partsof the bamboo culm, specimens weretaken, and named T1, T2, T3, - and RI, R2,

R 3 - for the tangential and radial facesrespectively. The thin parts were dividedinto three parts, namely outside (To, Ro),middle (Tm,, Rm) and inside (T,, R,) .

The fibre form was examined according to

the standard practice.

Each sample of crystallinity was crushedinto powder with 80-100 mesh. The powderwas dried over phosphorus pentoxide invacuum at room temperature. Five hundredmg of the mixed powder was taken, pressedinto tablet, and used for the x-ray measure-ment of crystallinity.

Results and Conclusion

The results (Table 1) (Fig. 1) show thataverage fiber length of bamboo is about 2mm, average diameter is about 10.5-15.3 urn,double wall thickness is about 8-13.64 urn,and the ratio of length to breadth is over 100.

The fiber length of P. pubescensincreases and the relative crystallinitydecreases respectively with increasing age ofthe plant. In bamboos older than one year,the lignin content remains stable or risesslightly with years. The main structure, com-posed of cellulose fibers, are formed at anearlier period. Cell-wall growth and lignifica-tion proceed gradually.

Bamboo grows to full size within about 2-3 months, but it needs about 3 years for com-plete maturation of tissues. It means thatbamboos that complete their growth and rota-tion at the end of this period or stage is consi-dered satisfactory.

It is concluded that the study of fibrelength variations would help to determine theperiod of harvest and recycling.

247

Table 1. Change on Fibre Form and Crystallinity of P. pubescens of Different Ages.

Age Sample

OuterBase M i d d l e

Inner

Outer6 months Middle Middle

Inner

TopOuterM i d d l eInner

BaseOuterM i d d l eInner

1 yearOuter

Middle MiddleInner

TopOuterM i d d l eInner

BaseOuterM i d d l eInner

3 yearsOuter

Middle MiddleInner

TOP

OuterM i d d l eInner

BaseOuterM i d d l eInner

7 yearsOuter

Middle MiddleInner

TopOuterM i d d l eInner

Length (urn) Width (urn) Thickness of Re la t i ve2 walls (urn) Crystallinity

x 5’100 (%)X

196216661474

174216281612

150614361566

218623061790

193620841850

178419421838

207821361874

191721401908

203222442098

200020802054

232823822380

220821372136

417.4 21.3 13.6 3.39 25.0 10.1 3.39 33.7 149373.4 22.4 13.6 4.39 32.3 9.2 3.57 39.0 123524.0 35.6 12.0 2.44 20.3 8.0 2.71 34.0 123

709.7 40.7 14.3 3.20 22.4 10.8 3.34 30.8 122631.8 38.8 14.0 3.78 27.0 10.6 2.46 23.2 116 6 3655.5 40.7 13.4 3.08 23.0 9.9 2.65 26.9 120

606.6 40.3 12.1 3.30 27.2 10.0 2.93 29.5 124628.7 43.8 12.9 3.47 26.9 10.8 3.11 28.9 111655.8 41.9 12.5 3.08 24.7 10.8 2.97 27.5 125

699.6 32.0 14.5 4.02 27.7 12.6 3.83 30.3 150716.1 31.1 15.3 4.01 26.2 13.6 3.76 27.5 151508.4 28.4 13.9 4.05 29.2 12.3 3.87 31.4 129

554.3 28.6 13.8 3.10 22.5 12.2 3.02 24.8 140679.2 32.6 13.8 3.37 24.5 11.8 3.17 26.9 151 6 0639.6 34.6 13.0 2.77 21.1 11.4 2.59 22.8 141

520.0 29.2 10.5 2.64 25.2 9.1 2.53 27.9 170507.9 26.2 11.8 3.00 25.5 10.0 2.88 28.9 165550.7 30.0 10.8 3.27 30.3 9.1 3.27 35.7 170

540.0 26.0 13.9 3.27 23.5 12.1 3.14 25.9 149547.3 25.6 11.5 2.82 24.6 9.8 2.82 35.5 186505.8 27.0 11.7 2.38 20.3 10.0 2.36 23.7 160

603.1 31.5 14.8 2.67 18.1 12.9 2.65 20.6 130594.5 27.8 12.6 2.88 22.8 11.1 2.97 26.7 169 5 8424.2 22.2 11.7 2.30 19.7 10.1 2.26 22.5 163

623.8 30.7 12.7 2.68 21.2 10.9 - - 1 6 0572.9 25.5 12.1 2.56 21.1 10.5 2.53 24.2 185576.9 27.5 11.3 2.51 22.3 9.7 2.48 25.5 186

562.8 28.1 12.1 2.65 22.0 10.5 2.64 25.2 1166603.1 29.0 11.2 2.28 20.3 9.6 2.23 23.4 186583.2 28.4 11.3 2.37 21.0 9.7 2.25 23.3 182

639.2 28.6 12.6 2.82 22.5 10.8 2.86 26.3 185593.1 24.9 12.0 2.68 22.3 10.4 2.59 24.8 198 5 5579.6 24.4 12.0 2.74 22.9 10.3 2.71 26.2 199

526.8 23.9 12.0 2.74 22.8 10.5 2.68 25.6 184464.7 21.8 13.2 2.99 22.7 11.6 2.94 25.3 162472.8 22.1 12.0 2.52 21.0 10.3 2.35 22.8 178

2 4 8

Fig. 1. Change of fiber length of Ph. pubescens of the different age to the various height and part.

Length (mm) O-Outer, M-Middle. I-Inner

2.5

2.0

1 . 5

1 . 0

0.5

0

Base Middle TOPAge (1) 6 months

Base Middle Top(2) 1 year

Base Middle Top(3) 3 years

Base eMiddl

(4) 7 years

Fig. 2. Change of fiber length of Ph. pubescens of the same part at different ages.

Length (mm)

2 . 5

2.0

1 . 5

1 . 0

0.5

0

Base Middle TOP Base Middle Top Base Middle(1) Outer (2) Middle (3) Inner

TOP

249

The Mechanical Properties of BambooJules J. A. Janssen

Technical University, Eindhouen, Post Pus. 513,

5600-Eindhoven. The Netherlands

Abstract

Bamboo is compared with steel, concreteand timber in terms of the energy needed forproduction, safety, strength and stiffness aswell as simpleness of production as a con-struction material. The outcome of the com-parison places bamboo well ahead for con-struction purposes.

Introduction

Bamboo cornpares well and favourablywith other building materials like steel, con-crete and timber over energy requirementsduring construction, strength and stiffness perunit area of material, ease and safety of use.To a great extent the versatility of bamboo islargely due to its anatomical structure whichcontributes to its mechanical properties.

1. The anatomy and the properties ofbamboo:Bamboo has promising mechanical pro-

perties, To understand this it is important tostudy its anatomical and morphological char-acteristics. In a circular cross-section bamboo

is hollow. For structural uses this form hasmany advantages in comparison to a massiveand rectangular cross-section (e.g. wood).Bamboo needs only 57% material whenused for beam, and only 40% when used as acolumn. However, because of its taperedform bamboo is not viewed with favour byengineers - as the tapering causes a strengthloss between 35-40%. In building structuresbeams and columns with the same strengthalong the full length are needed. But on care-ful examination this fact seems to be exag-gerated because bamboo retains much of itsstrength in spite of the taper by the manner inwhich vessels and materials are distributedfrom top to bottom, e.g. a quarter scleren-chyma tissue more at the top than in thebottom of the culm (32% in the bottom, 41%at the top).

In the final analysis, there may be a totalloss of about 15% only. The disadvantagedoes not disappear, but its influence is muchless than many people fear.

The next factors affecting mechanical pro-perties are the nodes and the diaphragms ofthe culm. These have a structural function in

support, especially when two culms jointogether (Fig. 1).

2 5 0

At internodes the structure seems weaker.But the influence of diaphragms on thebending behaviour is still unknown. In Eind-hoven we have carried out bending tests onfull culms with and without diaphragms. Thedetailed analysis is still being carried out -the first impression shows no significant dif-ferences.

The outer skin of bamboo has a consider-able amount of silica. It improves the naturaldurability but preliminary studies indicate thatthe mechanical strength of the culm is nottignificantly affected by its absence.

Bamboo is a composite. In mechanics acomposite is a material composed of soft andweak material, stiff and strong material, Inbamboo the former is cellulose and the latterlignin.

Other well known examples are rein-forced concrete and glass fibre polyester. Inmaterials-science composites are well knownfor their good properties, the properties of thewhole being better than the sum of the com-ponent parts. The distribution of the cellulosein the cross-section of the wall of a culm con-tributes to the quality of strength of thematerial. On the outside the percentage ofcellulose is as much as 60%, decreasing to a20% on the inside. From a mechanical pointof view the material on the outside is far moreeffective. As a result, the strength and stiff -ness of a bamboo culm is better than in a casewhere cellulose is distributed equally. Thoughthe chemical composition of wood and

bamboo do not differ very much, bamboo istwice as good in stiffness than wood. Thereason for this is not known yet; the besthypothesis is the angle between the cellulosemicrofibrils and the cell-axis, being 20o forwood and only 10o for bamboo. Bamboodoes not have any rays. A ray is a weak spot,because it serves transport and storage offood. As a result, bamboo is far better in shearthan wood, contrary to the general opinion.This last statement, however, is based on thethickness: 6 or 7 mm is normal for bamboo,but unheard of for wood.

2 . The advantages of bamboo as abuilding material:How does bamboo compare with three

other common building materials: concrete,steel and timber? Evidently, such a compari-son can only be rough and difficult as well,because each of these four cons is t s anumber of different variables. Given in thesubsequent paragraphs are four factors forwhich comparisons are made. These are:

a. The energy needed for production:Energy has to be expended to produce anymaterial, In the case of fabricating structuralelements for the construction industry energyhas to be used to produce a beam or column.One can measure the benefit of prodycing acolumn with different materials by workingout amounts of energy needed to handle acertain amount of load. The energy neededfor four constructing materials is given belowin the table.

Table 1. Energy needed for production compared withstress when in use.

Material

(1)

Energy for Weight per Energy for Stress Rat io energyproduc t ion volume produc t ion when in u se pe r un i tMJ/kg kg/m3 MJ/m3 N/mm2 stress

(2) (3) (4) (5) (4)/(5)

Concre te 0.8 2,400 1,920

Steel 30 7,800 234.000

Wood 1 . 600 600

B a m b o o 0 . 5 600 300

Energy, needed for product ion, compared wi th s t ress when in use .

8 240

160 1.500

7.5 80

12 25

251

In column (2) data about energy is givenwhich can be found in several handbooks onmaterials technology. The energy for wooddeals with logging, sawing and transport, andthe energy for bamboo with harvesting andtransport only. Columns (3) and (4) areneeded to obtain data on energy per volume,to be compared with the stresses in column(5). The result, the ratio between the energyfor production and the stress in the material,is given in column (6).

It is seen from the last column that perequal unit of load bearing capacity, bamboorequires the least energy for its production.Timber is the second, reinforced concrete thethird, and steel requires the most. Thesefigures are not exact, they give only an orderof magnitude. We can see, however, thatsteel and concrete make a heavy demand ona large part of the energy resources of the“missile” earth, contrary to wood andbamboo.

In fact, this table should be enlarged withthe lifetime of the materials concerned, butthen the energy demand of the severalmethods of preservation should be added aswell.

Due to the fact that the energy in the pro-duction process is an important component ofthe price, it is tempting to state that bamboo isa very cheap building material, however thisassumption i s too simplistic and thetemptation has to be avoided.

b. The safety of the material: Bamboo isconsidered generally a safe building material.Its capacity to survive an earthquake or ahurricane is well known. This capacity can berelated to two mechanical properties.

i. The strain energy, i.e. the energystored into the material during load bearing.The strain energy is defined as the surface ofthe stress-strain-diagram

f o r c e o r s t r e s s

, co1 l a p s e

Fig. 2 Stress-strain diagram

d e f o r m a t i o n o r s t r a i n

2 5 2

A test on building materials results in adiagram, representing the relationshipbetween the force, acting on the material, andthe deformation of the material. The surfacebelow this diagram represents the energy,

‘stored in the material. (Fig.2)

The area, shaded vertically, representsthe situation of a normal use of the material ina building,while the area,shaded horizon-

tally, represents the situatjon of a collapse.Evidently, the ratio between the two areas isan estimation for the safety of the material.Calculations of this ratio show:

concrete 10steel 1400wood 20bamboo 50

This means that from a safety point ofview, steel is safest, bamboo second, woodthe third and concrete last.

ii. A -second property deals with thedeviation in the strength. Deviation means:when testing a building material, some speci-mens will behave very well, while othersbehave worse. The test results appear to bescattered around the mean value. In the caseof steel, a well-controlled product, thisscattering is very small and the allowablestress o can be about 60 percent of the meanstrength om:

And the behaviour of concrete is inbetween these.

On the contrary, in the case of naturallygrown products like wood and bamboo, thescattering is very wide, and consequently (toavoid the use of a bad specimen in a building)the allowable stress 'o ' , is only a 15 percent ofthe mean Strength om:

During an earthquake,cyclone,or any similar disaster, the stress in any building willincrease, leaving from ‘o’, being the normal

situation. In the above diagrams it can be seenthat steel will collapse rather quickly, followedby concrete, with wood and bamboo in thelast (and best!) place.

c. The strength and the stiffness per unitof material: In construction the strength andstiffness of a material is important. This can bemeasured by calculating the ratio betweenallowable stress and the mass per volume.Given below are figures for:

concrete 0.003steel 0.020wood 0.013bamboo 0.017

in which bamboo appears to be the bestone with respect to strength.

As to stiffness, the ratio between theYoung’s modulus and the mass per volume isused. (Figs. 3-5)

area of scattering

area of scattering

Fig. 3. Strength tests on (a) steel and (b) wood and bamboo

253

Taking all four together:

s t e e lr

0m

concrete

I

wood/bamboo

.

area of s c a t t e r i n g

Im

a r e a o f s c a t t e r i n g

Fig. 4. Behaviour of steel, concrete wood and bamboo to stress.

concrete 1 0steel 27wood 1 8bamboo 3 3

from which bamboo appears to be the best.

d. The simpleness of production: Thisaspect seems to be more “soft” than the threementioned ahead; for the people who usebamboo, however, it is as important.

a. Building with steel and concrete does notbelong to the normal possibilities forvillage people, in contradiction to woodand bamboo. However, in the case ofwood one has to wait many years, but inthe case of bamboo one can harvest theripe culms each year.

b. An environmental advantage: in the case

of wood a whole area is cut at once, butin the case of bamboo only the ripe culmsare cut, while the younger culms (themajority!) are left. For the micro-climateand the environment this yearly partialcrop is much better.

Due to its circular and hollow shape, onlysimple tools are needed for its croppingand use. With bamboo there is no sawingor logging like in the case of wood; wastematerial like bark and sawdust is unheardof.

Bamboo is represented by many botan-ical species, each with its own pro-perties. As a result one can find anappropriate bamboo for a variety of pur-poses.

I I I

I,50 m 1,50 m I,50 m

Fig. 5. Bending of bamboo culm

254

Fig.

3. The long term behaviour of bamboo Such tests have been carried out in theunder load: Eindhoven Bamboo Laboratory for the past

Laboratory tests on the mechanical pro- three years (1982 - 1985). Tests have been

perties of bamboo are usually short-term carried out concerning the bending of

tests. Building, however, is a long-term bamboo culms, as follows:

activity, and consequently we need long-termtests to learn about the long-term behaviour.

Bambusa blumeana from the Philippineswas obtained for the study and factors like

60

Fig. 7. Creep deformation

I s t r a i n

I

time t

300D a y s

255

diameter, thickness of wall, mass per volume,fibre content and the angle betweenmicrofibrils and cell axis were taken intoaccount. Samples were subjected to the testwith and without diapraghms and outer skinwith an m.c. of 8 and 12% with the ambientRH at 60 or 80%.

The load was applied in such a way thatthe initial strain was 2 pro mille. Creep andrecovery were studied during eight to sixweeks each and this was carried out fourtimes. Unfortunately, the analysis has notbeen completed and preliminary trends canbe seen. (Figs. 6. 7)

Firstly: creep and recovery in bamboo canbe described with a Burgers-model, asfollows:

in which:

6 is the applied stress, kept constant.6El

is the immediate deformation, theimmediate strain; the cellulose actingas a spring; this strain is elastic, it dis-appears with the load; it happens in

the crystalline part of the cellulose.6

E2is the creep, the increase of strain withtime.

nl is a viscous component, symbolized asa dashpot; it is a plastic deformationcaused by a sliding between cellulosechains in the amorphous part of thecellulose, and by a deformation in theamorphous lignin; this strain dis-appears with the load.

n2 i s t h e permanent deformation,remaining after removal of the load.

The use of this mathematical model is tocalculate the said E’s and n’s as physicalproperties.

Secondly, the deformation which remainsafter removal of the load, is for bamboo only5 to 10 percent of the immediate deforma-tion, to be compared with 50 to 100 percentin the case of wood. For practical purposesthis is wonderful; detailed analysis has to bedone to test the data for scientific rigour.

256

Physico-Mechanical Properties andAnatomical Relationships of Some

Philippine BamboosZenita B. Espiloy

Forest Products Research and Development Institute,NSTA, College, Laguna 3720, Philippines

Abstract

T h i s r e p o r t i n c l u d e s t h e physico-mechanical properties and anatomical char-acters of Bambusa blumeana and Gigan-tochloa levis. Physico-mechanical proper-ties such as relative density, shrinkage, mois-ture content, static bending and compressionparallel to the grain were correlated to anato-mical characteristics, e.g., fibrovascular bundlefrequency and dimensions of f iber and vessel.Results showed that there is an increase incompressive and bending strengths towardsthe top portion of the culm of both species. Thistrend could be attributed to the significant in-creases in relative density and fibrovascularbundle frequency.

Introduction

Housing is one of the basic needs of man.The pressures of population on the dwindlingsupply of commonly used timbers for housingcalls for research and development efforts onthe use of non-timber forest products, particu-larly bamboo. Certain aspects of the propertiesand use of these resources have beenneglected. If studied, the results may help theefficient use of bamboo materials for housingcomponents.

A knowledge of the physical and mechan-ical properties in relation to the anatomicalcharacteristics of erect bamboo is necessary inassessing its potential uses as building materialfor housing, furniture making and for generalconstruction work and in converting it to avariety of finished products. Furthermore, thedifferent properties of this resource will not

only serve as a basis for promoting its accep-tance but also for improving its marketpotential.

Several studies on characteristics and pro-perties of B. blumeana and G. levis wereundertaken (Tamolang et al., 1980). Velas-quez and Santos (1931) studied five speciesof bamboos and claimed that B. blumeana wasone of the most common and widely distri-buted bamboos in the Philippines, occurring incultivation throughout settled areas at lowaltitudes.

B. blumeana was purposely introducedfrom Malaysia during pre-historic times(Merrill, 1916). It is, by far, the most valuableand popular species of bamboo used for con-struction in rural areas. The stem of B.blumeana consists of a hollow culm withdistinct nodes and internodes. It grows from 10to 25 m high and reaches a diameter of 80 to150 mm. It is erect, nearly straight from thebase’upward and gently bending ata the top.The basal portion of the clump is surroundedby a dense thicket, 2 to 3 m high, of spinybranches.

On the other hand, G. levis may be consi-dered as an exotic species (Merrill, 1916). Itgrows in certain areas of the Philippines andalso in dense forests, especially in moist placesin ravines or depressions near streams. Itsgeneral appearance resembles that of B.blumeana although its culm is stout, straightand smooth with very much less prominentnodes than B. blumeana. It reaches a height of10 to 25 m and a diameter of 100 to 200 mm.Brown and Fischer (1918) said that the stemsof this bamboo species are only used as pipesfor temporary water supply and for building

fish traps; rarely used for building operations,except for walls of houses, because they areespecially durable.

Bamboos, in general, belong to the Barn-.buseae tribe of the huge family Gramineae(Sineath et al., 1953)) characterized by hollowor rarely solid stems that are closed at thejoints or nodes. The anatomical structure ofthe two species considered in this reportwere studied (Velasquez and Santos, 1931;Grosser and Zamuco, 1971; Zamuco andTongacan, 1973). The compact fiber tissuesare present in the outer part of the culm,whereas the inner part is mostly of parenchymacells. A study of B. blumeana (Espinosa, 1930)showed that for all engineering purposes, aculm about 300 mm in circumference, whenloaded at the center on a span of 1.52 m cansupport 500 kilograms weight. When used as apost or column of about 1.22 m, it can support4,000 kg.

Espiloy (1979, 1983) studied the vari-ability of specific gravity, silica content andfiber measurements in B. blumeana; a strongpositive correlation was found to exist betweenspecific gravity and cell wall thickness and silicacontent. The anatomical structure of the bam-boo culm is the basis for understanding thephysical properties of bamboo, and is respon-sible for specific gravity, silica content and fiberdimension to vary across and along thebamboo culm.

The chemical properties and eating qua-lities of shoots of three ages (7, 10 and 15days after emergence) of B blumeana, G.leuis and four other species were studied(Gonzales and Apostol, 1978). Chemicalanalysis of the nutrient components showedthat age level had no effect on nutrient con-tent. Results of a taste test disclosed that15 day-old B. blumeana shoots were the mostacceptable as far as colour, texture and tasteare concerned.

Escolano et al. (1964) found B. blumeanasuitable for pulp and paper making and thatthis species yields good quality bond, airmailbond, onion skin, offset book, kraft, wrappingand bag papers. Likewise, Semana (1967)found the same species to be a suitable rawmaterial for kraft pulps due to its pulp strength,pulp yield and acceptable level of silicacontent.

Bamboos. are very susceptible to theattack of decay fungi and powder-post

beetles, particularly Dinoderus minutus Fabr.(Casin and Mosteiro, 1970). The presenceof starch in bamboo contributes to i tssusceptibility to beetle attack (Liese, 1980). Atentative classification showing the naturalresistance of some bamboo species to fungalattack was made (de Guzman, 1978), basedmostly on percentage weight loss of speci-mens after four months of exposure. B.blumeana and G. leuis were consideredmoderately resistant.

Present Studies: In the present studies,the author determined the effect of fibro-vascular bundle frequency, culm, wall thick-ness, diameter and length or span of materialon the different physical and mechanical pro-perties along the culm length. The interrela-tionships of the different physical andmechanical properties in relation to theiranatomical characteristics within and betweenspecies were also evaluated to ascertain theirsuitability for various uses, especially inhousing.

Five culms each of three-year old B.blumeana and G. leuis were used in thisstudy. The culm length, diameter, length andnumber of internodes per culm wererecorded. Representative sections of the butt,middle and top portions were cut into seg-ments comprising of eight whole-length inter-nodes. The segments and internodal sectionswere number-coded to indicate their originalpositions in the culm. Each eight-internodalsection was further cut for use in the differenttests. In general, the standard test procedureof the American Society for Testing Materialsfor small clear specimens of timber wasfollowed for determination of physical andmechanical properties. The data obtained arethe average properties of the material in greencondition. The frequency of fibrovascularbundles per unit area was determined directlyusing a calibrated magnifier, “Scale lope” at20 x magnification. The length, width, lumendiameter and cell wall thickness of fibers andvessel length and diameter were determined,

Physical and Mechanical Properties:Culm height, number of internodes per culm,length and diameter of internodes, and culmwall thickness of Bambusa blumeana andGigantochloa leuis are presented in Table 1.B. blumeana has longer and more internodesper culm and thicker culm walls than G. leuis;the latter is taller and the diameter of its inter-nodes is bigger than the former. The average

258

Table 1. Physical data for culms of B. blumeona and G. leuis collected in Bayog, LOS Banos.Laguna and Nagcarlan, Laguna, respectively.

SpeciesProperty B. blumeana G. leuis

(Kauayan-tinik) (Bolo)

1. Culm height (m) i2.9 14.9

2. Number of internodes per culm 40.0

3. Internode length (mm)a) Buttb ) Middlec) Top

Average

4. Internode diameter (mm)a) Buttb ) Middlec) TOP

Average

5. Culm wall thickness (mm)a) Buttb ) Middlec) TOP

Average

284.00 200.4432.7 455.4321.0 264.8345.9 306.9

101.4 121.280.5 94.141.0 40.074.3 85.1

19.4 12.29.1 8.76.3 5.8

11.6 8.9

Table 2. Average physical and mechanical properties of B. blumeana and G.. leuis.

S p e c i e sProper ty

B. blumeano (kauayan-tinik) G . levis (Bole)

Bu t t Middle Top Average But t Middle TOP Average

1. Moisture Content (%) 1 9 4 . 7 114.0 98.8 135.8 143.0 1 1 5 . 1 93.8 117.3

2. Re la t i ve Dens i ty ’ 0.388 0.537 0.585 0.503 0.474 0.539 0.610 0.541

3. Shrinkage (%)

a) Thickness 1 6 . 6 1 3 . 3 10.0 13.3 1 2 . 9 11.3 8.9 1 1 . 0

b) Width 12.0 6.2 4.8 7.7 8.0 6.5 5.2 6.6

4. Compression Parallel to Grain.

Maximum crushing strength (MPa)

a) Nodal 34.7 37.2 37.3 36.4 37.7 41.9 44.3 41.3b) Internodal 35.9 39.5 39.5 38.3 38.7 41.7 43.4 41.3

5. Static Bending’

a) Stress at proportional limit (MPa) 29.5 20.2 1 8 . 2 22.6 1 7 . 6 1 4 . 9 1 8 . 6 17.0b) Modulus of rupture (MPa) 43.2 28.4 24.7 3 2 . 1 25.4 1 9 . 6 2 6 . 1 23.7c) Modulus of elasticity (1000 MPa) 8.9 8.8 9.2 9.0 8.9 10.4 1 1 . 0 1 0 . 1

Based on volume at test and weight when oven-dry ! From green to oven-dry condit ion Tested at green condition.

results of the different physical and mechan- variance based on the mean squares and sta-ical properties of the two bamboo species are tistical significance of physical and mechanicalgiven in Table 2. The summary of analyses of properties of the two species is shown in

2 5 9

Table 3. Summary of analyses of variance on physical and mechanical properties ofB. blumeana and G. levis.

Mean Squares and Statistical Significance

Physical Properties Mechanical Properties

Shrinkage Static BendingSource of CompressionVariation parallel to

Moisture Relative grain Stress at Modulus of Modulus ofContent Density Thickness Width (maximum Proportional rupture elasticity

crushing limitstrength) (SPL) (MOR) (MOE)

Treatment(Butt. Mid, Top) 51129.90’ 0.3321’ 243.09’ 239.38’ 5443.019” 10884.936ns 32240.700ns 300 .237” ’

Block (species) 13038.32ns 0.0300ns 196.86ns 45.88”’ 24040.017” 24741.482”’ 55126.533”’ 908.900ns

cv (X) % 63.88 29.60 68.50 80.12 3 . 9 7 48.67 5 4 . 3 5 17.26

! Signif icant at 95% level o f probabi l i ty! " S ign i f icant a t 99% leve l o f probabi l i tyns Not significar

Table 3.

For both species, moisture content andshrinkages on thickness and width decreasedtowards the top while their relative densityvalues increased towards the top. Resultsshow that there is a significant difference in allthe physical property values investigated atthree height levels but none between species.There was a general trend of increasingmaximum crushing strength (MCS) valuesfrom butt to top portions which was foundhighly significant at three height levels andbetween species. On the other hand, therewas no distinct trend in bending properties,i.e., stress at proportional limit (SPL),modulus of rupture (MOR), and modulus ofelasticity (MOE) although most of the higheststrength values were observed at the topportions. However, such differences in bend-ing properties at three height levels and

Table 4. Some anatomical properties and characteristics of B. blumeana and G. leuis.

Property

1. Fibrovascular bundle frequency(No. per sq. mm)

2. Fiber dimensions (mm)

a) Fiber length

b) Fiber diameter

c) Lumen diameter

d) Cell wall thickness

3. Vessel dimensions (mm)

a) Vessel length

b) Vessel diameter

Species

B. blumeona (kauayan-tinik) G. levis (Bolo)

B u n Midd le Top Average Butt Middle Top Average

1 . 7 4 3 . 1 2 3 . 8 0 2 . 8 9 1.11 1.50 2 0 6 1.56

2 . 5 0 2 . 5 5 2 . 6 3 2 . 5 6 1.88 1.52 2 . 0 5 1 82

0.0148 0.0152 0.0142 0 . 0 1 4 7 0.0165 0.0155 0.0159 0 0160

0.0046 0.0032 0.0034 0.0037 0.0056 00036 0 . 0 0 6 5 0.0052

0.0052 0 . 0 0 6 1 0.0054 0.0056 0.0060 0.0058 0.0059 0.0059

0.8228 0.7068 0.8294 0.7863 1 . 1 3 0 5 0.6776 0 5 9 5 7 0 . 8 0 1 3

0.1862 0.1366 0.1736 0.1655 0.2310 0.2308 0.1989 0 . 2 2 0 2

260

between species were found insignificant. Asin wood (Heck, 1956) the strength propertiesin bending of bamboo are correlated withspecific gravity or relative density.

Anatomical Properties and Charac-teristics: Some anatomical properties andcharacteristics of the two species which includefrequency of fibrovascular bundles and dimen-sions of fibers and vessels are shown in Table4. B. blumeana averaged higher than G. leuisin fibrovascular bundle frequency, but theirrespective values increased from the butttowards the top portion. G. leuis averagedhigher than B. blumeana in all vessel and fiberdimensions, except for fiber length. Asummary of analyses of variance based on

Table 5. Summary of analyses of variance on some anatomical properties andcharacteristics of B. blumeana and G. levis.

Mean Squares and Statistical Significance

Fiber dimensions Vessel dimensionsSource of Variation Fibrovascular

bundle Fiber Fiber Lumen Cell wall Vessel Vesselfrequency length diameter diameter thickness length diameter

Treatment (Butt. Middle, Top) 179.681” 0.238ns 3.22gns 19 769’ ’ 0.420’ 1496.542” 43.972ns

Block (Species) 837.801” 4 .019” 43 .471” 17.170” 6.914” 4945.081” 1314.614”

cv (X) % 56.55 1 4 . 4 9 26.85 38.09 5.49 20.64 24.33

ns - Not significant

’ * - Significant at 99% level of probability

mean squares and statistical significance of highly significant except for length and dia-their anatomical properties and characteristics meter of fiber and diameter of vessel (Tableis shown in Table 5. 4).

Results show that differences in fibro-vascular bundle frequencies at three heightlevels and between species were found highlysignificant. Likewise, almost all fiber andvessel characteristics and properties betweenspecies and in three height levels were found

Correlation of Physical and Mechan-ical Proper t i e s with AnatomicalStructure: The physical and mechanicalproperties of the two species which werecorrelated with their respective anatomicalstructure are shown in Tables 6 and 7.

Table 6. Correlation coefficients of different physical and mechanical properties withsome anatomical structure of B. blumeana.

Fibrovascularbundlefrequency

Moisture content 0.035

Relative density -0.017

Shrinkage (thickness) -0.182

Shrinkage (width) -0.633’

Maximum crushing strength 0 . 1 2 1

Stress at proportional limit 0.063

Modulus of rupture 0 . 1 2 1

Modulus of elasticity 0.716’

* Significant at 95% level of probability

Fiber Fiberlength diameter

0.2% 0.290

- 0.272 -0.186

-0.162 -0.126

-0.193 0.003

- 0.310 -0.181

0.535’ 0 . 5 1 7

0.468 0.417

-0.177 0.043

Lumendiameter

0 . 3 4 7

- 0.331

-0.268

- 0.208

-0.262

0.492

0 . 4 1 7

-0.067

Cell wallthickness

0.035

0.111

0.079

0 . 1 8 8

- 0.060

0 . 2 4 3

0.154

-0.130

Vessel Vessellength diameter

- .014 0.025

0.363 0 . 4 6 3

- 0.059 - 0.010

0 . 0 7 2 0.025

10.103 0 . 3 0 7

0 . 1 8 8 -0.003

0.317 -0.221

-0.068 -0.256

Table 7. Correlation coefficients of different physical and mechanical propertieswith some anatomical structure of G. levis.

Moisture content

Relative density

Shrinkage (thickness)

Shrinkage (width)

Maximum crushing strength

Stress at proportional limit

Modulus of rupture

Modulus of elasticity

Fibrovascularbundlefrequency

-0.170

0.110

- 0.366

-0.528’

0.020

-0.530’

-0.510’

- 0.080

Fiber Fiberlength diameter

-0.130 0.080

0.180 - 0.080

0.095 0 . 0 1 1

0 . 1 3 1 0.199

0.270 0.060

-0.810’ 0.420

- 0.220 0.250

-0.090 0.160

Lumen Cell walldiameter thickness

0.310 -0.100

- 0.260 -0.080

-0.027 0.110

0.217 0.023

- 0.810’ 0.170

0.490 -0.100

0.460 -0.103

0.130 0.004

Vessel Vessellength diameter

0.230 0 . 3 2 0

-0 .18 -0.270

0.446 0 . 1 5 4

0.366 0.219

-0.480 -0.280

- 0.245 0 . 2 4 0

- 0.230 0.290

-0.130 - 0.003

! " Signi f icant a t 95% leve l o f probabi l i ty261

Table 8. Correlation coefficients of physical characteristics of specimens withcompressive and bending properties of B. blumeona and G. leuis.

B blumeana (Kauayan-tinik) G levis lBolo)

Comprerssion

parallel to grain Static bending Static bending

Physical Maximum Stress at Modulus M o d u l u s Maximum Stress at Modulus ModulusCharacteristics crushing Relative proportion of of Relative crushing Relative p r o p o r t i o n - o f of Relative

of Specimen strength density al limit rupture elasticity density strength density al limit rupture elasticity density

Outside diameter -0.230 -0.208 0.081 0. .081 -0.260 -0.293 -0448. -0434. -0 124 -0.230 -0363 -0.789'

Length/Span -0.290 -0.436 0.081 0.080 -0 . 261 -0 . 293 -0668’ -0.441’ -0.125 -0.230 -0.362 -0.790.

Culm wall thickness -0.290 -0.436. 0.617’ -670* -0 175 -0462 -0.668' -0.441* -0.120 -0 .163 -0.795' -0615'

‘S ign i f icant a t 95% leve l o f probabi l i ty

In B. blumeona (Table 6), fibrovascularbundle frequency is negatively correlated withshrinkage on width of specimens (r =- 0.528*), stress at proportional limit (r =-0.530*), and modulus of rupture (r =-0.510’). This means that an increase infibrovascular bundle frequency towards thetop port ion of the culm may result indecreased shrinkage on width, stress at pro-portional limit and modulus of rupture values,as can be seen in Table 2.

There was also a negative correlationbetween stress at proportional limit and fiberlength (r = -0.810’) and between maxi-mum crushing strength with lumen diameter(r = -0.810’). This implies that decreasedstress at proportional limit towards the topportion may be due to increased fiber lengthand that an increased maximum crushingstrength towards the top may’ be due todecreased lumen diameter resulting in thickerwalls, as can be seen in Tables 2 and 4.

On the other hand, the fibrovascularbundle frequency in G. leuis (Table 7) wasalso negatively correlated with shrinkage onwidth (r = -0.633’) of specimens but posi-tively correlated with modulus of elasticity (r= 0.716’). Stress at proportional limit wasalso positively correlated with fiber length (r= 0.535’). This implies that the increasedmodulus of elasticity towards the top portionis due to the increased fibrovascular bundlefrequency where decreased shrinkage alsooccurred. The length of fiber has somethingto do with the increased values in stress atproportional limit towards the top portion ofthe culm, as seen in Tables 2 and 4.

Correlation of Physical Character-istics of Specimens with Compressiveand Bending Properties: Table 8 showsthe correlation of outside diameter, length orspan and culm wall thickness of specimenswith compressive and bending properties ofthe two species. In B. blumeano, the length orspan and culm wall thickness with samevalues of (r = - 0.436’) were negativelycorrelated with relative density in compres-sion whereas the culm wall thickness waspositively correlated with bending propertiessuch as stress at proportional limit (r =0.617’) and modulus of rupture (r =0.670’). This means that as the culm wallthickness decreases towards the top, there is acorresponding decrease in stress at propor-tional limit and modulus of rupture whereincreased relative density also occurred(Table 2).

In G. leuis, the outside diameter, length orspan and culm wall thickness of specimenswere negatively correlated with maximumcrushing strength and relative densities bothin compressive and bending properties. Like-wise, there was also a negative correlationbetween culm wall thickness and modulus ofelasticity (r = -0.795’). This implies that adecrease in any of the physical characteristicsof specimens may result in a correspondingincrease in relative density and maximumcrushing strength of the materials (Table 2).

Conclusions andRecommendations

This study has disclosed some interestingfacts regarding the different properties of B.

blumeana and G. leuis.

262

Based from test results, B. blumeana wasfound to have a considerably lower relativedensity than G. levis which is associated withhigher moisture content and shrinkagevalues. G. levis was found to have a highermaximum crushing strength than the formerbut was weaker in bending strengths, exceptfor modulus of elasticity.

With regard to their anatomical structure,B. blumeana averaged higher than G. levis infibrovascular bundle frequency but lower in allfiber and vessel dimensions, except for fiberlength. Anatomically, relative density isregarded as a function of the ratio of cell wallvolume to cell void volume. As such, it isaffected by cell wall thickness and structure,cell width, the relative proportions of differenttypes of cells, and the kind and amount ofextractives present. Moreover, relativedensity is a measure of the strength propertiesof a material. The findings of other investi-gators were verified in this study. The generalincrease in compressive and bendingstrengths towards the top portion of the wholeculm could be attributed to the significantincreases in relative density and fibrovascularbundle frequency towards the same directionalong the culm length.

Similar studies on other bamboo speciesshould be undertaken. Further investigation isnecessary to confirm these findings, which atthis point can be considered preliminary. Thefindings must be interpreted with caution,since the results may not hold true for otherbamboo species growing in another site andsubjected to varying environmental con-dit ions.

References

Brown, W.H. and Fischer, A.F. 1918. Philip-pine bamboos. In: Minor Products ofPhilippine Forests, (Ed. Brown, W.H.).Bureau of Forestry, Department of Agri-culture and Natural Resources l(22) :251-310.

Casin, R.F. and Mosteiro, A.D. 1970. Utiliza-tion and preservation of bamboos. FOR-PRIDECOM Wood Preservation Report5(6): 86-92.

Escolano, J.O., Nicolas, P.M. and Tadena,Jr., F.G. 1964. Pulping, bleaching andpapermaking experiments for kauayan-

tinik (B. blumeana). Philippine Lum-berman 10(4) : 33-36.

Espiloy, Z.B. 1979. Effect of internode heightto fiber length, specific gravity andmoisture content of B. blumeana. FOR-PRIDE Digest 8(3 & 4) : 83-85.

Espiloy, Z.B. 1983. Variability of specificgravity, silica content and fiber measure-ments in kauayan-tinik (B. blumeana).NSTA Technology Journal 8(2): 42-74.

Espinosa, J.C. 1930. Bending and compres-sive strengths of the common Philippinebamboo. Philippine Journal of Science41: 121-135.

Gonzales, E.V. and Apostol, I. 1978. Chem-ical properties and eating qualities ofbamboo of different species. FinalReport, PCARR Proj. No. 283, Study 4.FPRDI Library, College, Laguna, Philip-pines.

Grosser, D. and Zamuco, Jr., G.I. 1971.Anatomy of some bamboo species in thePhilippines. Philippines Journal ofScience 100(l): 57-73.

Guzman, E.D. de. 1978. Resistance of bam-boos to decay fungi. Terminal Report,PCARR Proj. No. 283, Study 7, UPLB-CF Library, College, Laguna, Philip-pines.

Heck, G.E. 1956. Properties of some bam-boos cultivated in the Western Hemi-sphere. USDA Report D1765, ForestProducts Laboratory, Madison 5,Wisconsin, U.S.A.

Liese, W. 1980. Anatomy of bamboo. 161-164. In: Proceedings of a Workshop inSingapore (Bamboo Research in Asia).(Eds. Gilles Lessard and AmYChouinard). Organized by the Inter-national Development Research Centerand the International Union of ForestryResearch Organization.

Merrill, E.D. 1916. On the identity ofBlanco’s species of Bambusa. AmericanJournal of Botany 3: 58-64.

S e m a n a , J.A., E s c o l a n o , J . O . a n dMonsalud, M.R. 1967. The kraft pulpingqualities of some Philippine bamboos.TAPPI 50(8): 416-419.

Sineath, H.H., Daugherty, P.M., Nutton,R.N. and Wastler, T.A. 1953. Industrialraw materials of plant origin. Part V.

2 6 3

Survey of the bamboos. Georgia Instituteof Technology, Engineering Expt. Sta.Bulletin 18. Atlanta, Georgia.

Tamolang, F.M., Lopez, F.R., Semana, J.A.,Casin, R.F. and Espiloy, Z.B. 1980. Pro-perties and utilization of Philippine erectbamboos (Bamboo Research in Asia: Pro-ceedings of a workshop held in Singa-pore, 28-30, May, 1980) IDRC-159 A.

Ottawa, Ontario, Canada.

Velazquez, G.T. and Santos, J.K. 1931.Anatomical study on the culm of fivePhilippine bamboos. Natural and AppliedScience Bulletin l(4) : 281-315.

Zamuco, Jr. G.I. and Tongacan, A.L. 1973.Anatomical structure of four erect bam-boos.in the Philippines. The PhilippineLumberman 19( 10) : 20-23.

264

Diseases

265

Bamboo Blight in the Village Groves ofBangladesh

Mohammad Abdur Rahman

Forest Research Institute, P.O. Box 273,Chittagong, Bangladesh

Abstract

Bamboo blight is an important disease ofvillage grown bamboo in Bangladesh. Theblight first affects new culms but may also con-tinue into older ones. The symptoms of thedisease have been briefly described. Conio-thyrium fuckelii Sac. and Acremoniumstrictum W. Gams are commonly isolatedfrom blighted bamboo culms. The results of

isolation of fungi and pathogenicity tests are

presented. In the experiments performed A.strictum produces blight symptoms. Pre-viously infected culms s h o w a higherincidence of disease when compared to newculms which developed from healthy parentculms. pH of soil of bamboo clumps, carbonand nitrogen contents of bamboo culms are

not associated with the development andseverity of blight.

Various control measures have beenattempted which range from improued cul-tural practices to field tests with fungicides.Dithane M 45 is able to reduce the amount ofb l i g h t developing i n c u l m s . R e m o u i n gblighted bamboos, burning debris in situ andputting new soil in clumps significantlyincreased the survival of new culms.

Introduction

Bangladesh lies between 20.75o and25.75° North Lati tudes and 88.30° and92.75° East Longitudes. It has an area of143,997 square kilometres. The climate ofBangladesh is tropical. Summers are hot andwet, while the winters are cool and dry. Thetemperature varies from 52°F to 84°F inwinter and 70°F to 94°F in summer. Totalannual rainfall varies from 1,200 mm to

3,500 mm. Nearly 80 per cent of the annualrain falls between June and October. Humid-ity is generally high through most of the yearraising to almost 90 per cent in the rainy sea-son. Bamboo is an important economic cropin Bangladesh and of the 18 commerciallyuseful species described by Alam (1982),three are specially important. They areBambusa balcooa, B. Vulgaris and B. tulda.

Bamboo blight was first noticed in someparts of Rajshahi district. General informationon the symptoms and isolation of fungi asso-ciated with blighted bamboo tissues havebeen reported by Rahman and Ole Zethner(1971), Gibson (1975) and Rahman (1978).The latter also provided a review of reportedbamboo diseases. Pawsey (1980) includedsome historical background and importanceof the problem. Boa and Rahman (1983)reported the history of bamboo blight and itsepidemiology, described the disease andrecorded its etiology and on the spread of thedisease. Rahman and Khisha (1981) ascribedA c r e m o n i u m strictum W . G a m s a s apathogen which can cause bamboo blight.Rahman, Khisha and Basak (1983) reportedon some of the factors relating to regenerationand mortality of two bamboo species. Thispaper reviews earlier findings and reportsmore recent work on bamboo blight.

Symptoms Of Bamboo Blight

Mortality of bamboos, particularly those inthe village groves, mainly occur in two stages:i) mortality of very young emerging culmsgenerally within heights of 40 cm, and ii)mortality of newly growing culms which attainheights of about 1 m to 5 m. The former type

266

of mortality is very common (Rahman, Khisaand Basak, 1983; Banik, 1983) but the actualcause of mortality of emerging culms is notknown. Banik (1983) has suggested that eco-physiological conditions and genetic make upof each species and clump seem to influencethe rate of mortality of emerging culm in bam-boo. Mortality of growing culms, generallywithin heights of l-5 m, is by far the mostdamaging. The death of the small emergingculms, start as a light brown to brown dis-colouration of culm and culm sheaths. Dis-colouration may start either at the top or nearsoil level or along any side of the emergingculm. With the advance of discolouration anddecay, the culms fail to develop and ulti-mately rot and disintegrate. The symptoms ofthe blight of growing culms have beenreported (Rahman, 1978: Rahman andKhisa, 1981). Boa and Rahman 1983) andis covered more thoroughly by Boa, 1985 (inthis proceedings).

Isolation Of Fungi

Fungi were isolated from diseased Bam-busa balcooa collected from ChapaiNawabganj in Rajshahi (in the western part ofthe country) and also from Forest ResearchInstitute campus; and from B. vulgaris fromChittagong, on the eastern part of the coun-try, on Potato sucrose Agar or 2% Malt Agar

medium using standard phytopathologicaltechniques. Isolations of fungi from B.balcooa were from diseased (i) culm sheaths(ii) young culms (iii) older culms (iv) youngbranches (v) leaf sheaths and from healthybranches and culms. Details of the results ofisolation have been published elsewhere(Rahman, 1978; Rahman and Khisha, 1981).These isolations predominantly yieldedConiothyrium fuckelii Sac. But from blightedyoung branches and leaf sheaths of B.balcooa, and also from blighted older culmsand young branches of B. vulgaris, Acremo-nium strictum W. Cams, was most domi-nantly present. C. fuckelii was also isolatedfrom blighted older culms of B. oulgaris.Other isolates including Fusarium monili-formae Sheld, F. equiseti (Corda) Sacc.,Staehybotris bisbui (Sriniv.) Barron were iso-lated only to a lesser extent.

Pathogenecity Tests

Artificial inoculations with fungi C. fuckeliiS. bisbvi. A. strictus and F. moniliformae werecarried out on young culms of B. balcooa andB. Vulgaris. Inoculations were carried outwith or without any artificial injury on thehost. Spore suspension (S.S.) and artificiallyinfected bamboo blocks (1.B.B.) were used asinocula for pathogenicity tests.

The data in Table 1 reveal that inoculation

Table 1. Results of artificial inoculation of Bambusa balcooa in Rajshahi by Coniothdumfuckelii. Stachvboris bisbvi and Fusarium moniliformae.

Inoculantlnocula Part

type inoculatedTreatmentrepl icat ion

% infected

nodal interbud node

Coniothyium fuckelii S.S. culm sheath Inoculated - 40 3 0Control - 20 0 0

S.S. nodal bud Inoculated 22 50 50Control - 9 33 2 2

I.B.B. internode Inoculated - 25 24 28Control - 7 28 0

Stachybotris bisbvi I.B.B. nodal bud & Inoculated - 12 67 0internode Control - 4 25 0

S.S. culm sheath Inoculated 21 0 0Control - 7 0 0

Fusarium moniliformae S.S. culm sheath Inoculated - 15 0 0Control - 15 0 0

267

Table 2. Results of artificial inoculation of Bambusa balcooa and B. vulgaris in Chittagongby Acremonium stricturn !

BambooSpecies

State of growthof culms or

branches Treatment

No. of culms/branches

Inoculated Infected Symptoms

B. balcooa - Young branchfrom culmcutting inshade

InoculationControl

1 3 1 0 ” ’ Typical blight1 3 1 symptom

- Young branch Inoculation 1 2 8! ". + Typical blight

from culm Control 1 2 0cutting inthe open

B. vulgaris - Young culmsti l l coveredwith culmsheaths

Inoculation 25Control 25

13’6

Typical blightsymptom

* The data have been adapted from Rahman & Khisha (1981)

with either C. fuckelii. S. bisbui or F. monili-formoe did not show any significant infectionas compared to the controls indicating thatnone of these fungi was a primary pathogenof bamboo blight.

Development of symptoms and resultantblight of young growing branches fromground layered culm cuttings of B. balcooa

were severe when the host materials weregrown either in the shade or in the open. Inboth the cases, higher numbers of inoculatedbranches developed blight symptoms as com-pared to the corresponding controls. Artifi-cially infected branches also yielded A.strictum consistently. A significantly highernumber of the inoculated culms of B. vulgaris

developed infection as comapared to that ofthe controls. About one month after inocula-tion some of the inoculated culms were foundto have developed necrosis on the culmsheaths. Removal of some of the culmsheaths revealed that discolouration also ex-tended to the tender culm undernearth. A.

strictrum was retrieved from the infected culmand culm sheath. Such culms developed adead top within one month’s time renderingthe symptoms typical of bamboo blight(Rahman & Khisha, 1981).

In the present study A. stricturn has been

found to be a primary pathogen of blight of B.balcooa and B. vulgaris (Table 2). This fungus

has also been reported to cause leaf spot of

Fig in Louisiana (Tim 1941). stalk rot (Gupta

and Renfro 1972) disease of maize and leafrot of Betelvine in India (Singh and Jeshi1973), wilt of Chrysanthemum maximum inCalifornia (Chase, 1978, Chase a n dMunnecke 1980), stem necrosis of SunflowerIN Indiana (Richerson 1981), black bundle

disease of corn (Barnett and Binder 1973).brown stem rot of Soybean (Presley andAllington 1 9 4 7 ) . C h a s e a n d Munnecke(1980) also noted that the host plant had to

be stressed by excessive soil moisture or bythe onset of flowering to obtain symptomscomparable with those on field symptoms.Unlike A. stricturn infections of Maize (Rajuand LaI 1977) or C. maximum (Chase andMunnecke 1980). development of symptomsin bamboo was observed from the early stagesof culm growth. It is suggested that in the caseof bamboo blight, infections were soilborneand occurred before or during emergence ofnew culm through the soil.

Field Trials To Control BambooBlight

In a recent experiment six blighted clumpsof B. vulgaris in Chittagong were treated with

Copper oxychloride and five clumps withDithane M 45 (a complex of zinc and manebcontaining 20% managese and 2.5% zinc) assoil drench in late July 1984. Five almostsimilarly blighted clumps were kept untreated

268

Table 3. Effect of cultuml measures and fungicfdal treatments on the survival of newculms of bamboos.

Species(locality)

B. balcooa(Rajshahi)

Treatments

Blighted bambooscut and removed,debris burnt inclumps and newsoil added.

Number ofNumber of new culms % survival CV%

clumps Developed Survived

15 5 6 8 263 43.30’ ’ 28.90

B. vulgaris(Chittagong)

Blighted bambooscut and removed,and new soiladded.Controls

Soil drenchedwith Cupravit

Soil drenchedwith Dithane M 45Controls

5 1 2 0 3 5 29.17 39.49

9 3 3 8 9 9 29.29 21.77

6 305 9 1 29.84 68.11

5 188 1 0 1 53.72 36.74

5 1 7 2 3 4 19.77 56.65

and served as controls. The number ofhealthy and dead culms were observed atregular intervals from 3rd August, 1984 untilJanuary, 1985. The results of the aboveexperiments on the survivality of new culmsare presented in Table 3.

Cutting and removing blighted bamboos,burning the debris of clumps in situ and addi-tion of new soil to clumps promoted the pro-duction of higher number of surviving healthybamboos in comparision with that of the con-trols. Cutting and removing blighted bamboosand adding new soil to clumps (without burn-ing) had no significant effect on the survival ofnew culms. Hence, the significant increase inthe number of survival of new culms is mostlikely due to the direct and/or indirect effectof burning. The direct effect of burning mayresult in a reduction in the inocula potential ofpathogenic fungus which existed in the debrisor in the top few inches of soil. The indirecteffect may be due to the addition of ash in thesoil which might have acted as a manure.Drenching soils of the bamboo clumps whichhad bamboo blight with either Copper oxy-chloride or Dithane M 45 proved to be bene-ficial as compared to the control clumps.Dithane M 45 soil drench was better thanCopper oxychloride treatment. The differ-ence was not, however, significant because ofhigh variability among the clumps.

References

Alam, M.K. 1982. A guide to eighteenspecies of bamboos from Bangladesh.Bulletin 2 (Plant Taxonomy Series), 29pp; FRI, Chittagong.

Banik, R.L. 1983. Emerging culm mortalityat early developing stage in bamboos.Bano Biggyan Patrika, 12: 47-53, FRI,Chittagong.

Barnett, H.L. and Binder, F.L. 1973. Thefungal host parasite relationship. AnnualReview of Phytopathology, 11: 273-292.

Boa, E.R. and Rahman, M.A. 1983. Bam-boo blight in Bangladesh: an importantdisorder of bamboos. A bulletin, 24 pp.FRI, Chittagong.

Chase, A.R. 1978. New fungus associatedwith vascular wilt of Shasta daisy. Califor-nia Agriculture, 32: 21.

Chase, A.R. and Munnecke, D.E. 1980.Shasta daisy vascular wilt incited by Acre-monium strictum. Phytopathology. 70:834-838. !

Choudhury, M.R. 1984. A study on supplyand demand of bamboos and canes inBangladesh. A special study report pre-pared for FAO/UNDP Project B.G.B./78/100,69 pp, Dhaka.

original not seen.

2 6 9

Gibson, I.A.S. 1975. Report on a visit to thePeople’s Republic of Bangladesh, 28February, to 1 April and 13 to 17 April,1975, 1-29 pp. Overseas DevelopmentAdministration, London.

Gupta, B.M. and Reufro, B.L. 1972. Asso-ciative efforts of two fungi in the incite-ment of Cephalosporium stalk rot ofcorn’. Labdev Journal of Science andTechnology B 10: 80-82.

Pawsey, R.G. 1980. Report on -a visit to thePeople’s Republic of Bangladesh; 25 pp,Overseas Development Administration,London.

Piper, C.S. 1944. Soil and plant analysis,Interscience Publishers, New York.

Presley, J.T. and Allington, W.B. 1947.Brown stem rot of Soyabean caused by aCephalosporium. Phytopathology 37:681-682.

Rahman, M.A. 1978. Isolation of fungi fromblight affected bamboos in Bangladesh.Bano Biggyan Patrika, 7: 42-47.

Rahman, M.A. Khisa, S.K. 1981. Bambooblight with particular reference to Acre-monium strictum. Bano Biggyan Patrika,10: 81-93.

Rahman, M.A., Khisa, S.K. and Basak, A.C.1983. Some factors related to the regen-eration and mortality of two bamboospecies in Bangladesh. Bano BiggyanPatrika 12: 6-11.

Rahman, M.A. and Ole Zethner, 1971. Aninterim report on results obtained inForest Pathology Section from Septem-ber 1969 to August, 1971. ForestdaleNews 4: 45-48. FRI, Chittagong.

Richeson, M.L. 1981. Etiology of a late sea-son wilt in Helianthus annus*. PlantDisease Reporter 65: 1019-1021.

Stakman, E.C. and Harrar, J.C. 1057. Prin-ciples of Plant Pathology, Ronald Press,New York.

Singh, B.P. and Joshi, L.K. 1973. Studies onthe disease of Betelvine (Piper betle L.) inJabbalpur (M.P.). A new leaf rot incitedby Cephalosporium acremonium *,Science and Culture 39: 312.

Tim, E.C. 1941. A new leaf spot of Fig*Abstract in Phytopathology XXX: 771.

Yarwood, C.F. 1959. Predisposition521-562. In, Plant Pathology: anadvance treatise. Vol. I (Eds. Horsfall,J.G. & Dimond, A.E.), Academic Press,New York.

original not seen.

2 7 0

Fungal Diseases of BambooA Preliminary and Provisional List

Eric R. B o a

Forest Research Institute, Chittagong, Bangladesh.

Abstract

Information on the fungal diseases ofbamboo is collated and the importance of thediseases is discussed. The need for furtherwork is indicated and certain methods ofstudy are suggested.

Introduction

This is the first attempt to collate informa-t ion on fungal diseases of bamboo asrecorded throughout the world. In practice,this will refer largely to countries in Asia, parti-cularly India and Japan; only a limitednumber of records have been found for bam-boo diseases in Africa and Central andSouth America. Within Asia there are severalcountries, for instances, the Philippines,Indonesia and Burma, for which little infor-mation is available. By comparison manyrecords exist for bamboo in the U.S.A.(Anon, 1960) which reflects more on theactivity of pathologists than on the impor:tance of either bamboo or bamboo diseasesSeveral Japanese works have been consultedon bamboo diseases: Kusano (1908) listsbamboo leaf rusts whilst Kawamura (1929)and Hino (1961) are more general. Bamboodiseases in India are usefully summarised byButler and Bisby (1960) and Bakshi (1976).These consider inter alia two very importantand widespread bamboo host genera,Bambusa and Dendrocalamus. Japaneseworkers have been largely concerned withSasa and its allies, and to a lesser extent Phyl-lostachys. Spaulding (1961) records many ofthe bamboo diseases. It is unfortunate, giventhe lack of data on symptoms and diseaselosses, that the original sources for the datawhich is presented are not given. This lack ofinformation on bamboo diseases has, how-ever, been a constant problem in any attemptto compile a comprehensive list of bamboo

diseases. Even where I was able to consultoriginal papers only a limited amount of detailwas available.

Many of the original references to bamboodiseases are not available, often because ofdifficulties in obtaining journals. Several refer-ences were obtained from two annotatedbibliographies (Elbourn, 1 9 7 8 ; Ridout,1983), which together cover the Review ofPlant Pathology (RPP) from 1973-1982.Earlier issues of the RPP were also consulted.

Scope of Bamboo Disease List

Only fungal diseases are consideredThere are many records of deuteromycetea(Ellis, 1971, 1976; Sutton, 1980) on bamboobut most of these have no association with adisease.

I have treated many of the records ofhigher fungi (mainly polypores) producingrots on living bamboo with some circumspec-tion. Bagchee and Singh (1954), for instance,give many instances of decay fungi which Ihave considered to be of dubious significance,and which have been omitted from below inthe absence of data from another source.Those rot and decay fungal records that arelisted should be treated with some caution(eg. Fomes spp.) since it is not clear whichpart of the bamboo is attacked - rhizome orculm.

One bacterial disease of bamboo inTaiwan (Lo et al., 1966) has been included.However, viruses (Anon, 1977; Kitajima etal., 1977; Lin et al., 1977), mycoplasmas(Nayar and Ananthapadmanabha, 1977) andmistletoes have been excluded. Similarlydecays and rots of cut bamboos are not consi-dered. There is no suggestion that bambooviruses cause any damage to their hosts. Aseries of papers by Kwan Soo Kim (1979) andKwan Soo Kim and Ji-Yul Lee (1980) investi-

271

gated the soil-borne fungi of Phyllostachysreticulata forests in Korea. None of these fungiwere associated with any disease of bamboo.

Importance of Bamboo Diseases

The relative importance of the differentdiseases is difficult to assess because of thegeneral lack of information accompanyingeach disease record. Despite this the overallimpression is that many of the bamboodiseases are of only limited importance. Itbecame apparent when compiling the list thatthe higher fungi (e.g. polypores and ascomy-cetes) had been more frequently recorded(perhaps because of their distinct fruitingbodies) than the deuteromycetes. Thehyphomycetes in particular are much under-represented and this, I feel, represents a lackof investigation into bamboo micro-fungirather than an absence of pathogens in thisgroup. There is no suggestion that any of themany leaf spot fungi, leaf rusts and decaypathogens cause more than minor damage.Severe attacks by rust fungi on bamboo havebeen noted, but only infrequently and withonly localized damage. By comparison thediseases of growing or young culms are muchmore serious, with extensive damagereported for bamboo blight (on Bambusaspp.) in Bangladesh, (Boa, this volume) andblight on Phyllostachys in China.

Bamboo Blight in Bangladesh

This important new disease of growingculms of Bambusa spp. is not included in thelist of diseases below because we are stilluncertain about its etiology. Elsewhere inthese proceedings (Boa: Rahman) the sheathrot pathogen of rice Sarocladium oryzae, andAcremonium stricturn are both linked withbamboo blight, particularly the former, but aconnexion between a fungal and the diseasehas still not been adequately demonstrated.

Further Work Required

1. Many of the records of diseases arequite old. It is important that these be up-

272

dated, together with a more complete pictureof the disease; for example. a full descriptionof symptoms and losses due to the disease.

2. The present records for bamboodisease do not adequately consider the veryimportant although widely dispersed resourceof rural village bamboos.

3. The growing culm has received littleattention with regard to disease. Young,green, wet tissue is more likely to be damagedby pathogenic organisms, and to a greaterextent, than mature culms.

There are several cryptic references to thedeath of new shoots at a very early stage.Pathological studies of these dying culms arerequired to establish whether this apparentlywidespread phenomenon is due to a living ornon-living (e.g. soil conditions) agent.

4. The culm sheaths play a very impor-tant part in the development of new culms. Ifgreen culm sheaths and/or the not fullyexpanded internode below are damaged, forexample by insects, this has an apparentlydramatic effect on the proximal part of thegrowing culm. The effect certainly extendsmuch beyond the area damaged and suggeststhat culm sheaths and the internodes thatthey protect are particularly susceptible todamage. Again this is an area to be investi-gated more fully.One of the difficulties here isthat culm sheaths naturally have a very shortexistence (approximately four weeks forBambusa vulgaris in Bangladesh) and it canbe difficult to discern accurately the develop-ment of abnormal necroses.

Format of Bamboo DiseaseListing

Diseases are listed alphabetically by thefungal (bacterium in one instance) associatedwith the symptoms. I have briefly describedthe type of fungus (e.g. Aphyllophorales(polypores), ascomycete etc.) the name ofthe disease, countries and hosts in which itoccurs, are also given together with a list ofappropriate references. I have not listed textssuch as Bakshi (1976) and Browne (1968)unless these are the only references.

I have not listed authorities for either hostor pathogen; this detail was not always avail-able in the papers consulted.

List of Fungal Bamboo Diseases

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

Aciculosporium take WITCHESBROOM (Japan; Taiwan)A s c o m y c e t eon Phyl lostachys aurea; P. bambu-soides; P. lithophila; P. malcinoi; P.nigra; P.. nigra var henonis; P.pubescens.C. Chen (1970, 1971); Kao and Leu(1976); Lin et al. (1981); Nozu andYamamoto (1972) : Shinohara (1965) ;Spaulding (1961).

Amauroderma rugosus (sic) CULMDECAY (India)Aphyllophoraleson BambusaBanerjee and Ghosh (1942)

Armillaria mellea PATHOGEN? (Kenya)Agarioalesassociated with Arundinaria alpinaGibson (1960)

Asterinella hiugensis BLACK MILDEWON CULMS (Japan)A s c o m y c e t eon Phyllostachys bambusoidesSpaulding (1961)

Astrosphaeriellafuscomaculans SPECK-LED CULMS (Japan)A s c o m y c e t eon Phyllostachys nigraThis infection enhances the value of theculms!

Balladyna butleri BLACK LEAF SPOT(India)A s c o m y c e t eon Bambusa sp.Butler and Bisby (1960)

Calocline chusqueae LEAF LESIONS(Ecuador)Coelomyceteon ChusqueaSutton (1980)

Ceratosphaeria phyllostachydisSHOOT BLIGHT (China)Ascomyceteon Phyllostachydis edulis

Cladosporium graminum LEAFMOULD (U.S.A.)

(10)

(11)

(12)

(13)

(14)

(15)

(16)

(17)

Hyphomyceteon Phyllostachys aureaAnon (1960)

Clavaria spp. SHOOT ROT (Thailand)Basidiomyceteon Bambusa spp.Giatgong (1980)

Coccodiella arundinariae LEAF SPOT(China, Japan)Ascomyceteon Phyllostachys sp.Spaulding (1961)

Colletotrichum graminicola AN-THRACNOSE (U.S.A.)Coelomyceteon Arundinaria giganteaAnon (1960)

Colletotrichum hsienjenchang CULMBLIGHT/ROT (Japan)on Phyllostachys bambusoides; P. nigravar. henonsisSpaulding (1961)

Coniosporium bambusae SHOOTWILT (U.S.S.R.)Hyphomyceteon Phyllostachys spp.B e r a d z e (1972), (1973a), (1973b),(1974), (1975a), (1975b)

Corticium lcoleroga THREAD BLIGHT(LEAF AND CULM DAMAGE) (India)Aphyllophoraleson Dendrocalamus sp.Browne (1968)

Dasturella bambusina LEAF RUST(India)Uredinaleson Bambusa sp.According to Bakshi (1978) the originalspecimen when re-examined showedthe host to be Dendrocalamus strictus.He also noted that the telia of D. bam-busina and D. dioina were the same.Mundkur and Kheswalla (1943)

Dasturella diuina LEAF RUST (India;Vietnam; Pakistan; Japan)Uredinales

273

on Dendrocalamus sp.; D. strictus;Oxytenanthera abeysannae (fide Bakshi(1968); Ox. abyssinica (fide Thiruma-Iachar and Gopalankrishnan (1947)).Alternative hosts Randia and Xerom-phis (Angiosperms).Bakshi and Sujan Singh (1967);Spaulding ,(1961); Sujan Singh andBakshi (1964)

18) Dicellomyces gloeosporus LEAF SPOT(U.S.A.)Basidiomyceteon Arundinaria tectaAnon (1960)

(19) Diplodia bambusae TIP BLIGHT(U.S.A.)Coelomyceteon “other bamboo spp.”Anon (1960)

(20) Encoelia helvola CULM ROT(Indonesia)Ascomyceteon Bambusa spp.; Bambusa arundi-nacea; Gigantochloa apusOvereem (1926) ; Rifai (1983)

(2 1) Epichloe bambusae WITCHES BROOM(Indonesia)Ascomyceteon Bambusa vulgaris; Dendrocalamusasper; Gigantochloa apus; G. atter; G.verticilliataRifai (1983)

(22) Erwinia sinoclami BACTERIAL WILT(Taiwan)Bacteriumon “Taiwan giant bamboo”Loetal. (1966)

(23) Fomes lignosus WHITE ROOT ROT(Malaysia)Aphyllophoraleson Dendrocalamus giganteusBrowne (1968) ; Hilton (1961)

(24) Fusarium moniliforme BASAL CULMROT (China)Hyphomyceteon Phyllostachys pubescensJ. Chen (1982)

(25)

(26)

(27)

(28)

(29)

(30)

(31)

(32)

(33)

(34)

Fusarium solani CULM BROWN ROT(China)Hyp homyceteLan (1980)

Ganoderma lucidum ROOT ROT (India,Pakistan, PhilippinesAphyllophoraleson Bambusa sp. B. arundinaceaBakshi (1957); Banerjee and Ghosh(1942) ; Butler (1909) ; Spaulding (1961)

Helminthosporium s p . L E A F S P O T(U.S.A.)Hyphomyceteon “other bamboo spp.”Anon (1960)

Hughesinia chusqueae LEAF SPOT(C hile)Hyphomyceteon ChusqueaEllis (1976)

Hypoxy lon rubiginosum CANKER/WHITE POCKET ROT (India)Ascomyceteon BambusaBagchee and Singh (1954)

Hypoxylon fuscopurpureum CANKER(India)on BambusaBagchee and Singh (1954)

Irpex flavus SPONGY SAP ROT (India?Ghana? Pakistan)Aphyllophoraleson Bambusa sp.Browne (1968)

Leptothyrium cylindrium LEAF SPOT(U.S.A.)Coelomyceteon Arundinaria tectaAnon (1960)

Loculistroma bambusae WITCHESBROOM (China)Ascomyceteon PhyllostachysAnon (1911)

Meliola bambusicola BLACK MILDEW(India)

274

(35)

(36)

(37

(38)

(39)

(40)

(41

(42)

(43)

(44)

A s c o m y c e t eon Bambusa sp.Browne (1968); Butler and Bisby (1960)

Meliola tenuis BLACK MILDEW(U.S.A.)on Arundinaria gigantea; A. tectaAnon (1960)

Merulius similis CULM DECAY (India)Aphyllophoraleson Bambusa bambosBanerjee and Bakshi (1945); Banerjeeand Ghosh (1942) ; Banerjee andMukhopadhyay (1962)

Mycosphaerella sp. L E A F S P O T(U.S.A.)A s c o m y c e t eon Phyllostachys bambusoides; P. nigraAnon (1960)

Mycosphaerella arundinariae LEAFSPOT (U.S.A.)on Arundinaria tectaAnon (1960)

Myrangium bambusaePARASITE” (C hina)A s c o m y c e t e

‘SEVERE

on Phyllostachys pubescensTai (1931)

Papularia arundia (= Arthrinium state ofApiospora Hyphomycete montagneifide Ellis (1965)) on Bambusa sp. CULMSOOTY STRIPE? (India)Ellis (1971) makes no mention of thiscommon bamboo fungus as a pathogen.I have frequently observed Arthriniumfreely sporulating on dead culm andtwigs. Bagchee and Singh (1954);Thirumalachar and Pavgi (1950) Phyl-lachora spp _ LEAF SPOTSA s c o m y c e t eFive species recorded widely

Phyllachora arundinariae (U.S.A.)on Arundinaria tectaAnon (1960)

Phyllachora bambusaePhyllachora malabarensis (India)Phyllachora shiraianaon Bambusa spp. Noted as being of littleimportance.

Butler and Bisby (1960)

(45) Phyllachora chusqueae (U.S.A.)on “other bamboo spp.”Anon (1960)

(46) PolyporusAphyllophoraleson Dendrocalamus strictusCause of death noted as Polyporus, inconjunction with Poria and Rhizoctonia(see Sheikh et al. (1978)

(47) Polyporus durus DECAY (India)on BambusaBanerjee and Ghosh (1942)

(48) Polyporus friabilis DECAY (India)on BambusaBanerjee and Ghosh (1942)

(49) Poria rhizomorpha ROOT ROT (India,Bangladesh (given as Pakistan))on Melocanna bacciferaSpaulding (196 1)

(50) Puccinia spp. RUSTS (U.S.S.R.)Uredinaleson bamboo - no other informationavailable.Beradze (1972)

(5 1) Puccinia arundinariae LEAF RUST(U.S.A.)on Arundinaria giganteaAnon (1960)

(52) Puccinia gracilenta LEAF RUST (India)on Bambusa sp.Bakshi and Sujan Singh (1967); Butlerand Bisby (1960)

(53) Puccinia ignaua LEAF RUST (U.S.A.)(see also Uredo ignava)on Bambusa vulgarisAnon (1960)

(54) Puccinia kusanoi LEAF RUST (Japan,U.K.)on Arundinaria, Sasa, Semiarundinariafastuosa , Alternat ive host Deutzia(Angiosperm)Reid (1978); Reid (1984) ; Spaulding(1961)

(55) Puccinia Iongicornis LEAF RUST(China, Indochina, Japan, U.K.)Uredinales

275

on Arundinaria, Bambusa arundinacea,Phyllostachys, Sasa.Reid (1978) ; Spaulding (1961)

(56) Puccinia phyllostachydis LEAF RUST(India, China, Japan, U.S.A.)(Also as P. melanocephala)o n A r u n d i n a r i a suberecta; Phyllo-stachys aurea; P. bambusoides; P. nigravar henonsisBrowne (1968) says that P. phyllo-stachydis is the correct name for P.melanocephala a s g iven by, forexample, Butler and Bisby (1960).Other references: Anon (1960); Bakshiand Sujan Singh (1967); Spaudling(1961)

(57) Puccinia xanthosperma LEAF RUST(India)Uredinaleson Bambusa sp.

. Bakshi and Sujan Singh (1967); Butlerand Bisby (1960)

(58) Pyricularia sp. LEAF INFECTIONS(Japan)Hyphomyceteon Phyllostachys; P. oryzae; Semiarun-dinaria spp.; S. viridis; Shibateae;Tetragonocala mus.Itoi et al. (1978), (1979)

(59) Pyricularia grisea LEAF SPOTS(Pantropical)on BambusaEllis (1971)

(60) Rhizoctonia DEATH OF CULMS,’CLUMP (Pakistan)AgonomyceteSee note for Polyporus

(61) Scolecotrichum graminis ( = Scilecotri-chum gra minis)Hyphomycete BROWN STRIPE OFCULM (U.S.A.)on Arundinaria tectaAnon (1960)

(62) Sclerotium rolfsii CULM ROT (U.S.A.)Agonomyceteon Bambusa vulgarisAnon (1960)

( 6 3 ) Selenophoma donacis CULM SPOT(U:S.A.)

Coefomyceteson “other bamboo spp.”Anon (1960)

(64) Shiraia bambusicola CULM SHEATHPATHOGEN? (China)A s c o m y c e t eon Phyllostachys sp Tai (1932)

(65) Stereostratum corticioides LEAF ANDSTEM RUST (China, Japan, Pakistan)Uredinaleson Arundinaria. P. bambusoides, P.nigra var henonisSpaulding (196 1)

(66) Stereum percome DECAY (India)Aphyllophoraleson BambusaBanerjee and Ghosh (1942)

(67) Tomentella bambusina CULM WILT(Brazil)Aphyllophorales(Tomentella = Trechispora)on Bambusa vulgaris

(68) Trametes corrugata DECAY (India)Aphyllophoraleson BambusaBanerjee and Ghosh (1942)

(69) Tunicopsora bagchii LEAF RUST ANDTWIG DEATH/WITCHES BROOM(India)Uredinaleson Dendrocalamus strictusBakshi et al. (1972); Sujan Singh andPandey (1971)

(70) Uredo dendrocalami RUST (SriLanka.China)Uredinaleson Dendrocalamus. D. latiflorusSpalding (1961)

(71) Uredo ignava LEAF RUST (China.Cuba. Puerto Rico, Venezuela)(See P. ignava)on Bambusa arundrnacea. B vulgaris.Dendrocalamus sp.Spaulding ( 196 1)

(72) Ustilago shiraiana S H O O T D E A T H

276

WITCHES BROOM (China, Japan,Taiwan, U.S.A.)Ustilaginaleson Bambusa spp., Phyllostachys bam-busoides, P. nigraAnon (1960); Hori (1905); Pattersonand Charles (1916); Speulding (1961)

(73) VolutelIa tecticola LEAF SPOT (U.S.A.)Hyphomyceteon Arundinaria tectaAnon (1960)

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Bakshi, B.K. (1957). Fungal diseases of Khair(Acacia catechu. Willd.) and their preven-tion . Indian Forester 83 6 l-66.

Bakshi, B.K. (1976). Forest Pathology. Prin-ciples and practice in Forestry. pp. 400.Forest Research Institute, Dehra Dun,India.

Bakshi, B.K.; Reddy, M.A.R.; Puri, Y.N.;Sujan Singh (1972). Forest disease survey(Final technical report). Forest PathologyBranch, F.R.I., Dehra Dun 117pp.

Bakshi, B.K.; Sujan Singh (1967). Rusts onIndian Forest Trees. Indian ForestRecords (N .S.) Forest Pathology 2; 139-198.

Banerjee, S.N.; Bakshi, B.K. (1945). Studieson the biology of wood rotting fungi ofBengal. Journal of Indian BotanicalSociety 24; 73-92.

Banerjee, S.; Ghosh, T. (1942). Preliminaryreport on the occurence of higher fungi onbamboos in and around Calcutta. Science&Culture 8; (4) 194.

Banerjee, S., Mukhopadhyay, S. (1962) Astudy of Meruliussimilis B. and Br. andassociated bamboo rot. Osttereich Bota-nische Zeitschrift 109; (3) 197212.

Beradte, L.A. (1972). Diseases of bamboo inSoviet Georgia. Subtropicheskie Kul’tury4; 132- 137.

Beradze, L.A. (1973a). Morphological fea-tures and pathogenicity of Coniosporiumbambuseae, the pathogen of a wilt ofbamboo shoots. Subtropicheskie Kul’turyNo. 3 171-173.

Beradze, L.A. (1973b). Study of the nutrionalphysiology of the fungus Coniosporiumbambuseae. Subtropicheskie Kul’tury No.6 151-154.

Beradze, L.A. (1974). The effect of variousfactors on the pathogen of wilt of bambooshoots Coniosporium bambuseae. Sub-tropicheske Kul’tury No. 1; 74-75.

Beradze, L.A. (1975a). Measures for the con-trol of bamboo seedling wilt. Subtro-picheskie Kul’tury No. 1; 99-102.

Beradze, L .A. (1975b), Toxic properties ofof the culture filtrate of the fungus Conio-sporium bambuseae. SubtropicheskieKul’tury No. 2; 144-145.

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Butler, E.J. and Bisby G.R. (1960). The fungiof India (revised by R.S. Vasudeva.) .Indian Council of Agricultural Research,New Dehli, India.

Chen, C. C. (1970). Witches broom - anew disease of bamboo in Taiwan.Memoirs College Agriculture, NationalTaiwan University 11; (2); 101-112.

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ltoi, S.. Sato, F., Yamamoto, J., Uchita. T.,Noda. C. (1979). Overwintering of Pyri-cularia on the living bamboo and bamboograss leaves and pathogenicity of the riceblast fungus, P. oryzae Cavara. to bam-boo and bamboo grass. Annals of thePhytopathological Society of Japan 45;375-385.

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279

The Occurrence and Bamboo Blight inBangladesh with Reference to

Sarocladium oryzaeEric R. Boa

Forest Research Institute, PO. Box 273,Chittagong, Bangladesh

Abstract

The symptoms of a blight of Bambusaspp. are described fully for the first time. Thedisease has only been recorded from Bang-ladesh and has been present since the early1970s. Bamboo blight attacks village bam-boos; in particular B. balcooa a n d B.vulgaris, the two most important species; theforest bamboos, dominated by Melocannabaccifera, are not affected. Details are givenof the losses in bamboo clumps resulting fromblight attack. Isolations from blight symptomshave consistently yielded Sarocladiumoryzae, the sheath rot pathogen of rice.Limited artificial inoculations with this funguson bamboo have resulted in symptoms similarto blight, but much more work is requiredbefore the cause of bamboo blight is fullyunderstood. There is much insect damage inblighted culms and observations suggest thatthese insect(s) are responsible for introducingS. oryzae into Ihe culm via feeding holes.

Introduction

There are few serious diseases ofbamboo. It was therefore with some alarmthat a brief note by Rahman and Zethner(197 1) recorded a damaging new disease,which they called bamboo blight, from villagebamboo groves of the Rajshahi district ofBangladesh. Subsequently little informationwas available on the disease, although there isno doubt that it continued to be a majorsource of worry to local farmers. Since 1982 acomprehensive research programme h a sbeen carried out by myself and Dr M A

280

Rahman of the Forest Research Institute,Chittagong. A colour brochure which de-scribes the disease in outline has been pro-duced (Boa and Rahman, 1984); the presentpaper provides a more complete descriptionof blight symptoms and reports the results ofisolations of fungi from diseased and healthytissues together with a discussion on the causeof the disease.

The chronology of research on bambooblight is as follows: 1971 - Disease firstrecorded in a brief note by Rahman andZethner (1971); 1975 Gibson (1975)during a brief visit to Bangladesh reported thedisease from additional areas; 1978 -Rahman (1978) described the results ofisolations from blighted bamboo; and 1982 -Bamboo blight project commences with thehelp of the British Technical CooperationProgramme.

Bamboo Species in Bangladeshand those which becomeBlighted

Bamboos in Bangladesh can be dividedinto two groups: the forest bamboos and thevillage bamboos. The latter are dominated byBambusa balcooa (Fig. la), and are generallythick-walled and form compact clumps withlarge culms 15-20 m. The former aredominated by Melocanna baccifera (Fig. lb)and are thin-walled with small ‘culms up toabout 10 m and both the species have pachy-morph rhizome systems. The village bamboosare found throughout the flat. deltaic regionsof Bangladesh and the forest bamboos in theupland regions (Chittagong Hill Tracts and

Fig. lb. Forest bmboo - Melocanna baccifera.

281

Sylhet region) although it is not uncommon tofind M. baccifera growing in villages.

Table 1 shows the iwo most affectedspecies are B. balcooa a n d B. vulgaris.“Jawa” bamboo is known only by itsname: on the basis of general appearanceand fringed auricles on its culm sheaths. Itwould appear to be a Bambusa ssensu lato (see Boa and Rahman,description) refers to a group of bamboos thatare difficult to separate on the basis ofvegetative characteristics and also show thesame type of blight development. The group-ing of these bamboo types into B. tulda s.1. ismade here for practical purposes only and isnot meant to have any taxonomic validity,Alam (1982). who provides a recent descrip-tion of bamboo species in Bangladesh,separates B. tulda s,I. into three separatespecies. The species described by Alam whichoccur in villages, and are not mentioned inTable 1, are of little importance and nonehave been seen blighted, This includesDendrocalamus giganteus Nunro, for exam-ple.

Bamboo blight has only been recordedfrom Bangladesh. Enquiries by the ForestResearch Institute of India to State ForestryDepartments yielded no records of blight

Table 1. Important bamboo species occurring inBangladesh villages and the presence of blight.

Species Notes ond i s t r i bu t i on

Over811 Degree ofseverity of disease

f i e l d development inattaCk single clumps

Bambusa balcooaRoxburgh

B. glaucescens (Willd .)Sieb. ex Munro

B. polymorpha Munro

’B . tulda sensu lato (seetext)

B. vulgaris Schrader exWendland

“JAWA” (local name -Bambusa sp .?)

Cephalostachyumpergracile Munro

Melocanna baccifera(Roxburgh) Munro

Widespread and abundantexcept for SE

Locally common in NE

Sporadic in NE and SE,perhaps elsewhere

Widespread though + oftenlocally sparse except in N

Dominant in SE but sporadicelsewhere

Common in W generally -absent elsewhere?

Apparently present in N only

Generally E of Jamuna river,widespread though patchy andsparse

+ +”

N O N E

NONE

+

+ + +

+ +

NONE

NONE

1 - 4b

NONE

NONE

1 -2

3-4

2-3

NONE

NONE

‘+ low,+ + + highbl (Minor) 25% new culms blighted; 2 (Mild) 25-50%;3 (Moderate) SO-75%; 4 (Severe) 75%

(Sujan Singh, pers. comm.). Of the specieslisted in Table ‘I which develop blight, B.

vulgaris is the only one of widespread impor-tance. Gamble (1896) states that B. balcooaoccurs only in Assam and what is nowBangladesh . B. vulgaris, however, occurs ex-tensively throughout Asia from India toMalaysia (Holttum, 1958), Indonesia andelsewhere. B. tulda s.1. is grown mainly in theIndian subcontinent (Gamble, 1896).

Symptoms of Bamboo Blight

Bamboo blight is easily recognized in thefield. in its later stages, by the presence oftruncated culms which show varying degreesof die back (Fig. 2a). Below this dead portionpartial necrosis (“streaking” - Fig. 3) isusually present. Streaking may extend direct-ly from the dead part of the culm or mayoccur lower down as discrete areas (Fig. 6a).Blight only attacks growing cuims and is thus

best observed from about July throughNovember. If a culm is still healthy after com-plete expansion has taken place, it will remainso. Culms are attacked at various stages ofdevelopment, in some cases when they havealready grown to 8 m or more, but observa-tions of the first stages of disease develop-ment have been made on culms whichbecame blighted when 1-4 m tall. Once aculm shows even slight development of blightsymptoms - at which stage no die back orstreaking is present - then it ceases growth.

Symptoms develop initially on internodeswhich are still growing and which areapproximately 40-60 cm below (Fig. 4a - farleft culm) the culm apex. At this stage ofdensely compacted internodes above -showno signs of symptoms either on the surface orinternally although subsequently these willdevelop and the apex will die.- These initialsymptoms on growing internodes cannotbe deteced by external examination of theculm since the supporting culm sheaths are

282

2

Fig 2b Die back ends at node

B

Fig. 3. Streaking of blighted culm. Three zones can beseen: A Orange/yellow discoloration, little or no stainbelow; B. Black/brown, stain below and usually insectchannels; C. Culm wall dead, light brown, “dried out”,often with fissures and long irregular cavities.

still in place, but their presence is indicated bya premature death of these culm sheaths.Removal of the culm sheaths reveals darkstained areas, almost always associated withinsect holes and channels (Fig. 4b). The blackstaining extends above and beIow the insecthole, with reduced lateral spread, and oftento the depth of the inner culm wall. Blackstained areas eventually become necrotic. Ifnecrosis develops sufficiently then die backwill occur (Fig. 2b) otherwise the production

of defence barriers (Fig. 5a) will restrict spreadand result in streaks (Fig. 3).

Insects are obviously of great importanceinspreading blight symptoms within the culmand also in introducing the disease. In severalculms insects had eaten through a healthyculm sheath and burrowed into the under-lying expanding culm tissue, where blackstaining was seen around the edge of the in-sect channels. In other cases the spread ofsymptoms was clearly linked with the burrow-ing of insects, for example as seen in olderblighted culms (4-8 months) (Fig. 5). It is notclear whether the same insects are responsiblefor burrowing both into tender culm tissueand older harder tissue, and causing theblight. So far no attempts have been made toidentify insect larvae found in culm walls. Thedevelopment of blight in affected species isdifferent, as shown in Fig. 6; for exampleculms of B. vulgaris are attacked at a muchearlier stage of growth whilst culms of B tuldas.1. tend not to show any streaking.

A feature of blighted bamboo in Bangla-desh is the failure of new culms to growbeyond a height of about 40 cm (Fig. 7b). Atthis stage internodes are densley compactedand only a premature death of the culmsheaths indicates that the culm is dying.When these dying young culms are split open(Fig. 7c) the origin of the disease can be seenat the base. The apex is still symptomless atthis stage and the basal rhizome regionhealthy.

There are also reports of dying youngculms from other countries where blight hasnot been observed. I have witnessed thisphenomenon o n Gigantochloa i n t h eBotanical Gardens, Bogor, Indonesia; Ueda(1960) carried out an extensive investigationinto dying young culms on Pbyllostachys spp.in Japan and Iisiung (pers. comm.) has fre quently noticed this occurrence on Phyllo-stachys in China. It appears unlikely thatdying young culms are part of the bambooblight disease syndrome in Bangladeshalthough this topic needs more careful anddetailed study to identify the cause of death.

Distribution of Bamboo Blightwithin Bangladesh

Bamboo blight has been seen throughout

284

285

4b

Bangladesh except the north-west (Fig. 8).The other main areas in which bamboo blightis absent are forest bamboos e.g. the east ofChittagong or village bamboos in areas nearBarisal where blight occurs in relatively lownumbers, The worst affected areas observedhave been: 1) Dhaka and surrounding dis-tricts, particularly towards Comilla; 2) Pabnaregion (east of Rajshahi) and 3) Chittagongand surrounding areas. Outside of these three

Fig. 5. Insect channels associated with internal staining: A) Oblique cross-section of 7 month-old culm. No externalsymptoms. (a) insect channels, (b) internal stain, (c) defence barrier restricts spread,* B) Longitudinal section through

internode immediately below the extent of die back.

--- Edge ofdie back

Insectchannels

Darkstaining

287

6b

Growth

Fig. ‘6. Blight development in about 7 month-old culms: a) Bambusa balcooa, streaking on 8 m culm, die back(not shown) of above internodes. Note discrete areas of streaking (arrows); b) B. vulgaris, culms attacked at earlystage of growth; c) 8. tulda s.1.

1 levelapproximately

Fig. 7. New culms at early stage of development: a) New culm and mother culm from which it arises. The newculm is completely ensheathed at this stage; b) Dead new shoot of Bambusa tulda s.l. as seen in January;

c) Dying new culm. f?. balcooa, wet stain in basal portion only, immature culm sheaths healthy.

288

7b

amboo blightbetween Clumps

Prior to 1982 there was little informationavailable on either the extent of the disease orits severity in different regions. Initially blightwas reported only from Rajshahi (Rahmanand Zethner, 1971). Four years later Gibson(1975) recorded blight from Sylhet, in thenorth east (Fig. 8), as well as Khulna andJessore. From 19 2 to 1985 I have regularlyvisited different regions, in particular several

small selected areas where healthy andblighted clumps have been kept under closeobservation, and there has been no evidenceto indicate that blight is a fast spreadingdisease. In three cases only (all B vulgarishave healthy clumps adjacent to blightedclumps, become diseased It is thereforeunlikely that bamboo blight first occurred onlyin the Rajshahi district: blight more probablyarose in several different regions around thesame time. It i s difficult to envisage blightspreading from Rajshahi hundred miles to

289

Sylhet in the space of four years. In 1985blight was readily seen between Rajshahiand Nawabganj but there was every indicationthat the incidence had decreased, A high inci-dence of blight. was seen in Dhaka and otherregions since 1982. This suggests that therehas been wide spread of the disease but it alsodemonstrates that the status of blight is notstatic and may even be on the decrease.

Lasses in Bamboo clumps due toBlight

Selected clumps of healthy and blightedbamboo from Chittagong, Sylhet andRajshahi were marked for all the new culmsthat appeared in 1983. and these new culmsmonitored monthly throughout the growingseason. Final assessments were then made

and culms divided into three classes: 1)healthy; 2) blighted; 3) dead yong culms (Fig.7b). Observations were made mainly ofblighted clumps of B. vulgaris and B, balcooa,Results show (Fig, 9) that more new culms inthe B. vulgaris sample became blighted,although other observations have shownsimilar levels of disease in some clumps ofblighted N. balcooa, Culms of B, vulgar i sbecome blighted at an earlier stage in theirgrowth, and subsequently blight symptomsextend further down the culm (Fig. 10). InB,balcooa there is a tendency for new culms tobecome blighted after expanding to 8 m ormore (Fig. 2a); in B. vulgaris culms are at-tacked at a much earlier stage (Fig. 6c), theconsequence of which is that more culms arecompletely killed (Fig. 10). This is an unusualevent in blighted clumps of B. balcooa. Inboth species the progress of die back is limited(Fig. 2b) and only occurs during or soon afterthe growing season has finished. There is

290

B a m b u s a vulgaris - b l i g h t e d c l u m p s

9a

1 2 3 4 5 6 7 8 9

Clump

H e a l t h y

Dead new culms

B l i g h t e d

Fig. 9. The fate of new culms produced by healthy and blighted bamboo clumps in 1983: A) Bambusa vulgarisblighted clumps: B) B. balcooa blighted clumps; C) B. balcooa and B. vulgaris healthy clumps.

then no further development of blight symp-toms although in following years newbranches which develop (on the blighted culm)healthy portion may die back. A major sourceof loss in both healthy and blighted clumps isthe failure of very young culms to develop(Fig. 9). This may be up to 60% of the newshoots in the case of blighted clumps of B.vulgaris. There was little difference in lossesdue to dead young culms in healthy andblighted clumps of B. balcooa. Ueda (1960)reported similar levels in healthy clumps ofPhyllostachys spp in Japan. it is not clearwhether the phenomenon of young culmsfailing to develop beyond a minimal height istherefore part of the bamboo blight diseasesyndrome.

What is the cumulative effect of blight onclumps over a period of years? Several of theclumps of B. vulgaris in Fig. 9 have died ineither 1984 or 1985. Others will die in 1986.In all these clumps blight has been the main

factor in their decline although the situationhas been exacerbated by bad planning andover-cutting. In B. balcooa there is no directindication that blight can kill clumps. Oftenthe proportion of new shoots that becomeblighted in successive years remains more orless constant and the fact that culms grow to amuch greater height before becoming blightedmust contribute to the lessened effect ofdisease on the health of the clump. So faronly anecdotal evidence and some indirectevidence (Fig. 11) exist to suggest that blightresults in the death of some clumps of B.balcooa (Fig. 12)

Isolation of Fungi from blightedand healthy Bamboos

Pieces of culm tissue were taken from theedge of blight symptoms and healthy culmtissue and placed on tap water agar (TWA)

292

8. balcooa - blighted clumps

1 2 3 4 5 6 7

Clump

9b

Healthy clumps

B. balcooa B. vulgaris

6 1

9 c Clump

293

40 30

s: PIC

o

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Bam

bu

sa

Ex

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d

ie

ba

ck

a

s a

pro

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rtio

n

of

hei

gh

t

b

alc

oo

a

30

20 10 0

Ext

ent

of

die

back

as

a

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pag

atio

n

of

hei

gh

t

He

igh

t o

fO

-1 m

l-4

m

4-8

m

bli

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ted

O

-l m

l-4

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10

Fina

l ex

tent

of

b

ack

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o

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ight

ed c

lum

ps:

A)

Bam

busa

(9 c

lum

ps);

B)

ba

lcoo

a(7

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mps

)

Fig, 11. Bambusa balcooa rhizomes dug up from clumps reportedly killed by blight in the Faridpur district; to beused for fuel in brick making,

(1.5% w/v) and incubated at 30°C, TWA that were only a week old to 2-3 months (Fig.restricted the growth of the faster growing 4). The recovery of S. oryzae from blightsaprobic fungi which were commonly symptoms on such culms was much higherisolated, including Coniothyriurn fuckelii (Table 3). Table 4 gives details of the tissuesSacc., Fusarium spp. and Pteroconium and sampled from blighted and healthy clumpsArthrinium anamorphs of A. piospora spp. and the resul ts of S, oryzae recovery.

lsolations from older blight symptoms: S. oryzae sporulates freely on TWA and can be

The first set of isolations were made from easily seen ( x 50) under a dissecting micro-

bl ight symptoms on 4 -8 month-o ld cu lms scope, even when other faster growing fungi

(Figs. 3 and 6). The fungus which aroused in- are present. Conidiophores tend to be simple

terest was the hyphomycete S arocladium and unbranched on the original isolation

oryzae (Sawada) W. Gams and D. Hawks. plate, the typical branched aerial con-

(Bady, 1980). the sheath rot pathogen on idiophores (Brady, 1980) best being seen on

r ice (Shahjahan et al,, 1977), and was potato carrot agar subcultures,

isolated from several clumps. S. oryzae wasobtained from 68 out of all clumps of blighted I n b o t h f3, balcooa a n d B . vulgaris, S,bamboo (Table 2). In several of these clumps oryzae was almost always isolated from the

die back symptoms only were present and if a black staining surrounding insect holes (Fig.separate sample is taken from these clumps of 4). The range of fungi found in early and late

13 clumps of B , vudgaris and 15 clumps of infections stages was similar. How

B . balcooa. all of which showed internal stain- fungus. tentatively identified as Periconia sp.,

ing and insect channels in addition to die back, was often isolated from young symptoms and

then the recovery of S. oryzae increases to was also seen to freely sporulate on the outer

100% and 85% respectively. surface of dying culm sheaths both on blighted

Isolations from young blight symptoms:and healthy culms. In some cases only bacteria

In a follow-up series of isolations tissues withdeveloped from young symptoms, particulwith samples from water soaked areas,

early symptoms were sampled. from culms

295

296

Table 2. Isolation of Sarocludium oryzae from older blight symptoms(Figs. 2b, 3, 5) on 4-8 month-old culms

Isolation ofSpecies Number of Sarocladium

blightedclumps

oryzae

sampled ! Y e s No

Bambusa balcooa 51 30 (59%) 2 1

B. tulda s.1. 1 5 10 (68%) 5

B. vulgaris 40 25 (63%) 15

“JAWA” (local 5name - Bambusa sp.?)

3 (60%) 25 3 (60%) 2

TOTAL: 1 1 6 71(61%) 45 (39%)

‘One or two culms per clump were sampled.

Table 3. Isolation of Sarocbdium oryzae from young blight symptoms (Fig. 4) on O-3 month-oldculms and from O-3 month-old culms in healthy clumps

Species State Number Isolation of

of of Sarocladiumclump clumps ! oryzae

Yes N o

B a m b u s a ba lcooa Healthy !" ’ 9 8 (89%) 1

Blighted 1 8 15 (83%) 3

B . vulgaris Healthy !" ! 1 0 6 (60%) 4

Blighted 1 3 11 (85%) 2

! One or two culms per clump were sampled. ! No die back or streaking was seen on any of the culms but insect holes and staining could be found in a few places

only.

freely sporulate on the outer surface of dyingculm sheaths both on blighted and healthyculms. In some cases only bacteria developedfrom young symptoms, particularly withsamples from water soaked areas.

Where S. oryzae only grew f r o m asample it was described as “pure”, and“mixed” when other fungi were present (asseen x 50 on TWA). About half the samplesfrom black staining at insect holes were“pure”; even where “mixed” the growth of S.oryzae was still marked. “Pure” S. oryzae wasalso obtained from symptomless parts of theculm (Table 4) in blighted clumps. Theseparts included the compacted area of culmsheaths inside the growing culm apex andbelow this from the edge of the uppermost

culm lumens (Fig. 7a). S. oryzae was alsoisolated from one apex of a completelyhealthy new culm in a blighted clump of B.balcooa and B. vulgaris.

Isolations from culm sheaths: Thepresence of S. oryzae on culm sheaths ofhealthy and blighted clumps was investigated.Both B. vulgaris and B. balcooa have hairyculm sheaths (Fig. 12) and these hairs weresampled by placing a few directly onto TWA.Isolations were also attempted from surfacesterilised necrotic patches on the culm sheathitself. S. oryzae was isolated from these earlynecrotic patches on some of the culm sheathssampled (Table 4), but several other fungiwere always present as well, with only smallareas of S. oryzae developing on the TWA.

297

Table 4. Isolation of Saroclaodium oryzae from O-3 month-old culmsin blighted snd healthy clumps according to type of sample.

Isolation of Sarocladium oryzae

Origin of sample Bambusa balcooa B. vulgaris

No. ofclumps Yes No No. of

clumps Yes No

a) Bl ighted Clumps

1. Black s ta in ing around insec t ho les(Fig. 4)

2) Black s ta in ing ex tending in toculm wal l wi thout insec t damage(Fig. 4)

3. Surface discolorat ion of culm(Fig. 4a)

4 . Dying young culms (Fig . 7)

5. Culm sheath necroses (Fig. 12)

6. Insect larvae from 1

7. T i s sue showing no s ign o fsymptom development(see text and Fig. 7a)

b) Healthy Clumps

1. Black s ta in ing a round i so la tedinsect holes occurr ing on a fewculms only

4. Dying young culms

5. Culm sheath necroses

14

Not seen

3

The amount of growth varied from smallareas 1-2 mm in diameter to other instancesin which it sporulated up to 15 mm away fromthe hairs. In a study of healthy bamboosgrowing in the north west, where no blight ispresent, S. oryzue was recovered from nineout of ten clumps of B. balcooa and three outof four dumps of B. tulda s.1. Isdations fromassociated healthy culm tissue were not at-tempted.

Acremonium strictum on bamboo:Rahman and Khisa (1983) reported the isola-tion of Acremonium stricturn from blightedbamboos, isolates of which were used inartificial inoculation experiments. Theseisolates have recently been re-examined atthe Commonwealth Mycological Institute andshown to be S. oryzae. The two fungi are infact very similar as shown by the descriptionsgiven in Holliday (1980).

13 1 9 8

1 6 4

1 1 0

0 5 2

Comments on the causes ofBamboo Blights

1

1

8

Only limited artificial inoculations havebeen carried out with S. oryzae on bamboo,both by Rahman and Khisa (1983) and my-self. Rahman and Khisa showed that S.oryzae (A. strictum as mistakenly reported -see above) produced a necrosis and resultedin the death of young branches, whichshowed a pattern of symptom deveIopmentsimilar to that seen in the field. I inoculatedfully extended internodes of 5 month-oldculms by wounding and which in turndeveloped a black staining spreading aboveand below the wound. No die back occurredor streaking. S. oryzae was re-isolated fromthese symptoms, It is only recently that it hasbeen shown that the first symptoms of bam-boo blight occur on growing internodes and

298

future artificial inoculations will concentrateon introducing S. oryzae to culm tissue at asimilar stage. Cross inoculations are alsoplanned with bamboo isolates of S. oyzue onriee and with rice isolates on bamboo to seewhether we are dealing with exactly the samefungus or whether a separate pathogenic racehas developed on bamboo. It is interesting tonote that sheath rot of rice was first reportedfrom Bangladesh at the same time as bambooblight (early 1970s). S. oyzae is seedborne inrice (Shahjahan et al., 1977) and it issuggested that this is how the fungus was in-troduced to Bangladesh (Dr S Miah, Bangla-desh Rice Research Institute, pers. comm.).The fungus is now found throughout Bang-ladesh on both diseased rice and blightedbamboo and even on the culm sheath hairs ofhealthy bamboos in blight-free areas. The ex-tent to which S. oryzae is present on culmsheaths of healthy clumps in blighted areashas still to be examined.

How important is BambooBlight?

Bamboo blight must be considered aserious disease if only because it attacks thegrowing cuim, stops any further growth andproduces a die back which may in some casekill the cuim completely. Even if this onlyhappens in a few cuims of a season’s growththis could represent a major loss to thefarmer. The importance of the disease inclumps of B. balcooa varies; some clumpsmay show one or two clumps which developblight each growing season whilst in otherclumps most of the new cuims becomeblighted. The effect of the disease on B.vulgaris is more serious, and blight can killclumps, especially when the already signifi-cant effects of blight are compounded by over-cutting and badly planned cutting. Althoughthe disease is not causing widespread damagethroughout Bangladesh, as was feared mighthappen, it is a major problem in several areas.Concern about the disease should not,therefore, be allowed to wane. Blight mayhave decreased in some areas but it hasbecome more of a problem in others. Thedisease is at present only found in Bangladeshbut S. oryzae is a widespread pathogen onrice and occurs throughout Asia along withvarious Bombusa spp. Priori ty areas ofresearch must be to fully examine the patho-genicity of S. oryzae on bamboo and also in-vestigate the role of insects both in introduc-

ing the fungus into the culm and facilitatingthe spread throughout the cuim (and betweenclumps).

ReferencesAlam, M.K. 1982. A guide to 18 species of

bamboo from Bangladesh. Bulletin 2,Plant Taxonomy Series. Forest ResearchInstitute, Chittagong , Bangladesh.

Boa, E.R. and Rahman, M.A. 1984. Bam-boo blight in Bangladesh. OverseasDevelopment Administration, LondonUK. (Available at address of seniorauthor.)

Brady, B.L.K. 1980. Sarocladium oryzae.Commonwealth Mycological InstituteDescriptions of Plant Pathogenic Fungiand Bacteria. No. 674. CommonwealthMycological Institute, Ferry Lane, Kew,Surrey, UK.

Gamble, J.S. 1896. The Bambuseae ofBritish Inida. 7. Annals of the RoyalBotanic Garden, Calcutta.

Gibson, I.A.S. 1975. Report on a visit to thePeople’s Republic of Bangladesh. Over-seas Development Administration,London.

Hoiiiday , P. 1980. Fungus diseases oftropical crops. Cambridge UniversityPress, London,

Hoittum, R.E. 1958. The bamboos of theMalay Peninsula. Garden’s Bulletin,Singapore 16: l- 135.

Rahman, M.A. 1978. Isolation of fungifrom blight affected bamboos in Bangla-desh. Bano Biggyan Patrika 7: 42-49.

Rahman, M.A. and Khisa, S.K. 1983. Bam-boo blight with particular reference toAcremonitium strictum. Bane BiggyanPatrika 10: l-13 (Issued 1985).

Rahman, M.A. and Zethner, 0. 1971. Aninterim report on results obtained inF o r e s t P a t h o l o g y S e c t i o n f r o mSeptember 1969 - August 1971. ForestDale News 4: 46-48.

Shahjahan, A.K.M., Harahap, Z. and RushM.C. 1977. Sheath rot of rice caused byAcrocylindrium oryzae in Louisiana.

Plant Disease Reporter. 61: 307-310.

Ueda, K. 1960. Studies on physiology ofbamboo, with special reference to prac-tical application. Kyoto University ForestsBulletin. Number 30. Kyoto.

299

Utilisation

300

The Role of Bamboo as a PotentialFood Source in Thailand

Kamol VisuphakaRoyal Forest Department, Bangkok, Thailand

Abstract

This paper summarises the information onbamboo shoot production in Thailand, themain components and food value of bambooshoots, possible increase in production forthe next five years, and potential economicbenefits.

Introduction

Thailand’s total area is 513,115 km2. Thecountry is located in Southeast Asia,between the latitudes 5° and 21°N andthe longitudes 97° and 105°E. The humidtropical climate is influenced by seasonalmonsoon and the local topography. Theforest types are varied, with rich flora rangingfrom tropical evergreen forests on the Penin-sula to dry, deciduous, dipterocarp forestscattered in the northern, central and north-eastern parts of the country. The species ofbamboo in Thailand are abundant including12 genera and 41 species. Bamboos grownaturally as scattered undergrowth in all foresttypes throughout the country. There is onlyone area where bamboos are found as purestands, in Kanchanaburi province, about200 km west of Bangkok. In Thailand, bam-boos are used for a variety of purposes,including food, household construction, sup-

porting poles, pulping, basketry and otherhandicrafts.

The Sprouting of Bamboo

Bamboo shoots develop from rhizomesduring the rainy season. The buds on rhizome-nodes enlarge for several months in the soil.The shoots emerge out of the ground in theform of tender, pointed cones covered withimbricate sheaths inserted at the nodes. Theseshoots then elongate rapidly, and after o n emonth they will develop into mature woodyculms. The number and period of sprout-emergence out of the ground vary accordingto the species, the size and vigour of theclump, and also the environmental conditionof the locality. It varies from 50 to 60 daysbetween early and late-sprouting. The sprout-ing is strongly influenced by rain in May andJune. An investigation on bamboo sproutingwas carried out during the rainy season in1970 (Watanabe, 1972) with results shown inTable 1.

Nutritive Value of BambooShoot as Food

The young and tender shoots of most ofthe edible bamboo species are consumedfresh or made into pickles, vegetables and

Table 1. Period of bamboo sprouting.

Species Beginn ing E n d i n g Period (days)

Bambusa arundinacea May 10 J u n e 25 4 6

Bambusa vulgaris May 1 J u n e 22 5 2

B a m b u s a tulda May 25 J u n e 27 3 3

Thyrsostachys siamensis May 15 J u n e 1 4 7

3 0 1

May June

10

. . 5

Ju ly

Number of shoot sprouted

O-- - - - - - - - - -O Precipitation

Fig. 1. Relationship between the number of bamboo sprouts emerged out of the ground and the precipitation.

dried forms that are considered delicacies.

Quantities of shoots at three ages (7, 10and 15 days after emergence) have beenstudied (Tamolang et al., 1980). The nutrientcomponents such as protein, fat, ash, totalcarbohydrates, crude fiber, calcium, phos-phorus, iron, thiamine (Vitamin Bl) andascorbic acid (Vitamin C) were chemicallyanalysed. Results showed that age has norelationship to nutrient contents. The shootswere made up of more than 75% water.

The contents of nutrients in bamboo shootsvary according to the different parts of thebamboo sprout. The soft tissue, close to theapex, contains less coarse fibers and are pro-tein rich. The lower parts, especially the por-tion where the sheaths were peeled off, con-tain less protein and more coarse fibers.Results of a study of nutrient components ofPhyl lostachys edulis sprout were reported(Resources Bureau Reference Data No. 34,1960) and are given in Table 2:

Bamboo for Food ProductionYoung and tender bamboo shoots are

used as daily food for Thai people because ofits good taste and low cost. The shoots arehighly nutritious, palatable and can be cookedand prepared in many delicious ways. Mostbamboo sprouts consumed are harvested fromnatural forests. Only one species comes fromcommercial plantation of Dendrocalamusasper, which appears to top the list of ediblebamboo species. The edible species of bam-boo in Thailand commonly used for food areas follows:

1. Pai Tong - Dendrocalamus asper2. Pai Seesuk - Bambusa blumeana3. Pai Ruak - Tbyrsostachys siamensis4. Pai Ruakdam - Thyrsostachys oliverii5. Pai Bong - Dendrocalamus brandisii6. Pai Sangdoi - Dendrocalamus strictus7. Pai Rai - Gigantochloa albociliata

Besides local consumption, bambooshoots are also exported. (Table 3).

302

Table 2. Analytical results of bamboo sprouts (per 100 g fresh matter).

Nut r i en t Fresh matter Canned food

Crude prote in 2.5 g 1.9 g

Crude fat 0.2 g 0.1 g

Carbohydrates - Sugar 2.9 g 2.9 g- Crude fiber 1.0 g 1.8 g

Water content 92.5 % 92.8 %

Calorie. 23 cal. 20 ca l .

A s h 0.7 g 0.4 g

Lime 1 mg 1 mg

P h o s p h o r u s 43 m g 26 mg

Iron 7 m g 1 mg

Vitamin - A 50 i.u. 50 i.u.

- 0.10 m g 0.05 mg- 0.08 mg 0.05 mg- C 10 m g 0 mg

Table 3. The export of bamboo shoots of Thailand.

1 . Fresh , chi l ledbamboo shoots 288.8 222,821 338.9 382,062 238.5 165,873

2 . Dry Bamboo shoots 29.7 129,182 15.2 48,332 - -

3 . Canned bamboo 5,864 3,030,309 8,557 3,406,347 - -s h o o t s

Source: Department of Business Economics, Ministry of Commerce, Bangkok, Thailand.

It is difficult to obtain accurate informationon the real consumption of natural bambooshoots, since there is no restriction for collec-tion of bamboo shoots from forests. Theoriginal bamboo plantations are mainly inPrachin Buri Province, 120 km east ofBangkok, and others were subsequentlyestablished successfully in every part of thecountry. The agricultural areas converted toplantations of Dendrocalamus asperare 6,000ha at present and expected to double to12.000 ha by 1991.

ReferencesTamolang, F.N., Lopez, F.R., Semana, J.A.,

Casin, F.R. and Espiloy, 1980. Propertiesand utilization of Philippines erect:bamboo. 180-200. In: Proceedings ofBamboo Workshop, Singapore.

Watanabe, M. 1972. Report of technical ser-vice and research work on silvicultureand management of bamboo forest inThailand Overseas Technical Coopera-tion Agency. Tokyo, Japan.

Resources Bureau Reference Data No. 34,1960. Studies on the physiology of bam-boo with reference to practical applica-tion. Tokyo, Japan.

303

The Changes in Nutrient Composition ofBamboo Shoots at Different Ages

Hu Chaozong

Zhejiang Forest College, Zhejiang, China

Abstract

The moisture content of bamboo shoots ofthree different ages increases gradually withage, and finally averages at about 92%. Therough fibers also increase with age, as thetissue grows old. ln contrast, the nutrient com-position such as protein, amino-acids, fat, car-bohydrate, other minerals. inorganic saltsetc., decrease with age. Therefore, the righttime to gather the spring bamboo shoots iswhen they are still underground. It will cer-tainly affect the quality of bamboo shoots if thegathering time is prolonged.

Introduction

Phyllostachys pubescens, a l s o c a l l e dMengzong Bamboo Shoots is China’sbamboo. They are cultivated extensively fortheir shoots. China’s output of these shoots isthe highest in the world. The quality of bam-boo shoots largely depends on the number ofdays after the sprouts’ appearance on theground which is also taken as the age of bam-boo shoots. Both qualitative and quantativeanalyses of the nutrient composition of bam-boo shoots are made to provide scientific basisfor the gathering time of quality shoots. Betterquality shoots fetch higher prices.

Samples and Methods

On ApriI 4, 1984, in the bamboo grovesof Wuxing Village, Miaoshan Township in thesuburbs of Ningbo, Zhejiang Province, 23bamboo shoots, the sheaths of whichappeared on the ground, with the sprouts stillunderground, were selected as samples foranalysis. On that day, five shoots weregathered and the others were marked, which

were subsequently gathered once every fivedays, seeing to it that they were almost of thesame size. At first collection, the averageshoot length was 19.53 cm and the peri-meter was 20.37 cm. On April 9, the secondcollection, the average length and perimeterwere 25.23 cm and 20.74 cm and duringthird collection the averages were 36.41 cmand 2 1.06 cm respectively.

The gathered shoots were transported tolaboratory in refrigerated flask. They werepeeled instantly and the unedible part was cutoff with a stainless steel knife. In order to doaway with individual differences as much aspossible, each shoot was first cut verticallyand then horizontally, forming small squares.These squares were thoroughly mixed and500 g was taken as samples. Of this, 20 g wasdried at 10°C in an oven for 20 minutes,fresh samples were used for analysis ofmoisture content. The other samples werethen dried at 80°C in a drier. The driedsamples were ground into powder and storedin bottles for further use.

Methods of analysis: 1. Protein wasdetermined by K’s nitroimetric analysis.2. Amino-acids were determined by Hitachi835-50 Model amino-acids auto-analysisinstrument. The qualitative and quantitativeanalyses were made of protein- hydrolysateamino-acids. 3. Fat was determined byresidues. 4. Sugar and soluble sugar weredetermined by colorimetric analysis.5. Fibers were determined by acid-alkalianalysis. 6. Ash content was analysed by dryash determination. 7. Phosphorus was deter-mined by anti-calorimetric analysis of Molyb-denum and antimony. 8. Calcium and ironwere determined by atom-absorption spectro-metric analysis. 9. Moisture content wasdetermined by drying at 105°C in an oven.lg of carbohydrate produces 4,000 calories;

3 0 4

1 g of fat produces 9,000 calories; 1 g of pro-tein produces 4,000 calories. 11. Vitamin Cwas substracted with 1% oxalic acid and deter-mined by titrimetry of 2.6

Except the data for amino-acids, the datafor other items are the averages of thethree analyses. In order to compare thepresent data with other vegetables, the dataare converted into percentage of freshbamboo shoot weight.

Analysis and Results

The changes of protein and amino-acids: The bamboo shoots of the threedifferent ages (one with sprouts underground,another with sprouts appearing on theground five days, and still another with

g/100 g

3

E 2

1

Fig. 1. The changes of protein in bamboo shoots of thethree different ages.(1) Sprouts underground.( 2 ) Sprouts appearing on the ground 5 days.( 3 ) Sprouts appearing on the ground 10 days

sprouts appearing on the ground ten days),have a high content of protein, higher thanany other varieties of vegetables. However,protein decreases with age; every five days,the protein is reduced by 11.7% to 3.7%(Fig, 1)

The bamboo shoots of the three differentages contain 18 varieties of protein hydro-lysate amino-acids. They are ASP, THR,SER, GLU, GLY, ALA, CYS, VAL, MET,ILE, IEU, TYR, PHE, LYS, NH3, HIS, ARG,PRO, etc. (See Fig. 2, a.. .r indicate thepeak amount of various amino-acids).

From part of the data shown in Fig. 2, wegot Chart I. The bamboo shoots of the threedifferent ages contain the highest amount ofTYR, almost accounting for 3.51% of theweight of the dried bamboo shoots, whichincreases with age. TYR amounts to 4.8% inthe bamboo shoots ten days after the sproutsappeared on the ground. That is unfavour-able for bamboo shoots processing and can-ning for it produces some white coaguia,greatly affecting the quality of boiled bambooshoots. Besides TYR, GLU and ASP are alsorich; their content decreases with age. Youngbamboo shoots of small size is deliciousbecause they are rich in GLU. The content ofPRO, IEU and ALA amounts to over 1%respectively, that of the former decreasingwith age while that of the latter, though vary-ing, a little, remaining almost stable.Nutrients contained in bamboo shoots areCYC and HIS, which are stable, too. Thetotal content of amino-acids decreases withthe age of bamboo shoots.

Fig. 2. The changes of amino acids in bamboo shoots of the three different ages

305

Table 1. The changes of amino acids in bamboo shoots of the three different ages(per 100 g dried matter).

Portionsprouts

undergroundSprouts appearing on the ground

5 days 10 days

ASP

THR

SERGLU

G L YALACYS

YAL

METILE

LEU

T Y R

PHE

LYSNH3

HIS

ARG

PRO

3.31474 2.42582 2.54518

0.72376 0.75652 0.70892

0.79628 0.79064 0.71882

3.22632 2.71544 2.7336

0.7221 0.77014 0.71612

1.12158 1.1923 1.05694

0.22232 0.20068 0.22068

0.947 1.0026 0.91458

0.3095 0.35472 0.29906

0.63158 0.70166 0.61968

1.13114 1.24632 1.10554

3.51496 4.8589 4.81126

0.70734 0.81078 0.73556

0.64868 0.68206 0.52818

0.69698 0.52746 0.7234

0.30132 0.32292 0.28432

0.89742 0.92424 0.79932

1.2212 0.7913 0.5865

Total. 21.13422 21.0745 20.10766

The changes of fat in bambooshoots of the three different ages:Though very little, fat is richest comparedwith the fat content of other varieties of vege-tables. Fat increases progressively with theage of bamboo shoots though the change isvery little (See Fig. 3).

8/100 g

Fig. 3. The changes of fat in bamboo shoots of thethree different ages.

The changes of carbohydrate inbamboo shoots of the three differentages: Carbohydrate in bamboo shootsinclude sugar, soluble sugar, rough fibers, etc.For the content of sugar, soluble sugar andrough fiber, see Fig. 4. With age, sugar andsoluble sugar increase by 13.3% to 17.0% infive days and by 26.6% to 32.2% in tendays. Five days after the sprouts’ appearanceon the ground, the rough fibers increase by14.6%, and ten days by 18.8%. The tissuegrows older and gradually becomes inedible.

The changes of moisture contentand quantity of heat in the bambooshoots of the three different ages: Theanalysis shows that moisture content in thebamboo shoots of the three different agesincreases with age (90.83% - 91.72% -92.05%) till it reaches a period of steadiness.In contrast, the quantity of heat decreases

306

g/ 100g

3 Sugar S o l u b l esugar

Crude fiber

Fig. 4. The changes of carbohydrate in bamboo shoots of the three different ages

progressively with age (23.56% 21.05%- 18.7 1%) . In terms of the structure of quan-tity of heat (energy) bamboo shoots are rela-tively rich with nutrients (Fig. 5).

The changes of inorganic salts inthe bamboo shoots of the three differentages: Bamboo shoots are rich in ash contentwith the average of 0.74 g in 100 g of fresh

92

9 1

21

20

19

samples. The changes in ash content are little(from 0.73% to 0.75%) with age. Phos-phorus and calcium decrease by 16.0% and37.5% respectively five days after thesprouts’ appearance on the ground, and by25% and 43.8% respectively ten days afterthe sprouts’ appearance on the ground. Ironsteadies between 0.29 mg to 0.44 mg (SeeFig. 6).

( q u a n t i t y of h e a t )

3Sugar

(quantity of heat)

F a t( q u a n t i t y of h e a t )

3 C a l o r i e s2

1

1 1

10

9

Fig. 5 The changes of moisture content and quantity of heat in the bamboo shoots of thethree different ages

307

Fig. 6. The changes

mg/100g

Ca

of inorganic salts in the bamboo shoots of the three different ages.

Vitamin C and other nutrient contentsare very little, accounting for about 0.001%in the iced bamboo shoots.

Conclusions

The above analyses show that bambooshoots are nourishing vegetables. With the ageof bamboo shoots after the sprouts’ appear-ance on the ground, moisture contentincreases slowly till it steadies at about92% Rough fibers increase with age, and asa result, the tissue grows old, and the bambooshoots become inedible. In contrast, protein,amino-acids, fat, carbohydrate, quantity ofheat and inorganic salts, etc., decrease vari-ably with the age of bamboo shoots. There-fore, in terms of nourishment, it is wrong toput off the gathering time of bamboo shoots,which results in higher output but of poorquality. In terms of processing, early gather-ing of bamboo shoots results in high qualitythough lower output. In particular, theincrease of white coagula greatly affects thequality of boiled bamboo shoots. Therefore, itis the right time to gather bamboo shootswhen they are still underground with sheathsjust appearing on the ground. Quali ty

deserves greater attention for bamboo shootswhich are to be eaten fresh or to be canned. Inrecent years, there appears a tendency in cer-tain places in the countryside to put off thegathering time for bamboo shoots. Thatraised the output a little, but greatly loweredthe quality of bamboo shoots. The edibleparts becoming less, suitable for canningand suitable only for drying.

The following three references give addi-tional information. "

1. T h e M e t h o d s o f D e t e r m i n g F o o dNutrients, 1961. Compiled by ChinaResearch Institute of Medical LabourHygiene, Protection and OccupationalDiseases, People’s Publishing House,Beijing.

2. Chemical Analysis of Food, 1979.Compiled by Shanghai CommoditiesExamination Bureau, Shanghai Scienceand Technology Publishing House,Beijing.

3. Li Shixuan, 1984. Physiology of Vege-tables Storage and the Techniques of AirConditioning. Shanghai Science andTechnology Publishing House, Beijing.

"! not cited in text.

308

Characterization of Steam-Exploded Bamboosfor ‘Cattle Feed

T. Higuchi, M. Tanahashi and Y. Togamura’

Wood Research institute, Kyoto University, Uji, Kyoto 61 1, Japan*Department of Animal Science, Faculty of Agriculture, Kyoto University,

Sakyo-ku, Kyoto 606, Japan

Abstract

By steam-explosion process bamboossuch as M o s o c h i k u (Phyllostachyspubescence) and Chishimazasa (Sasskur i l ens is ) were converted to easilyhydrolyzable materials (EXBs) by cellulase,and the EXBs were digested remarkably by theruminants. The different values were as fol-lows: Saccharification, 95% and 87% of cellu-lose of the respective EXBs, and in vitrodigestibility of the Mosochiku EXB, 50% ofdry matter (DM). These values are comparableto those of exploded wood (EXW) of whitebirch (Betula platiphilla and better thanthose of Japanese larch (Larix leptolepis)EXW. The results indicated that the utilizationof bamboos for cattle feed and fermentationare promising by the steam-explosion process.

Introduction

Wood including bamboo is by far the mostabundant biomass on earth, and it can be end-lessly renewed. The need to develop renew-able alternatives to petroleum, and to meet theworld’s growing requirements for fuel andfood are important. However, because ofchemical and structural heterogeneity thewood conversion process is still not econom-ically feasible. Wood is a composite materialcomposed of cellulose. hemicellulose andlignin, and that cellulose is embedded in amatrix of lignin-hemicellulose complexes.Papers on the conversion of wood to ruminantfeed are published (Jackson, 1977; Klopfen-stein, 1981). It is known that for enzymicsaccharification and digestion of wood byruminants, delignification or cleavage of thelignin-carbohydrate linkages is a prerequiste.

(Tsao et al., 1978). We have investigated thesteam-explosion of woods and bamboos toaccomplish economically feasible separationof cellulose, hemicelluloses and lignin ofwoody materials for chemicals, pulp andenzymic saccharification (Tanahashi, 1983;Tanahashi and Higuchi, 1983; 1985;Tanahashi et al., 1983). This paper reports onthe enzymic saccharification and ruminantdigestion of the steam-exploded bamboo(EXB).

Materials and Methods

Chemical analysis of bamboos: Theculms of Mosochiku (P hyllostachyspubescence) and Chishimazasa . (Sasakurilensis) were pulverized to 60-80 meshesand analyzed by a standard wood analysismethod.

Preparation of steam-exploded bam-boos (EXBs): Chips (500g. ca. 30 mm x 20mm x 15 mm) of Mosochiku and Chishima-zasa were treated with saturated steam at28kg/cm2, about 230°C for 1, 2.4.8 and 16mins. Then steam pressure was instanta-neously released to the atmospheric pressurevia a ball bulb to give the EXB. White birch(Betula platiphilla). Japanese larch (Laix

leptolepis) and rice straw were exploded at asimilar condition. For the enzymic saccharifi-cation and determination of in vitro digestibi-lity, wet EXB and EXW were freeze-dried andmilled by a Willey mill with 1 mm meshesfilter.

Saccharification of EXBs and EXWswith cellulase: Two hundred mg of freeze-dried EXBs. EXWs. and untreated bambooand wood powder (40 meshs pass 80 mesheson) were subjected to Trichoderma cellulase

3 0 9

(Meicelase 8000 units, kindly donated byMeiji Seika Co.) digestion in 10 ml of acetatebuffer (OIOZM, pH 5.0), at 4O°C for 48 hrs byusing a Monod-shaking incubator. Afterenzymic hydrolysis the sample was heated ina boiling water bath for 1 min and filtered.One ml of the filtrate was diluted to 100 mland the total reducing sugars or glucose wasdetermined according to Somogi-Nelsonmethod or by a glucose analyzer.

in vitro Digestibility of EXBs andEXWs: Freeze-dried EXBs, EXWs, untreatedbamboo and wood powder were analyzed fordry matter (DM), organic matter (OM), crudeprotein and fat by the standard method.Separately, EXBs and EXWs were treatedwith a pronase solution and separated toinsoluble cell wall structural fraction (CW) andsoluble fraction according to the Abe’smethod (Abe et al., 1979). In vitro digestibi-lity of EXBs and EXWs was measured bytreating the samples with a mixture solution ofthe stomach juice of a sheep and an artificialsaliva of McDougall at 38°C under stream for 48 hrs. After the treatment thesample was centrifuged and treated with thepronase. Then, DM, OM, and OCW weredetermined, and in vitro digestibility of therespective fractions was calculated(Togamura et al., 1983).

Results and Discussion

Chemical composition of bamboos usedin the present investigation is shown in Table1. Cellulose contents of both bamboos wereabout 50%. Fig. lA-D shows scanning elec-tron micrographs of the fibers of white birchEXW (Tanahashi et al., 1983). Vessels (a),fibers (b) and amorphous substances (c) areseen in Fig. 1A. Most of vessels weredestroyed to small fragments. Fibers sufferedfrom some damage as a buckling (Fig. IA-D),

a cleft along the fiber axis (Fig. 1B) rupture atthe middle of a fiber (Fig. lC), expansion in adome shape (Fig. 1D). The appearance ofEXBs was similar.

Mosochiku and Chishimazasa EXBs, andEXWs of white birch and Japanese larch weresubjected to enzymic hydrolysis using aTrichoderma cellulase (Meicelase). Theresults are shown in Figs. 2 and 3. Untreatedwood and bamboo powder gave less than 5%saccharification with the enzyme, whereasMosochiku EXB, Chishimazasa EXB andwhite birch EXW gave 59%, 44% and 68%saccharification, corresponding to 95%, 87 %and 98% of cellulose of the samples, respec-tively. However, Japanese larch EXW(28kg/cm2, 4 min) gave 37% saccharifica-tion. The poor saccharification of the larchEXW with the cellulase could be ascribed toanatomical differences of wood, higher Iignincontent, and structural differences of lignin.Coniferous woods are composed of mainlytracheids, and the lignin is composed mainlyof guaiacyl lignin which is more condensedthan guaiacylsyringyl lignin in hardwoods andgrasses. However, we recently found thatpretreatment of electron beam irradiation ofconifer wood chips or after ball milling ofconifer EXWs gave almost the same sacchari-fication as in hardwood EXWs (Tanahashiand Higuchi, Unpublished data). Hence, itwas indicated that EXBs and white birchEXW were suitable for enzymic saccharifica-tion and ruminant feed.

in vitro Digestibility of EXBs andEXWs: Bamboo, wood and rice straw con-tain large amounts of cellulose and hemicellu-lose but are low in values as ruminant feed,because of their low digestibility due tophysical and chemical linkages between poly-saccharides and lignin in the materials. How-ever, by steam-explosion these linkages werecleaved and these materials were converted

Table 1. Chemical composition of bamboos

Mosochiku

Chishimazasa

Solubility in

A s h Hot -wa te r 1% Alcoholbenzene Ce l lu lo se Pen tosan LigninNaOH

(%) (%) (%) (%) (8) (%) (%)

1.3 20.0 32.2 4.6 49.1 27.7 26.1

1.9 13.1 38.7 9.2 52.3 25.0 19.4

310

Fig 1 Photographs of white birch EXW (28 kg cm2,2 mm 1 (Scanning electron microscope

A, (a) vessels, (b) ftbers, (c) arnorphous substance.(d) buckling and (e) exponslon of a fiber

B, a cleft along a fiber

C. explosion of a fiber

D, expansron

311

80

20 0

01

24

81

6S

t

ea

mi

n

g

ti

me

(m

i n)

Fig

2S

acch

arifi

catio

n (%

) o

f ce

llulo

se o

f M

osoc

hiku

E

XB

0 :

ste

am

pres

sure

, 28

kg

/cm

2

:

ste

am p

ress

ure.

24

kg/c

m2

0 :

stea

m

pres

sure

. 20

kg

/cm

2un

expl

oded

ba

mbo

o po

wde

r

01

24

81

6

St

ea

mi

ng

ti

me(m

in)

Fig

. 3

Sa

ccha

rific

atio

n (%

)

of

cellu

lose

of

ex

plod

ed

mat

eria

ls

o :

Chi

shim

azas

o (s

team

pr

essu

re,

28

kg/c

m2)

A.

whi

te b

irch

(st

eam

pre

ssur

e, 2

8 kg

/cm

2)0

:Ja

pane

se l

arch

(st

eam

pre

ssur

e. 2

8 kg

/cm

2 )

Table 2. Nutritional analysis and digestibility of exploded Mosochiku

Nutritional analysis in vitro Digestibility

Samples Steaming DM OM CW o c w Ash DM OM o c w(Mosochiku) t ime (min) (%) % of DM (%) (%) (%)

Unexploded 0 92.4 98.0 94.1 93.2 2.0 9.6 8.0 3.21 93.3 98.0 73.0 72.4 2.0 32.6 31.8 7.12 94.5 98.8 72.3 71.6 1.2 33.8 33.5 8.1

Exploded 4 91.8 99.0 71.1 70.3 1.0 47.8 47.3 25.88 91.9 98.9 81.0 80.1 1.1 48.6 48.7 36.6

16 91.2 98.9 82.3 81.5 1.1 50.0 49.8 39.1

Table 3. Nutritional analysis and in vitro digestibility of exploded materials

Nutritional analysis in vitro Digestibility

DM OM Crude Crude OCW DM OM o c wpro te in fat

(%) (%) ( % ) (%)

(%) of DM

Mixed hey of orchardgrass 85.8 90.9 18.1 2.0 61.9 70.2 68.5 53.7and t imothy

Alfalfa 86.5 89.9 20.1 2.4 46.4 64.0 64.4 31.1

Rice s t raw (unexploded) 86.1 85.1 5.2 1.8 60.9 43.6 43.7 20.9

Rice s t raw (exploded) 90.2 84.6 4.5 2.2 56.8 69.1 75.0 64.2(24 kg/cm2, 4 min)

Bagasse (unexploded)

Bagasse (exploded)(27 kg/cm2, 2 min)

92.0 97.2 - - 93.7 41.6 41.8 39.6

91.9 96.9 - - 77.5 63.3 65.8 57.2

Japanese larch 90.3 99.8 - - 88.4 11.6 12.1 0.6(unexploded)

Japanese larch (exploded) 92.3 99.7 - - 72.1 29.1 29.4 2.4(28 kg/cm2, 4 min)

White b i rch (unexploded) 94.9 93.7 - - 83.5 13.3 13.4 2.8

White b i rch (exploded) 87.4 86.8 - - 51.4 76.5 76.5 60.6(28 kg/cm2. 4 min)

White b i rch (exploded) 25.2 99.8 0.6 3.4 75.8 52.7 54.0 41.0(26 kg/cm2, 4 min)

EXW with P. valioti 40.7 97.2 7.2 0.9 82.7 52.4 52.7 45.4(26 kg/cm2, 4 min,4O°C. 14 days)

to easily digestible materials in a mixture ofthe stomach juice of a sheep and artificialsaliva of McDougall. Exploded Mosochikuand rice straw gave 50% and 75% digesti-bility of organic matter (OM) in comparisonwith 8.0% and 44 % of those in the unex-ploded samples, and 39% and 64% digesti-

bility of organic cell wall (OCW) (unexpiodedsamples, 3.2% and 21%). respectively.Thus, digestibility of Mosochiku EXB andwhite birch EXW is comparable to that ofstandard feeds, orchard-timothy (68.5%)and alfalfa (64.4%) (Table 2 and 3).

313

Digestibility of white birch EXW by cattleand goats in a preliminary investigation alsoshowed a better value (90%) than that of heycube (73%). Body weight of the goats fedwith white birch EXW were the same to thoseof control (Kameoka et al., unpublisheddata). In addition, we recently found(Tanahashi et al., in press) that the culture ofPaecilomyces varioti which was developed by

Forss et al. (1976) to produce microbial pro-tein, with white birch EXW considerablyimproved nutritional quality of EXW (crudeprotein content increased to 7.2%. Table 3)as ruminant feed. Sugars derived from hemi-celluloses, phenolic compounds from lignin,and 5-hydroxymethylfurfural in water solublefraction of the white birch EXW were almostcompletely catabolized by the culture. It isthus concluded that EXB and EXW are suit-able for fermentation and ruminant feed. Itwas also shown that the steam-explosion pro-cess is one of the best pretreatment ofbamboo and woody residues for enzymic sac-charification, and preparation of ruminantfeed and wood chemicals.

Acknowledgement

This research was partly supported by aGrant-in-Aid for Scientific Research (No.59127037) from the Ministry of Education,Science and Culture of Japan.

References

A. Abe, S. Horii and K. Kameoka, J. Anim.Sci., 48, 1483 (1979).

G.T. Tsao, M. Ladisch, C. Ladisch, T.A.Hsu, B. Dale and T. Chuo, “Fermenta-tion Processes” E d . b y D . Perlman,Academic Press, N.Y. (1978).

Jackson, M.G. Feed Sci. Technol., 2: 105(1977)

K. Forss and K. Passinen, Paperi Ja Puu, 9,608(1976).

K. Kameoka et al., unpublished data.

M. Tanahashi, S. Takada, T. Aoki, T. Goto:T. Higuchi and S. Hanai, Wood Re-search, 69, 36 (1983).

M. Tanahashi and T. Higuchi, PolymerApplications (in Japanese) 32, 595(1983).

M. Tanashashi, Wood Research and Tech-nical Note (in Japanese) 18, 34 (1983).

M. Tanahashi and T. Higuchi, Japan Tappi,39, 118(1985).

M. Tanahashi and T. Higuchi, unpublisheddata.

M. Tanahashi, T. Higuchi, H. Kobayashi,Y. Togamura and M. Shimada, CelluloseChem. Technol., in press.

T. Klopfenstein. in “Upgrading Residues andByproducts for Animal”, . ed. by J.H.Huber, CRC Press Inc., Florida, p, 40(1981).

.

Y. Togamura. A. Miyazaki, R. Kawashima,T. Higuchi, M. Tanahashi and K. Kyoto,Jap. J. Zootechnical Sci., 54, 206(1983).

The use of Bamboo as WaterpipesT.N. Lipangile

Wood/Bamboo Project P. 0. Box 570,lringa, Tanzania

Abstract

Tanzania is one of the poorest countries inthe Third World. About 10 years ago theTanzanian gouernment, guided by theNational Political Party, the CCM, introduceda village settlement policy. Around the sametime, the Ministry of Water, Energy andMinerals, started the Bamboo Project in sup-port of the village settlement policy and toreduce dependency on imported materials aswell as to provide water to the rural populationby quickest and cheapest means. Most of theactivities were centered on the use of bambooas a piping material, The use of bamboo in theTanzanian rural life is feasible and about100,000 people are getting water throughbamboo water systems. The whole construc-tion activity is labour intensive carried out atvillage level with the exception of the designwork. The Tanzanian government hasadopted this technology as a viable alternativefor rural water supply and a division has beenformed within the Ministry of Water, Energyand Minerals.

Introduction

3 1 5

The Bamboo Project has been active nowfor a decade in researching and promoting theuse of bamboo as water pipes within Tanzania.We started investigations on the use of locallyavailable materials as water conduits to reducereliance on conventional materials. The usageof these materials should be undertaken withan eye on economisation and reduction of theforeign exchange component in constructionworks. Fields of application could be villagewater supply systems and small scale irrigationworks. Although bamboos have been tradi-tionally used as water conduits in many parts

of the world, scientific information regardingits behaviour as a water pipe is very scant.Morgan (1974) reports the use of bamboopipes in Ethiopia and the Indonesian engineerSudjarwo constructed a six kilometer pipelineon the slopes of the Merapi Volcano, Java. InTanzania the use of bamboo as water conduitswas unknown, although van den Huevel(1981) reports on one village where bamboowas used as a water pipe. The project has sofar constructed 150 km of bamboo pipe lines in28 villages, supplying water to a 100,000people who are benefitted. Though there wasinitial resistance from the Ministry of Wateragainst this “backward’* technology, the pro-ject is gaining more recognition for its activitiesand since July, 1985, it has become a divisionwithin the Ministry. The project is regarded asa good example of the theory of “self-reliance”as expressed in the Ujamaa policy of Tanzania.

Types Of Bamboo

The first bamboo water supply scheme atthe shores of lake Victoria was constructed ofOxytenantera abyssinica and Bambusa vul-garis (Clayton, 1979). In South of Tanzaniavast forests of bamboo are found most of1500 meter a.s.1. The indigenous bamboo isabundantly available here and is very suitablefor water piping. Arundinaria alpina, orthe green mountain bamboo grows gre-gariously but not in clumps (monopodial).The density is about 5,000 stems per hectare.Culms grow up to 18 mtr and show theinternal diameters between 50 - 85 mm.Because the project does not practise clearcutting, the forest regenerates after 4 - 5years. No specific records are available onflowering of Arundinaria alpina in Tanzania.(Wimbush, 1945); the other sympodial

species used in the project is Bambusa vuI-garis which was brought to Tanzania duringthe German colonial time (1890 - 1918). Itis less straight than the green bamboo, andcutting it into right sizes is also more labour-ious. However these disadvantages areoffset by its bigger diameters, up to 125 mmand its greater pressure bearing capacity. It isabundantly found north of lake Nyasa (Fig. 1),where it Is also used in housing construction.When all engineering and preservation prob-lems are solved they can be used satisfactorily.

Measurement to determine variation inbore size along the bamboo stem o fArundinaria alpina. revealed that the portionof the bamboo starting from one meter abovethe ground up to five meters was of uniformbore size and thickness. For a 50 mm (internaldiameter) bamboo pipe there was an averagedifference of 1 mm over the 4 mtr. while for a75 mm pipe this difference was almost nil.Experiments carried out to ascertain pressureswhich bamboo can withstand revealed thatthe material-is capable of taking very highinstantaneous pressures. For Arundinariaalpina values up to 6 bar were recorded andfor Bambusa vulgaris it sometimes reached 10bars. However the pressure withstandingcapability differs very much from bamboostem to stem and that maximum valuesdrop considerably when the stem is exposedto those pressures for longer times. Noparameters could be established whichcan correlate or predict the pressure with-standing capability. From experiencegathered in the field. it was concluded thatthe working pressure for Arundinaria alpineshould not exceed 1 bar and for Bambusavulgaris 2 b a r s . When the bamboo isreinforced by putting wire aroud it. thesevalues-can reach 2 - 3 bars. The low realworking pressure for the bamboo pipe may becaused by the water hammer impact. Theinstallation of water hammer absorbingdevices may lead to enhanced working pres-sure ranges. From discharge - pressuremeasurements conducted at the Hydraulicssection of the Department of Civil Engineer-ing, University of Dar es Salaam. the variationof the friction factor (X) was determined by theDarcy Weisbach equation with Reynoldsnumber (Re) (Fig. 2). The plotted Moodydiagram clearly depicts the values plotted inthe turbulent flow zone. Consequently the use

of the exponential formula would be justified.The values of Manning’s and Hazen-William’sroughness coefficient were determined andfound to vary between 0.013 - 0.016 n and75 - 9O°C respectively. The lower n-valueindicating good node removal and the higherones poor node removal.

Preservation

When burried in the ground as a pipe,unprotected bamboo will deteriorate rapidlyand in the first village constructed it wasobserved that part of the pipes weredestroyed within two months t ime bytermites. It is not feasible to construct the pipeline Above ground. Cattle and people willdamage it easily, while cracks develop rapidlywhen water flow stops. Because forest andvillage are in most cases widely seperated,replacements are not done easily.

The problem of termite attack was solvedby the use of chlorinated insecticides and thechemicals are sprayed in the trench assolutions of 0.5% aldrin or 1% chlordane.Pipe and chemicals are kept at a distance bypartly backfilling the trench before thebamboo pipe is laid. Possible contaminationof the watek through these chemicals wasinvestigated by the Tropical PesticideResearch Institute at Arusha. Tanzania, andthe laboratory of the water chemistry group ofthe Delft University of Technology, theNetherlands. Results showed that no healthhazards arise from the use of these pesticides.(van den Heuvel 1981). Their persistance inthe environment makes them very useful forlong-term protection and since 1977, nofailures due to termite attack have beenreported (Lipangile 1985). In November1984 a case of termite attack was reported inthe first village constructed, Likuyufusi. Thiscontinued occasionally this year, indicatingthat retention values of the pesticide in the soilare becoming less which is in accordance withreported data (Matsumura 1972). Dependingon soil condition, temperature, pH andorganic material a reapplication of the chem-ical will be necessary after 7 to 15 years. Rotbecomes a severe problem in bamboo waterpipes after 3 - 5 years. An early experimentwith tar culms gave good results (up to 8years and not for life), though this was tem-

316

porarily abandoned. Another strategyadopted was the intermittent chlorination ofbamboo water schemes. This killed spores offungi as well. Since starting this practice therehas been a remarkable improvement in perfor-mance for the existing schemes. Moreresearch should be done to determine the con-centration and period of usage. Resuming,present preservation technique involves:a) spraying of the trench with chlorinatedpesticides; b) coating the outside with tar andc) intermittent chlorination.

Extensive research has been carried out toimpregnate the bamboo culm with other pre-servatives and al1 such tests failed because ofthe leaching of the preservative into the water.It is thought that enhanced durability shouldbe possible by coating the pipe (inside andoutside) with epoxy materials. W h e nnecessary a fungicide (copper sulphate) couldbe impregnated in the culm before applyingthe coating. It has been observed that dur-ability of the bamboo pipe is increased by: a)clean water; b) careful design and con-struction aimed at a water saturated pipe;and c) construction of schemes at higher (=

colder) altitudes. Taking these observationsinto account, present preservation techniquesshould protect the pipe for more than 10years.

Al1 the bamboo water schemes con-structed so far are by gravity flow. The intakeis normaIly a weir across a perennial stream.The design of the scheme is mostly based ona 24-hour flow demand from intake tostorage tank and for the distribution systemon a peak-flow demand. Breakpressurechambers are constructed where the headexceeds the pressure ratings of the bamboopipes.

The pipe making and laying processinvolves the following:- Mature stems of over 3 years age are cut

in the forest. Presently the project usesonly one forest near Mbeya (Fig. 1)

- 4 meter pieces are t ransported to anearby river.

- the nodes are partly removed and thestems are submerged for at least threemonths in the river to allow desapping. Iffresh bamboo are used, the water will geta horrible smell.

FIG. 1: MAP OF TANZANA_

SAL A AM

B: BAMBUSA VULGARISX : OTHER REPORTED PLACES OF BAMBOO OF-

UNKNOWN QUANTITY

317

0 0 0 0

0 0 0 0 0 0

318

- from this centralized pond the bamboosare transported to the village constructionsites.

- here again the bamboos are stored in apre-constructed pond.

- the bamboo pipes are reinforced withgalvanized wire.

- the butt-ends are sharpened by knife to fitthe joint.

- nodes are manually removed by drillingwith a 2.5 mtr. long steel rod on whichaugers of different sizes (to fit the differentdiameters of the bamboo) can bescrewed.

- bamboos are air-dried before they aresubmerged in a boiling tar solution for 2-3minutes. Coating is only applied on theoutside.

- After drying the pipes are transported tothe trenches.

- the trenches have been sprayed with a0.5% solution of afdrin and are partlybackfilled.

- the pipes are laid and jointed by pieces(20 cm) of polyethylene, class B (6 bar).

- Before inserting the bamboo pipes thejoints are slightly heated to allow expan-sion. The pipes are hammered into thejoints, which will form upon shrinkage aleak-proof joint.

- the trench is backfilled with some soil. Ontop of this again afdrin solution issprayed.

- finally the whole trench is backfilled.In this construction methodology all fit-

tings, T’s, connectors, reducing sockets,breakpressure chambers and domestic pointsused are of conventional materials.

Maintenance

During construction period two villagersare selected and trained in construction activ-ities. After completion of the scheme theyreceive a supply of spare bamboos and othermaterials to enable them to carry out repairworks. They are also supplied with a stock ofchlorine lime. Each month they are obliged tosend a maintenance report to the HQ atIringa. In this report they should indicate thenumber of failures during previous month (1failure = 1 pipe of 4 mtr has been replaced)

and the cause of these failures. They alsoreport depletion of stock. From these reportsthe average number of replacements receivedin a month/per scheme can be calculated.Failures could be due to: - the use of ungafvanized wires for rein-

forcement and rusted wire, the plugsused to fill the insect holes often becomeloose, especially during the first months.

- Excessive water pressure developed(Msimbe, 1984).Very seldom termite attack is reportedbut, if the bamboos rot, then the wholeoperation has to be repeated.

Economics

A 63 mm bamboo pipe is about 4 timescheaper than a focally purchased plastic pipeof the same diameter (Lipangife 1984). Theeconomics of bamboo pipes were estimatedby an independent evaluation mission to theBamboo Project, paid for by the SwedishInternational Development Agency (SIDA).They came to the conclusion that bamboopipes are cost competitive both in terms offinancial - and economical annualized costs(Broconsuft 1983). From these cost analysesit is apparent that transport contributes greatlyto the total costs (up to 50%). This can bereduced considerably by using bamboos inthe nearby forests and by exploiting morethan one forest. The economic advantage ofa bamboo pipe depends also on what size ofpofythene pipe it is going to replace. Msimbe,(1985) reports that at low gradients increasedflows will be conveyed more economically bybamboo pipes.

References

BROconsult. 1983. “Wood - Bamboo Pro-ject. Final Report”. Prepared by evalua-tion mission to the Bamboo Project oninstructions of the Swedish InternationalDevelopment Association (SIDA). Stock-holm.

Clayton W. D. (1979, “Flora of tropical EastAfrica”, Ministry of Overseas Develop-ment. London.

319

Heuvel K. van den 1981, “Wood and Bam-boo for rural Water - Supply a Tanzanianinitiative for self-reliance-“. DelftUniversity Press, the Netherlands.

Lipangile T.N. (1984), “Wood - BambooProject”. Rural Hydraulic DevelopmentConference, Marseille.

Lipangjle T.N. 1985, “Bamboo Water Pipes”.Waterlines 3.

Matsumurra F. et al. 1972, “Environmentaltoxicology of pesticides”

Morgan J. (1974), “Water pipes from bambooin Mezam Tefari, Ethiopia”. AppropriateTechnology Vol. 1.

Msimbe L. (1984), “Wood - Bamboo tech-

( !" Further details from the anthor - Eds)

nology development”. Regional WaterEngineers Conference Tanga, Tanzania.

Misimbe L. 1985, “Wooden and bamboomaterials in the implementation of waterfor all Tanzanians by 1991”, 11th WEDCConference “Water and Sanitation inAfrica”, Dar es Salaam.

University of Dar es Salaam 1980, “Labora-tory investigations for determininghydraulic design for bamboo P and wood-stave pipes” Consultancy report preparedby the Laboratory of Hydraulics, Univer:sity of Dar Es Salaam.

Wimbush S.H. 1945, “The African alpinabamboo”, The Empire Forestry Journal24’.

320

CCA Impregnation of Bamboo -Leaching and Fixation Characteristics

J. W . Slob, P. F. Nangawe, E. de Leer’ and J. Donker !

Wood/Bamboo Project, P. 0. Box 570, Tringa, Tanzania*Water Chemistry Group, Delft University of Technology,

P.O. Box 5029, Delft, The Netherlands

Abstract

Leaching tests carried out on CCA(Copper. Chrome, Arsenic) impregnatedArundinaria alpina bamboo by Boucheriemethod, revealed that As was leaching exces-sively. An average of 15 % Cu, 17% Cr and34 % As could be removed by submerging 2cm bamboo rings in water. Concerning totalsalt retehtion, Boucherie impregnation wassuccessful. An average of 12.0 kg salt percubic meter of bamboo was retained. Theleaching results were in marked contrast toearlier laboratory findings with CCA impreg-nation of bamboo sawdust. These experi-ments showed that good fixation is possiblewhen sufficiently high (= 5 - 10 %) concen-trations of CCA are used. Differences areexplained by discrepancies between the path-ways of fixation that are followed. Within thebamboo culm, fixation is mainly the result ofthe formation of Cu - Cr - As complexes inthe vascular bundles. From these vascularbundles the metal ions diffuse slowly to thesurrounding tissue. In sawdust, fixation takesplalce through the formation of CCA com-plexes with the bamboo constituents - cellu-Iose and lignin-. In this process fixation ofchromium onto cellulose and lignin is the key-step.

Introduction

Chromated Copper Arsenate (CCA) for-mulations have been in use as commercialwood preservatives for more than 45 yearsand these are the most effective wood preser-vatives, first developed by Kamesam in 1933.He conceived that copper sulphate, a provenfungicide, and arsenic pentoxide, a proven

insecticide, in combination with potassiumdichromate, a fixing agent, should contain theproperties of an excellent wood preservative.Since the early development of Ascu, as thefirst copper-chrome-arsenic preservative wascalled, others have become available on acommercial scale. These included Tanalith C,Celcure A and Boliden K33. They differ inratio of the used components. Copper is usedin the form of copper oxide or copper sul-phate. Chromium can be found as chromiumtrioxide, sodium chromate or potassium di-chromate. Arsenic is used as arsenic pen-toxide of different water of crystallization. Theexperiments described in this paper werecarried out with Tanalith C. Its composition isgiven in the experimental part of this paper.

From the available data all of the CCAformulations appear to be excellent woodpreservatives, especially for soft woods. Inhard woods, early failures may occur. Thewide spread use of these chemicals in woodprotection was greatly encouraged by itsadherence property to the wood. Arsenault(1975) reported the use of CCA treatedtimber in all kinds of structures where resis-tance to leaching and high fixation degreeswere needed and proven i.e. cooling towers.water storage tanks, flumes, mushroom trays,tomato and grape stakes. Dunbar (1962)described the fixation of water-borne preser-vatives in cooling tower timber. Henshaw(1978) reported the fixation of copper,chrome and arsenic in softwoods and hard-woods. The leaching of copper, chrome andarsenic from CCA impregnated poles wasreported (Evans, 1978). All of them are goodfixatives with low leaching rates.

With this background information, theBamboo Project in Tanzania was started toinvestigate the use of CCA as a preservative

321

for bamboo water pipes. The aim of theproject is to develop a technology whichreplaces imported hardware elements invillage water supply works by materials madeout of locally available wood and bamboo.Bamboo could be a viable piping materialwhen its durability could be guaranteed formore than 10 years. The well-defined com-ponents of the CCA preservative, the knowntoxicity and tolerance standards, the fixationproperties and its protective working againsttermites and rot could make it an excellentpreservative for bamboo water pipes if indeedprotection and fixation could b e proven forthis case. Unprotected bamboo water pipesburied in the soil will be destroyed rapidly bytermites (van den Heuvel, 1981). By sprayingthe trench with chlorinated insecticides (aldrinor chlordane) this problem could be over-come. Since the project started using theseinsecticides in 1977, no damage due to termiteattack has been recorded (Lipangile, 1985).However rot is not prevented in this bray.Service data records show that without anyadditional protection bamboo pipes must bereplaced within one to five years. Present pre-servation technique involves spraying thetrenches with chlorinated insecticides, coatingthe outside with tar and intermittent chlorina-tion of the constructed schemes (Msimbe,1985), while careful design and construction- aimed at 100% filled pipes - may add tothe life-span of the pipe. CCA impregnationof the bamboo culm would enhance life-span,reduce costs and facilitate the manufacture ofthe bamboo pipes.

Very little data is available on the use ofCCA as a preservative for bamboo. In areport of the United Nations (1972). recom-mendations were made for the protection ofbamboo in use under different conditions. Afew other publications mentioned the advis-able solution strength of CCA for bambootreatment. Wimbush (1945) gives2%, Bleyen-daal (1978) 10% and Purushotham et al(1965) 8%. The last author also reported thata retention of 5 - 6 kg/m3 is needed for a 10- 15 year protection. No data was availableon the leaching and fixation of CCA in bam-boo: Van den Heuvel (1981) reported thefirst part of this research on CCA impreg-nation of bamboo water pipes. The aim of theresearch was to investigate if CCA could besafely applied in bamboo water pipes. CCAimpregnation of bamboo sawdust was carried

3 2 2

out and assessed for leaching and fixationcharacteristics. According to these laboratoryfindings, field trials were performed with CCAimpregnation of bamboo culms by Boucheriemethod. Most chemical analyses wereperformed in the Delft laboratory, while fieldexperiments were carried out in Tanzania.

Results and Discussion

Type of bamboo: When not otherwisementioned, all experiments were conductedwith the bamboo Anmdinaria alpha, alsocalled the green African mountain bamboo. Itis the species most abundantly available inTanzania and because of its size (internaldiameter 50 - 75 mm) and straightness, it isvery suitable as a water pipe.

Type of CCA: All experiments describedin this paper were carried out with Tanalith C.A CCA-type preservative had the followingcomposition (as % w/w) :

45% potassium dichromate -molar ratio Cr 2.2; 35% coppersulphate

- molar ratio Cu 1; and20% arsenic pentoxide -molar ratio As 1.1.

It resembles closely the CCA type C, definedaccording to the American Wood PreserversAssociation standard PS-74. This standarddefines the molar ratio for CCA type C asCr/Cu/As as 2.0/1.0/l. 1.

Tanalith C was chosen because it is theCCA preservative most widely used inTanzania.

Chemical analysis of copper, chro-mium and arsenic: Copper and chromiumwere determined according to standard proce-dures for the atomic adsorption technique.An air-acetylene flame was used. TheTanzanian laboratory used a Pye Unicam SP9, the Delft laboratory the Varian Techtronic1100. When the concentrations became verylow or the matrix influences high, the flame-less technique was used in the Delft labora-tory. The instrument. a Perkin Elmer S300.Arsenic was determined in the Delftlaboratory by the normal hydride generationtechnique. was atomized in a quartztube with an air-acetylene flame and mea-sured with the Varian Techtronic 1100. Atthe Government Chemist laboratory, Dar esSalaam. was led through a solution of

CrAsO4,

PH

silver diethyldithiocarbamate (SDDC) and thered coloured complex measured at 540 nmwith a spectrophotometer.

Determination of Cu, Cr and As inbamboo tissue: The total amount ofcopper, chromium and arsenic in the CCAtreated bamboo was determined throughdigestion. Pieces, varying from 3 - 6 grams,were dried at 105°C and accurately weighed.They were transferred into glass tubes( , 4.0 cm x 30 cm), 25 ml of concentratednitric acid was added and the tubes wereslowly heated in an aluminium heating blockat 40° - 6O°C. After a few hours, another 25ml of conc was added and heatingcont inued at 16O°C The digestion wasstopped when all the bamboo had dissolvedand the evolution of nitrous fumes hadstopped. The solution was transferred quanti-tatively to a measuring flask and water addedto make up a final volume of 100 ml. Concen-trations of copper, chromium and arsenic weremeasured with the techniques mentioned andexpressed as grams per kg of bamboo tissue.

CCA fixation onto bamboo sawdust:The CCA reaction in wood is a fixation reac-tion involving the reduction of hexavalentchromium to trivalent chromium, followed bythe formation of a complex mixture of insolublesalts. According to Dahlgren and Hartford(1972 II and III) the final equilibrium fixationproducts are ion-exchanged Cu to the wood,

a n d

although highly basic chromic chromates,persist for a long time. Depending on the pH,the various exist in equilibrium withone another as follows:

+

+ The reduction of chromium than takes placeaccording to the following reactions

+ + 6e +

+ + 3e +

+

The last reaction only takes place underalkaline conditions and is of no interest for theC C A - wood/bamboo system. During thecourse of chromium reduction, the pH willincrease due to the depletion of ions. pHincrease in time was measured for the CCA- bamboo system. 8 grams of bamboosawdust was mixed with 8 ml of CCA solutionof different strength (2%, 5% and 10%). Thesamples were placed in the dark and the pHmeasured in time with a flat-membrane pHelectrode, The results are given in fig. 1, Thedate clearly indicate that there is a sharp initialrise in pH (pH of a 5% CCA solution = 2).An instant change in proton activity of thismagnitude cannot possibly be explained by

Fig. 1. The pH changes during fixation of CCA onto bamboo sawdust for different concentrations of CCA

3 2 3

chromic acid oxidation of bamboo tissue.Dahlgren and Hartford (1972 I) observed thesame phenomenon for wood, although theeffect was not so pronounced. The pH in-creased from 2.03 to 2.55 after 3 minutes for a5% Tanalith C solution on pine wood. He attri-buted this to an absorption of chromic acidonto the wood constituents. However, inTanalith C, the bulk of proton activity is gen-erated through hydrolysis of arsenic.pentoxide, producing arsenic acid ,which will be partially ionized. Bamboo tissuemust be capable of taking up ions (buffercapacity) resulting in the large instant pHincrease, although it cannot be ruled outthat rapid cdmplexing of chromium andarsenic anions contributes to the observedeffect. The observed oscillating pH effects atthe end of the fixation time can be attributed toconversion reactions of already precipitatedmaterials into more stable compounds.Dahlgren and Hartford (1974 IV) postulatedthe conversion of primarily formed acidic cop-per arsenates into basic copper arsenatesunder release of arsenic acid, which in its turnreacts with the earlier formed chromic chro-mates. Pizzi (1981 I and 1982 IV) could notfind copper arsenate complex in precipitatesobtained after reaction of CCA type C withwood and i ts separate const i tuents -glucose/cellulose and guaiacol/lignosuI-phonate - and he postulated that theoscillating pH at the end of the fixation time

was due to rearrangement of lignin complexunder influence of the slow release of

For arsenic fixation, chromium reduction isessential. AI1 the arsenic is precipitated as

which can form complexes with ligninor stay loosely bound to cellulose (Pizzi, 1982III). For chromium reduction, it is necessary tohave: 1) sufficient ions - during chro-mium reduction is consumed causing theslow pH increase; 2) sufficient oxidizablematerial - chromium reduction is only possi-ble when another compound is oxidized.

The formation of precipitates is favouredby: 3) a high final pH -- the higher the pH,the m o r e insoluble the complex. Dahlgren(1975) gave a pH of 6, above which all saltswere precipitated; 4) a low ionic strength -

(solubility product) is the product of activ-ities. The higher the ionic strength, the lowerthe coefficient of these activities, the higherthe concentrations.

To verify the above assumptions, bamboosawdust was treated with different concentra-tions of CCA (2%, 5% and 10%) underaddition of acetic acid (HAc) as a source ofprotons and sugar as an easily oxidizablematerial. The redox potential (E) and the pHwere measured with flat-bottom electrodesduring a two month period. Samples werekept in the dark. pH and E are plotted againsteach other in Figs. 2, 3 and 4 for the differentsolution strengths and the different additions.

Fig. 2. E versus pH graph for the fixation reaction of 2% CCA (and different additions) onto fixation reaction.The straigth drawn line depicts how E changes with pH in a pure 2% CCA solution.

324

PHFig. 3. E versus pH graph for the fixation reaction of 5% CCA (and different additions) onto bamboo sawdust.The straight line depicts how E changes with pH in a pure 5% CCA solution (for details, see text).

PHFig. 4. E versus pH graph for the fixation reaction of 10% CCA (and different additions) onto bamboo sawdust,The straight line depicts how E changes with pH in a pure 10% CCA solution.

The straight lines in these figures depicthow E changes with pH when no chromiumreduction takes place. The further the pointfrom this line, the more chrome VI has beenreduced. After this fixation time the sawdustwas washed twice with 100 ml deionizedwater to determine the amount of unfixedcopper, chromium and arsenic and the con-centrations in the washing liquid were mea-sured. Table 1 gives the values of washed out

copper, chromium and arsenic in mg pergram bamboo and as a percentage of totalcopper, chromium and arsenic retention.Table 1 also shows that with a low loading ofCCA on bamboo, the fixation was verypoor. A 2% Tanalith C solution gave aleaching of 13% for Cu, 30% for Cr and29% for As. Dahlgren and Hartford (1975 V)reported the same phenomenon for Douglasfir. Ponderosa ‘pine and to a lesser degree

3 2 5

Table 1. Leaching of copper (Cu), chromium (0) and arsenic (As) from CCA impregnatedbamboo sawdust, using different concentrations of CCA and different additions for

impregnation.

2% CCA + 8% sugar + 0.2M HAc + l.OM HAc + 4.OM HAc

copper 0.30 - 1 3 % 0.37 - 16% 0.15 - 6 % 0.63 - 27% 0.90 - 39%chromium 1.22 - 30% 0.67 - 16% 0.32 - 8 % 0.63 - 15% 0.99 - 24%arsenic 0.87 - 29% 0.63 - 21% 0.51 - 17% 0.66 - 22% 0.95 - 32%

5% CCA

copper 0.16 - 3 % 0.18 - 3 % 0.18 - 3 % 0.92 - 16% 2.18 - 37%chromium 1.20 - 12% 0.26 - 3 % 0.21 - 2 % 1.61 - 16% 3.68 - 36%arsehic 0.14 - 2 % 0.16 - 2 % 0.18 - 2 % 0.79 - 1 1 % 1.74 - 23%

10% CCA

copper 0.31 - 3% 0.24 - 2 % 0.32 - 3 % 0.98 - 8 % 4.21 - 36%chromium 2.06 - 10% 0.21 - 1 % 0.94 - 5 % 3.22 - 16% 10.51 - 5 1 %arsen ic 0.24 - 2 % 0.19 - 1 % 0.23 - 2 % 0.94 - 6 % 3.02 - 20%

All values are expressed as mg metal leached per gram sawdust.The percentages are of total retention of the metal ion.

Southern yellow pine when treated with 2 -2.5% preservative solutions, although hementioned unexpectedly high As leachability.Doubling the concentration also gave normalleaching rates. When we interpret the leach-ability of Cu, Cr and As for the differentsolution strengths with the results drawn inFigs. 2, 3, and 4, we can conclude that thesehigh leaching figures for the 2% solution aredue to poor chromium reduction. The figuresalso show that addition of sugar resulted in

more chrome reduction at the end, althoughthe reaction did not proceed any faster. Thefixation of chromium was improved for allsolution strengths when sugar was added(Table 1). Addition of acetic acid solutionsgave 1 M and 4 M a larger chrome reduction(Fig. 5). However, because of the low final pH(pH 5) and the high ionic strength, precipi-tates were poorly formed, causing highleaching rates (Table 1). From Fig, 5, it canalso be concluded that when is in excess. a

5 % C C A

+Q2MH4c

+ 4 MHAC

Fig. 5. E versus pH graph for the fixation reaction of 5% CCA, dissolved in different concentrations of acetic acidonto bamboo sawdust.

326

buffer of pH 4 - 5 will be formed (the naturalpH of bamboo}. When we used a smallerquantity of HAc (0.2 M HAc), chrome reduc-tion will be somewhat quicker, while the endpH hardly differs from that of the CCAsolution without HAc. This indicates that theadded protons were used. Chrome fixation isimproved for all solution strengths.

From the prevailing data it is obvious thatthe availability of H ions and oxidizablegroups is not a hindrance for chrome reduc-tion. When this should be the case, leach-ability of As for the 5% and 10% solutionsshould be the same or higher then for the 2%solution (the amount of bamboo was keptconstant). Final pH and ionic strength doinfluence the sofubility of the complexes, butin normal reaction circumstances, p h is suffi-ciently high and ionic strength low, to guaran-tee low solubility .

With the model of fixation as postulatedby Dahlgren and Hartford (1972 II and III) andDahlgren (1975). it is difficult to explain theresults obtained. The mere formation of preci-pitates as model of fixation appears verysimple. Our date support the results of Pizzi.Pizzi (1981 I, 1982 II, III and IV) based hismodel on the reactions of hexavaient chro-mium with the different wood constituents. Heconcluded that this reaction takes place inthree different reaction zones depending onPH.

First zone: Low initial pH,

the dominant chromium anion

+ cellulose kads - cellulose]complex

+ lignin - lignin]complex

Second zone: pH has increased, the reacting chromium anion

+ cellulose kads - cellulose]complex

+ iignin - iignin]complex

Third zone: further pH increase albeit slow, all removed from solution

- cefiuiose] kred - Cellulose]

+ cellulose

For the system, the reactionrates (k) were determined for the differentzones (Pizzi 1981 I). For the first zone kads >

This gives at the end of the first zone more complexed on cellulose. For the second zone

The reaction of the second zonehardly adds to the total amount of -cellulose complex. Reduction of chromiumtakes place through a rapid formation of - cellulose complexes in the first zone, fol-lowed by a “slow” in situ reduction on cellu-lose. The - cellulose complex can releasetrivalent chromium into the solution where itforms complexes with arsenates. The secondzone kads hardly contributes to the total amountof formed. First and second zone reactionsare rapid compared to the kred of the -cellulose complex. As was earlier mentioned,the pH of the CGA/bamboo system risessharply at the beginning (Fig. 1). The effect ismore pronounced for the 2% solution then forthe 5% and 10%. Total chromium reductiondepends on the length of time of the first zone.First zone reactions continue as long as the

is the dominant chromium anion.Due to the sharp initial rise in pH for the CCA-bamboo system will be rapidlyr e p l a c e d b y HCr04- (see eq. 1).Consequently only little will be complexedon cellulose and thus only little willbe available for chrome arsenate com-plexes, From Fig. 1 it can be concluded thatthe 2% solution forms the least causingthe high leaching rate of arsenic.

The effects of adding sugar and ionscan also be explained by this model. Additionof sugar merely raises the initial concentrationof the complexing cellulose/sugar. Because ofthis higher concentration, more will becomplexed on cellulose/sugar and arsenicleaching will be reduced (sugar also reduces

Figs. 2, 3 and 4 show that in case ofsugar addition, the reactions do not proceedfaster but more will be formed at the end.This is in accordance with the presentedmodel. Addition of in the form of 0.2 MHAc gives for the 2% CCA solution a lowerinitial pH (Fig. 6). extending the period of thefirst zone reactions and therefore enhancingthe total amount of chromium reduced.Arsenic leachability will be reduced (Table 1).Extensive washing of bamboo sawdust beforeCCA impregnation (sap removal) also giveslower leaching rates. Washed and unwashedbamboo sawdust was impregnated with 5%CCA solution. After four weeks arsenicleaching was determined. The washedbamboo gave very low leachability (1.1%).while for the unwashed bamboo, this figure

327

I I I I I1 10 100 1000

fixatian time (hrs)Fig. 6. The pH course during fixation of 2% CCA (with and without HAc) onto washed andunwashed bamboo sawdust.

1o = 5% CCA , unwashed sawdust

+= r, , washed I,

2001 . .

Fig. 7. E versus pH graph for the fixation reaction of 5% CCA onto washed (sap removed) andunwashed bamboo sawdust.

was 10% .-From Fig. 6, it can be seen that sapremoval causes a lower initial pH. More chro-mium will be reduced according to the modelpresented earlier. This is verified by the E -pH diagram (Fig. 7). Washing may also resultin a lower ionic strength, favouring the forma-tion of precipitates.

The model presented does not offer anexplanation for the behaviour of copper andchromium leachabilities. According to Piui,

- lignin complexes are quite stable andnot. easily leached out. Our data indicates that

is necessary to a certain extent for fixation

of chromium into the bamboo (through the for-mation of chromic - chromate - lignin com-plexes). It is recalled that Pizzi obtained hisresults with guaiacof and lignosulphonate asmodel compounds for wood fignin. whichis present in soft wood mainly as guaiacylunits and in hard woods as guaiacyl andsyringil. The lignin of bamboo is a typical grassIignin of mixed dehydrogenation polymers ofconiferyl-, singapyl- and p-coumaryl alchohois(Higuchi and Kawamura, ‘1966; Nakatsubo etal, 1972). Apparently the type of complexesand the rate of complex formation will be

328

effected by this difference. Piui (1982 II)reports that 10 - 20% of the Cu is fixed ontolignin as complex and the remaining ision-exchanged fixed to lignin and cellulosewith a preference for lignin. No explanationcan be offered for the observed lower leach-ability of copper in case of higher solutionstrengths and addition of ions. Sugar hasno influence, probably indicating that isnot involved in copper complexing. A lowerinitial pH seems to favour Cu complexing ontobamboo.

From all the above, it can be concludedthat the fixation mechanism of CCA ontobamboo resemhles closely the fixationmechanism of CCA onto wood, the maindifference being the high initial rise of pH (dueto the buffer capacity of bamboo). This causesfor low solution strengths a poor chromiumreduction and therefore high leaching rates ofarsenic. Although the data presented in TableI gives the amount of easily removed (andthus not precipitated or complexed) copper,chromium and arsenic, severe leachingconditions will lead to additional removal ofthe different compounds. Tests carried out,representing severe leaching conditions(bamboo sawdust was put into a column andeluted with 10 1 of water), indicate that for a2% CCA solution + 0.2 M HAc still as muchas 24% copper, 11% chromium and 12%arsenic could be removed after washing. Forthe 5 and 10% CCA solution these figuresrespectively were 15% - 2% - 6% and 2%- 5 % - 3%, again in favour of the highsolution strengths.

CCA impregnation Of BambooPipes by Boucherie Method

Liese (1980) and Tewari (1981) describedthe different methods to impregnate bamboowith water soluble chemicals. Van denHeuvel (1981) reported the experimentscarried out by the Tanzanian Bamboo Pro-ject to impregnate CCA into the bambooculm by different methods. He reported thatmethods using air-dried bamboos failedbecause of the high percentage of cracking.Steeping of fresh bamboos, hot and coldbath and sap displacement techniques wereextensively tested. The steeping method gavesatisfactory salt retentions (5 kg/m3), butradial distribution was very poor. The inner

part of the culm was poorly treated and theup-take through the inner wall was higherthan from outside. However, the main dis-advantage of the’ steeping method was thecrystallization of the salt on the inner- andouter culm wall, giving rise to health hazardsduring handling and usage, Steepingmethods tested on bamboos with the partitionwalls intact were not successful because ofthe low retention of the CCA. Sap displace-ment techniques gave poor longitudinal distri-bution, al though retent ion at . the butt-treatment end was sufficient. For furtherexperiments, i t was decided to use themodified sap displacement technique, namelythe Boucherie method. Boucherie impreg-nation was carried out using gravity pressure.In the area where the Arundinaria alpha(green African mountain bamboo) grows,selection of a suitable site was easy. Thesupply vat was placed on top of the hill andconnected through a 12.5 mm plastic hosewith the distribution system at the foot of thehill. The gravity pressure applied was 20 m.For research purposes three separate systemswere installed to run the different tests con-currently. Each of the systems had five con-nections for bamboo. Fig. 8 gives in sche-matic drawing the distribution system. Themost difficult part of the Boucherie installationwas the connection between the bamboo andthe installation (the *‘cap”). We used a pieceof polyethylene, class B 0 63.5 mm, insertedin an ordinary poly connector. The capoperated well and was leak-proof when suit-able (i.e., with the right diameter) bambooswere selected. As it was the aim to investigateretention, distribution and leaching, the instal-lation was sophisticated enough. However forlarge scale operations, a cap should bedeveloped which makes coupling anduncoupling easier and more rapid and whichfits different diameters of bamboo. Boucherieimpregnation was carried out with 5%Tanalith C solution. This solution was chosenfollowing the results of bamboo sawdustimpregnation. The use of a 10% solution ledto rapid blocking of the vessels. .Bamboos, 4m long, were treated, varying the treatmenttime. The normal procedure was over-night (O/N) treatment. Before leachingexperiments were conducted, the bambooswere stored for more than three months in ashed. They were covered and kept wet.

329

Fig. 8. Boucherie installation (gravity fed pressure).

Retention and distribution: Retentionvalues (as kg salt/m3 bamboo) were calcu-lated from the -concentrations of copper,chromium and arsenic as found in the diges-tion experiments. When the first leaching ex-periments were performed, the amount ofsalt leached out was added. The tissuedensity of -the Arundinaria alpina was calcu-lated to be 0.66 10” kg/m3. The averageretention for a 5% CCA solution was 12.0kg/m3. This was calculated from 23bamboos, the standard deviation being 4.3. Itis suggested that expressing retention valuesas kg salt/m3 bamboo (as is the international

practice in the wood preservation) is not verypractical. Densities differ from stem to stemand species to species, while measurementsof volume are laborious. It would be more con-venient to use gr salt/kg bamboo. This gives anaverage retention value of 18.1 g CCA per kgbamboo (st.d. 6.6). Table 2 shows theaverage retention of copper, chromium andarsenic (g/kg bamboo) and their molar ratioswithin one stem. The last data clearly indicatesthat the salt composition has changed consi-derably during the Boucherie treatment. Theamount of arsenic retained in the bamboo islower compared to the original solution.

Table 2. Average retention of copper (Cu), chromium (Cr) and arsenic (As) for a number ofbamboos and their respective molar ratios.

Retention (gr/kg bamboo) Molar Ra tio’sBamboo Cu (st dev) Cr (st dev) As (st dev) c u Cr As

1 1.05 40.20) 2.67 (0.89) 0.85 (0.20) 1.5 4.5 1.02 1.31 (0.43) 2.38 (0.65) 0.97 (0.18) 1.6 3.5 1.03 1.14 (0.50) 1.86 (0.65) 0.77 (0.16) 1 . 7 3.5 1 . 04 1.02 10.35) 4.51 (1.72) 0.92 (0.14) 1.3 7.1 1.05 0.93 (0.23) 2.13 (0.51) 0.95 (0.32) 1.2 3.3 1.06 A’ 2.13 (l.15) 1.61 11.21) 0.88 (0.59) 2.9 2.7 1.0

B 1.92 (0.971 1.99 (0.62) 1.12 (0.18) 2.0 2.6 1.07 A 3.61 (2.30) 3.96 (1.64) 2.22 (0.511 1.9 2.6 1 . 0

B 2.81 (1.57) 2.82 (l.31) 1.50 (0.26) 2.2 2.7 1.08 A 1.15 (0.38) 2.39 (0.65) 1.85 (0.43) 0.7 1.9 1 . 0

B 3.04 (2.20) 2.36 (1.25) 1.39 (0.42) 2.5 2.4 1.0

TANALITH C - 0.9 2.0 1.0

!" A indicates that samples were taken 50 - 100 cm from butt-treatment-end.B samoles were taken 250 - 300 c m from butt-treatment-end.

3 3 0

For copper this is reversed (copper is bestretained). From the large standard deviationsof average retention of the different com-pounds within one stem (Table 2), it can beconcluded that longitudinal distribution is veryunequal throughout the culm. Fig. 9 depictshow retention increases with time for the dif-ferent parts of the culm. It is seen that a certainlength of time (the Minimum Treatment Time= MTT) is needed to guarantee sufficientretention throughout the culm. From the samefigure it can be concluded that arsenic passesmost rapidly (so fixes most poorly), whilechromium fixes best. The uptake of coppercontinues for the longest period, indicatingthat copper diffuses best. The MTT dependson bamboo stem, species of bamboo, pres-sure applied and solution concentration. It iseasily determined by measuring the specificgravity of the effluent preservative (whichshould closely resemble that of the originalsolution). Not surprisingly, it correlates wellwith the flow velocity of the preservativethrough the culm. It was observed that flowvelocity decreases during treatment time. Thiswas true not only in the case for CCA solutionsbut also when water was flushed through thestem. Initial flow velocity is strongly reduced inaged stems and will also drop considerably ifthe period between cutting and treatmentis prolonged. We failed to impregnate bambooby Boucherie method three days after cutting.

For good treatment the time between cuttingand impregnation should be as short aspossible.

MTT longitudinal distribution will not bedetermined by distance to the butt-treatmentend and longitudinal distribution is not equal.Large differences are observed (standarddeviations in Table 2), but they do not corre-late with the distance to the butt-treatmentend. These differences are explained by thefact that complexes of precipitates areformed in the vessels (crystal growth). Itis also clear from Fig. 9 that when the MTT isobserved, longer treatment time would notenhance retentions. Radial distribution wasinvestigated using rontgen-scanning tech-niques. Energy dispersive rontgen-spectrawere made from different parts of the bam-boo. Fig. 10 shows the spectra for a vascularbundle of untreated and treated bamboo andFig. 11, for the parenchyma tissue for dif-ferent energies. From these spectra it can beconcluded that the bulk of the salt is retainedin the vascular bundles and gradual diffusionto the surrounding tissues takes place (todetect the metals in the parenchyma tissue,higher energies had to be used). From theseresults it is obvious that the outer part of theculm is better protected due to the higherdensity of vascular bundles in this part. Theresults support the idea that retention andlongitudinal distribution is mainly dependent

treatment time (hrs)

Fig. 9. Retention of as function of time determined at 3 m from thebutt-treatment-end. The dotted line predicts how retention will increase near the butt-treatment-end.

331

A s

Fig, 10, Rontgen spectrum of treated and untreated Fig. 11. Rontgen spectrum of parenchyma tissue ofbamboo. The scan taken in a vascular bundle. treated bamboo using different energies.

...

---

teaching time (hrs)

Fig. 12. Leaching of C u , Cr and As from bamboo beakers (I) and 2 cm bamboo rings (II).

on formation of Cu - Cr - As complexeswithin the vascular bundles.

Leaching and fixation: To investigateleaching patterns. three kinds of experimentswere conducted. In the first, pieces of CCAtreated bamboo were placed in a glasscolumn ( 10 cm x 50 cm). The sawn endswere sealed with a silicone kit. The columnwas filled with water and this water in timeanalysed for copper, chromium and arsenic.In the second experiment rings of 2 cm were

placed in water. This time the ends were notsealed. The third experimental set-upsimulated most closely the use of bamboo aswater pipe. Water was circulated with a pump(so under pressure) through the bamboo.From total water volume, content of the bam-boo pipe and discharge, it could be calculatedhow many meters of pipe line correspondwith one hour of pumped circulation. Figs. 12and 13 show the characteristic leachingpatterns for the different experiments. Leach-

332

'1

2 6 10 14 18 22

circulation time (hrsj(lhr = 35 mtr pipe)

Fig. 13. Leaching of Cu, Cr and As from bamboo pipes through pumped water circulation.

ing is most severe in experiment II, due to the is only dependent on the concentration ofhigh surface/tissue ratio deliberately caused CCA in the bamboo; r = k CCA, r being theby not sealing the ends. After 20 days of sub- leaching rate and k the first order rate con-merging in water, leaching seems to have ter- stant. Because CCA is present in largeminated for these experiments. Percentages excess, the CCA concentration may beof totally leached copper, chromium and regarded as constant during the leachingarsenic were determined from these experi- experiment I. This gives a pseudo zero-orderments II. For copper. the values ranged process. The leaching rate (r). mg/kg hr, andf r o m 5 - 2 8 % . a v e r a g e 1 5 % . f o r the first order leaching rate constant k =chromium from 4 - 36%. average 17%. r/CCAtot (hr-‘) were calculated for Cu, Crfor arsenic from 7 - 68%. average 34% and As from the experiment I. Results are(Table 3). From Fig. 12, it appears that the given in Table 4. Copper, chromium andleaching of CCA proceeds at an almost con- arsenic leaching for the different pipes can bestant rate. This may be explained by assum- best compared by looking at the first ordering that leaching is a first order process, which leaching rate constants, because in k differ-

Table 3. Retention (as gr metal ion per kg bamboo) and Leaching (as % of retention) ofcopper (Cu), chromium (Cr) and arsenic (As) from 2 cm bamboo rings.

B a m b o o Copper C h r o m i u mring - r e t . leac. re t . leac.

1 0.89 23% 2.04 24%2 1.35 14% 2.60 1 9 %3 1.20 13% 1.95 1 5 %4 1.09 24% 3.67 2 0 %5 0.92 28% 2.32 30%6 A 3.12 5% 2.46 21%B 2.37 13% 2.51 1 1 %7 A 5.84 9% 5.55 1 8 %

B 4.32 10% 4.05 2 2 %8A 1.06 12% 2.82 4 %

B 4.20 14% 3.47 5 %

* = A indicates that samples were taken 50 100 cm from butt-treatment-endI3 250 - 300 cm from butt-treatment-end.

Arsen icre t . leac.

0.70 4 6 %0.97 4 1 %0.77 41%0.92 2 4 %0.95 5 5 %1.21 4 2 %1.30 3 0 %2.66 3 3 %1.72 4 3 %2.05 1 1 %1.81 1 4 %

333

Table 4. Leaching rates (r = mg metal ion per kg bamboo per hour) and first orderleaching rate constants (k = 10-4 hr-1) for copper (Cu), chromium (Cr) and arsenic (As)

in a number of bamboos,

Bamboo Copper Chromium Arsenicr k r k r k

1 0.30 2.5 0.78 2.5 0.25 2.5

0 . 2 8 ’ 0 . 1 1 2.3 1.2 0 . 9 0 0 . 4 1 4.2 2.1 0 . 6 7 0 . 3 4 6.8 4.34 0.21 2.1 0.73 1.7 0.17 2.05 0.47 4.9 0.95 4.8 0.58 6.26 A ’ 0.28 2.5 0.61 7.8 0.84 15.1

B 0.14 1 . 0 0.27 1.8 0.42 4.57 A 0.36 2.6 0.83 3.5 1.10 6.1

B 0.71 5.4 1.60 1 0 . 0 1.70 13.28 A 0.06 0.5 0.20 1.0 0.26 1.6

B 0.18 1.0 0.31 2.5 0.45 4.6

average 0.28 2.4 0.69 3.8 0.62 6.1

"! A 50= - 100 cm fmm the butt-treatment-end.B = 250 - 300 cm from the butt-treatment-end.

ences in loading of CCA are levelled out.From the data it is clear that copper leachedless and arsenic most as a percentage of total

retention. However because of the higher rvalues, chromium will contaminate the watermore. There is a positive correlation betweenchromium and arsenic leaching.

All experiments show that when thesepipes are used for transportation of drinkingwater. high concentrations of Cu. Cr and Ascan be expected in the water. A 2 m long CCAtreated bamboo pipe was washed in the riverfor one month. After this washing time it wasconnected to the circulation installation(experiment III) and water was pumpedthrough it for ten hours representing 500 m ofpipeline. The next concentrations of Cu, Crand As were measured:

500 m bamboo pipe Cu = 0.2 mg/lCr = 0 .2 mg/lA s = 0.3 mg/l

Tanzanian standard Cu = 3 mg/lallowed in Cr = 0 .05 mg/ldrinking water A s = 0.05 mg/l

These results do not need further elaboration.

Although the experiment II shows thatleaching may terminate in time, extensivewashing procedures on a large scale are notrecommended because of high environ-mental pollution. It should even be ques-

tioned if the salt retained after extensive wash-ing is sufficient for protection. The amount ofsalt retained was determined in a pipe installedas test pipe three years ago, and found to bedown to 3.4 kg. Leaching and fixation wereinvestigated for different procedures of Bou-cherie impregnation (first flushing with water- sap removal - or acid, following the resultsof bamboo sawdust impregnation). However,possible effects were masked by the very irre-gular leaching patterns of normally 5% CCAtreated bamboo.

In the Bamboo Project, the resultsobtained with CCA - Boucherie impregna-tion of bamboo pipes were disappointing,High leaching rates of the toxic compoundsmake the use of a CCA - Boucherie treatedbamboo pipe as water conduit impossible.This result is in marked contrast to the resultsobtained with CCA bamboo sawdust impreg-nation. For this system, good fixation could bereached when sufficiently high concentrationswere used. Selective adsorption and diffusionof the different metal ions during and after theBoucherie process and invalidates the modelas presented for the CCA - bamboo saw-dust system. Experiments for CCA -bamboo sawdust impregnation revealed thata high instantaneous loading of CCA is neces-

sary for good fixation (more than 50 g CCAper kg bamboo). This condition will be real-ized in the vessels, when we look to the

3 3 4

amount of CCA in direct contact with thebamboo tissue. This is confirmed by the mea-surement of the pH of the effluent preserva-tive. Immediately after starting the treatment,the pH of the collected sap reached 5.16 (then a t u r a l pH o f t h e Arundinaria alpinabamboo). During the course of the treatment,the pH dropped to + 3.5. However, the CCAin the vascular bundles was hardly exposed tothe reactive groups of the bamboo tissue andthis low pH would not result in good chromiumreduction (as in the sawdust system). Fixationof CCA is merely the result of the formationof precipitates within the sap vessels and evenfor this the situation is not optimal (low pH).Investigations of CCA - Boucherie treatedbamboo pipes buried for three years in thesoil as test pipes revealed that the bamboowas still sound, although slight nibbles of ter-mite attack could be seen on the outside. Thecontrol pipes were totally destroyed by ter-mites and rot. The total salt retained haddropped considerably due to the severeleaching’ conditions. All experiments indicatethat CCA - Boucherie treated bamboo willbe well protected against termite attack androt for a long time when not exposed tosevere leaching conditions. By using differenttechniques of impregnation, it is possible thatsufficiently high fixation can be reached. Alltechniques depend on diffusion of the’ metalions and therefore resemble closely the Bou-cherie impregnation. Experiments carried outwith pressure impregnation gave an averageleaching of arsenic of 44%.

AcknowledgementsThe results presented here are the data of

a joint-research programme of the BambooProject in Tanzania and the water chemistrygroup of the Delft University of Technology.the Netherlands. The research was financedby the Netherland Ministry for DevelopmentCooperation (hard currency component) andthe Tanzanian Ministry of Water (under whichthe Bamboo Project falls). The bulk of thechemical analyses were performed at theDelft laboratory by J. Donker. Mr de Leer(initially P. Schreur) supervised this work inhis function as head of department. Mr Slob(a chemist) was employed through SNV(Netherland organization for DevelopmentAssistance) as a scientific coordinator of the

research program in Tanzania. He wasassisted by Mr Nangawe, a Tanzanian forestofficer with a long standing experience inwood preservation. They conducted the fieldexperiments, while laboratory facilities wereput at their disposal by Dr Madati, Head ofthe Government Chemist Laboratory, Dar esSalaam. Here Mr Siafu assisted in the chem-ical analyses.

References

Arsenault, R.D. 1975. CCA treated woodfoundations, a study of performance,effectiveness, durability and environ-mental considerations. 126-149. In:Conference of the American Wood Pre-servers Association.

Bleyendaal, H.P.O. 1978. Protection ofwood and bamboo in the tropics. PaperNo. 4, Department of Forestry, Univer-sity of Agriculture, Wageningen, theNetherlands.

Dahlgren, S.E. and Hartford, W.H. 1972.Kinetics and mechanism of fixation ofCu-Cr-As wood preservatives. Part I. pHbehaviour and general aspects on fixa-tion. Holzforschung 26: 62-69.

Dahlgren, S.E. and Hartford, W.H. 1972.Part II. Fixation of Boliden K33. Holz-forschung 26: 105-l 13.

Dahlgren, S.E. and Hartford, W.H. 1972.Part III, Fixation of Tanalith C and com-parison of different preservatives, Holz-forschung 26: 142-149.

Dahlgren, S.E. and Hartford, W.H. 1974.Part IV. Conversion reactions duringstorage. Holzforschung 28: 58.

Dahlgren, S.E. and Hartford, W.H. 1975.Part V. Effect of wood species and pre-servative composition on the leachingduring storage. Holzforschung 29: 84.

Dahlgren, S.E. 1975. Fixation of Cu-Gr-Asbased wood preservatives, The SwedishWood Preservation Institute. Report 113.Stockholm.

Dunbar, J. 1962. The fixation of waterbornpreservatives in cooling tower timber. 25-39. In: Proceedings of 12th Annual Con-ference of the British Wood PreserversAssociation.

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Evans, F.G. 1978. The leaching of copper,chromium and arsenic from CCAimpregnated poles stored for ten years inrunning water. 10th Annual Meeting ofthe International Research Group/WoodPreservation. Document IRG/WP 3122.Peebles, Scotland.

Henshaw, B. 1978. Fixation of copper,chromium and arsenic in softwoods andhardwoods. Princess Risborough Labora-WA Buckinghamshire, England.Document P.D. 152/78 P.R. 30/024.

Heuvel, K. van den. 1981. Wood and bam-boo for rural water supply - a Tanzanianinitiative for self-reliance. Delft UniversityPress, the Netherlands.

Higuchi, T. and Kawamura, I. 1966. Occur-rence of p-hydroxyphenyl-glycerol B-arylether structures in lignins. Holzforschung20: 16-21.

Liese, W. 1980, Preservation of bamboos:In:Proceedings of the workshop on BambooResearch in Asia. International Develop-ment Research Centre and InternationalUnion of Forestry Research, Singapore.

Lipangile, T.N. 1985. Bamboo water pipes.Waterlines 3. London.

Msimbe, L. 1985. Wooden and bamboomaterials in the implementation of waterfor all Tanzanians by 1991. WEDC 1 lthConference on Water and Sanitation inAfrica. Dar es Salaam Tanzania.

Nakatsubo, F., Tanahashi, M. and Higuchi,T. 1972. Acidolysis olf bamboo lignin,part 2 isolation and identification o facidolysis products. Wood Research 53:9-18.

Pizzi, A. 1981. The chemistry and kinetic be-haviour of Cu-Cr-As/B wood preserva-tives. Part I. Fixation of chromium onwood. Holzforschung und Holzverwer-tung 33: 87- 100.

Pizzi, A. 1982. Part II. Fixation of the Cu/Crsystem on wood. Journal of PolymerScience, Polymer Chemistry Edition 20:707-724.

Pizzi, A. 1982. Part III. Fixation of the Cr/Assystem on wood. Journal of PolymerScience, Polymer Chemistry Edition 20:725-738.

Pizzi, A. 1982. Part IV. Fixation of CCA towood .l Journal of Polymer Science,Polymer Chemistry Edition 20: 739-764.

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336

Bamboo Plywood - A New Product ofStructural Material with High

Strength PropertiesChen Guisheng

Project Leader, Bamboo Plywood Research Group and Director of Forest ProductsLaboratory, Nanjing Forestry University, Nanjing, China.

AbstractThe paper describes the procedures

involued in making bamboo plywood. It thend i scusses the comparative merit of theproduct.

Bamboo plywood is a panel consisting ofan assembly of plies of bamboo sheetsbonded together with the direction of thegrain, in alternate plies at right angles. Anadhesive of phenolic resin is used. The bam-boo species used for the raw material is Phyl-lostachys pubescens (Mazd) which averages9 cm in diameter at the breast height.

The processing procedure is as follows:

Bamboo culm is first crosscut into four orso with the desired lengths and the inner andouter surface layers are scraped out on equip-ment specially designed. The cuts are thensplit open into two or three pieces. Followinga pretreatment by soaking the pieces in acooking vat for several hours, the pieces aredipped in a vessel with a medium at a tem-perature far beyond 100°C so as to enhancethe temperature of the pieces to a certaindegree to soften the wood. This serves tothermoplasticize the Iignin and hemicellu-lose more effectively. The treated pieces arethen spread out, flattened, dried and stabilizedthrough a heated press and a breathing drier,specially used for processing bamboo sheets.The pieces are planed smooth and edgedstraight on both sides. This prepares, thematerial - faces, backs and crossbands - forthe manufacturing of bamboo plywood. Theforthcoming procedures are just the same asthe manufacture of plywood. Bamboo ply-wood is extremely high in bending strength -modulus of rupture (MOR); modulus of elas-ticity (MOE) and it probably ranks as thehighest among all of the structural boards andeven as good as the solid wood of highdensity commercial timbers. Bamboo coupledwith wood is a material of heterogeneity and

anisotropy. This property may be evaluatedas a disadvantage on the one hand and anadvantage on the-other. Some may place thisproperty of bamboo at a disadvantage incompetition with other products. In fact,many of the disadvantages, real or implied, asdecay and insect attack, could be overcomeby intelligent use of bamboo, based on a com-prehensive knowledge of its characteristics.

It is known that bamboo is exceptionallyanisotropic in nature and this character couldbe overcome by crossbanding to a certainextent as desired. The problem is in devel-oping the resulting characteristics to a muchhigher degree as we do in oriented strandboard (OSB) and also in oriented strand com-posite plywood (OSCP). Bamboo plywoodserves this purpose. As the orientation offibers in bamboo is nearly perfect along thegrain, the bending strength of the product isremarkably superior to those of OSB andOSCP. It is also high in flexible rigidity. Incomparison with other structural materialsother than wood and wood products, theyare mostly isotropic and there is no way tostrengthen the bending strength and stiffnessas expected.

A tentative comparison of strength pro-perties of a few structural materials is shownin Table 1.

We understand that the nature of the cellwall substance and its distribution as a systemof thin-walled tubes makes wood very effi-cient in flexible rigidity. So does bamboo. Thishigh flexible rigidity is most effective in mem-bers as beams in which length is far in excessof depth. In comparison with other structuralmaterials, the weight - strength ratio forbamboo product is very favorable for someapplications. This high stiffness - to -weight ratio exhibits a characteristic which isconsidered to be an important criterion forevaluating the mechanical properties of a

337

Table 1. Comparison of five wood based materials.

Material S t rengthMOR (Kg/cm2)

Part icleboard (random) 2 3 5

OSCP 740

Bamboo Plywood 1,175

Oak, Chinese species 1,506

Oak, American species 1,655

Proper t iesMOE (Kg/cm2)

,34,483

42,200

211,000

149,000

163,448

.

material and this form of cellular organizationis also a highly efficient means for obtainingthe maximum moment of inertia from aminimum amount of material. The momentof inertia of a bending member is vastlyincreased if a given amount of material isarranged as a tubular structure rather than asolid rod. For this reason, bamboo productshave a high index of rigidity in comparisonwith solid structural materials and is wellsuited for use in situations that require elasticstability. Compared with wood, bamboo pro-duct is at least nine times as good an energy-absorbing medium as steel. This makes it anexcellent material for floors and similar appli-cations where energy absorption is important.

Bamboo, being similar to wood, is a cel-lular substance and in the dry state the cellcavities are filled with air, which is one of thepoorest conductors known. Because of thisfibrous structure and the entrapped air, bam-boo has an excellent insulating property. Thecommon building materials used in houseconstruction with the exception of wood arenot good insulators. In comparison withwood, the heat loss through common brick issix times and through a glass window eighttimes as great, whereas concrete and steel arefifteen and three hundred ninety times as con-ductive as wood respectively. Experimentsshow that the coefficient of heat conductivityof bamboo product is a little higher than thatof wood, but the difference is too small to betaken into account.

Bamboo plywood associated with woodand wood products provides thermal insula-tion the year round. It is effective not only inwinter against cold, but also in the summeragainst heat. Combined with wood, it is aremarkable structural material for shelterwhere an effective thermal insulating propertyis necessary.

Wood structures can withstand an impactload twice as great as that of static loading. Itis also true for bamboo products. This excep-tional impact strength gives it a considerablemechanical and economic advantage forstructures designed to resist earthquakes orfor si tuations where abrupt loads areimposed. Bamboo is susceptible to fungi andinsect. Experiments demonstrate that nodamage of decay and insect attack hasoccurred, when phenolic resin is used as thebinder of the bamboo plywood. This is alsothe case in fire resistance. There is no reasonwhy, if properly used, bamboo productsshould not last indefinitely. Because of theshortage and uneven distribution of forestresources in China, the supply of timber is farbelow the ever-increasing demands of thecountry. Therefore China’s scientists exploreall possibilities to use wood efficiently anddevelop new product replacement for it. Themanufacture of bamboo plywood is perhapsone such achievement in this field.

China is lucky in having extensive bam-boo resources with more than 300 species.There are 3,401,800 ha of bamboo stands ofwhich 2,418,600 ha is made up of Phyl-lostachys pubescens. The growing stock isa b o u t 3,759,890,000 ( 3 . 7 9 6 t h o u s a n dmillion) bamboo culms. On a hypotheticalrotation of six years, the annual harvestingwill be about 632,648,300 culms. Anestimate on the number of culms of bambooof 9 cm diameter needed for making 1 m3 ofbamboo plywood has been made on a pilotplant. The results show that 150 culms wouldbe sufficient to meet the need at the presentrunning level. This means a total of4,217,650 m3 of bamboo plywood which isequivalent to four times the present produc-tion of all the wood-based materials, could bemade annually.

3 3 8

A Brief Introduction to the Bamboo Towerin Zurich, Switzerland

Li Qihuang, Li Dezhao, Song Changkun

Kunming Architectural Design Institute, China.

AbstractThe details of a bamboo tower construc-

tion undertaken in Switzerland are described.

Introduction

Based on the sketch by Mr Peter Staub, awell-known plastic artist, a bamboo tower wasset up as one of the exhibits in the“phenomena” Exhibition held in Zurich,Switzerland in 1984, and it really provided arare opportunity in displaying the gracefulbearing of a bamboo building. The tower wassuccessfully completed through a joint effortby the Kunming Architectural Design Instituteand the Kunming Construction Company.Facts proved that the sponsors of the Exhibi-tion had actually made a wise decision withforesight and sagacity. The building addedIustre to the Exhibition and was widelyacclaimed. It was later reconstructed inRotterdam, Holland in the middle of 1985.With the maximum height of 22.50 m, it wasdivided into five floors, from bottom up eachwith 5.40, 4.05, 4.05, 6.0 and 3.0 metershigh respectively. Furthermore, one largespiral slide with 19.50 m in height, 60 m inslope length and three small slides with 5.4 min height were also provided. Since thebuilding of this kind had hardly been seen, itattracted a good deal of attention and interestfrom the architectural circle and bambooresearchers.

General Considerations ofDesign

An equilateral triangle 2.40 m length foreach side was taken as a basic plan unit. 49honeycomb spaces were made up by meansof a separation of floors, which had advan-tages of stable plain and fewer members inkind. In addition, the architectural appear-ance was very obvious. All these made the

configuration of the building varied andco1ourful.

Details of Technical Treatment

The combined pillars were made up of 3-6 pieces of bamboo and bundled up at everymeter by at least 10 strands of bamboo stringsat each point. The lower end of the pillar wasconnected to its foundation through a steelplate. A timber was provided on the horizon-tal bamboo pole under the floor to form thecombined upper chord of bamboo-woodwhich dispersed loads and reduced bendingstresses as well as helped fix wood boards.The tongue and groove boards were arrangedalong the different directions to make thefloor more even.

The following joints were used. i) the buttjoint with wood/bamboo core plus bamboopins, ii) the bake-bent joint, iii) the shearjoint with a bracing piece, iv) the tenon jointwith or without wood core, v) the screw jointwith holding boards (used for central joint inthree hinged arches), and vi) the joint withscooping-out plus bamboo pins. In the regularhexagon plain unit, spiral stairs weredesigned. The radial foot rest passed throughthe straight vertical pillars outside and centraltubes were decorated with bamboo slips.Through ingenious arrangement of thebamboo poles, the entire stair hall was wellrevealed giving an appearance of the bamboostructure.

The following measures were taken pre-venting the bamboo from rot, crack anddecay. i) The bamboo was cut over in thelate autumn or early winter, ii) Insecticideswas sprayed on ends of the bamboo. iii) Thebamboo was strengthened by means of fire-baking and was cleared of any greasy dirt.This also brought the natural colour and lustreof the bamboo surface, iv) Bamboo stringsare used in important sections to prevent thebamboo from cracking. v) Good care wastaken of the bamboo material during

339

transportation and storage to avoid deformityand damage.

Main Points in the constructionof the tower

The project involved all together 6,000pieces of bamboo with over 100 mm indiameter, and 5,000 pieces of other kindsand dimensions. With a net weight of 120tons all of the required bamboos was pur-

chased and shipped to Zurich The selectedbamboos were more than 4 years’ old,straight and free of rot, The bamboo used wasstraightened and surface treatment carried.out prior to processing. The frames on pro-cessing were numbered, classified andpacked in containers,

The large bamboo tower in Zurich wasattractive and contructed by joining.

Mr Yang Benkuan and Mr Tian Jianongof our Institute, also participated in construct-ing the Bamboo tower.

340

A Study on Bamboo Cellulose Triacetate(B-CTA) Ultrafiltration Membranes

Liu Yu-Rong, Chen Yi-Ming, Lang Kang-Min and Bao Zhi-Guo

The Development Centre of Seawater Desalinationand Water Treatment Technology

National Bureau of Oceanography Hangzhou, China.

Abstract

The methods for making B-CTA and C-CTA (cottqn-cellulose triacetate) ultrafiltrationmembranes and the factors a f fect ing themembrane properties are described here. Thestorage of the membranes in 95% ethanoland aqueous solution is mentioned.The results for trial of the membranes in phar-maceutical and food processes are alsoreported.

Introduction

Ultrafiltration (UF) is a new technique ofmembrane separation .- The filtration processinvolves sieving effect and chemical behav-iour of the substance on the surface of themembrane. Solvents and materials with lowmolecular weight pass through the membraneunder a given pressure, and suspendedmatters and macromolecules are rejected,therefore the filtration, separation or purifica-tion of liquids treated are obtained. UF tech-niques were used only in laboratories before1960. Various types of ultrafilters have beensubsequently manufactured with the success-ful development of the UF membranes. UF hasbecome an independent unit operation inchemical engineering. Widely used in food,chemical and pharmaceutical industriesabroad. The applications of UF were tested intreatment of eiectrophoretic paints, purifica-tion of dyeing waste, separation and concen-tration of biological products and clarificationof beverages in our country. Some of thesetests have been applied in corresponding pro-ductions. It is important to choose and usemembrane materials correctly with propermembrane-making technology according to

the requirement of production and industry. Itwas more than 20 years since Loeb andSourirajan successfully developed asym-metric CA membranes. Although other mem-brane materials have been widely studied bymany membrane scientists during this period,to date CA is still the main membrane materialat home and abroad, The main reasons for thisare as follows: Compared with other mem-brane materials, the resource of raw materialfor CA is easily available and the price is cheap.The technology for making CA membranes issimple, and the membranes have good sepa-ration properties, are resistant to chlorine andnon-toxic. However there are a few limita-tions for the applications. In order to expandthe range of applications of CTA membranes,and to utilize the abundant bambooresources, fully B-CTA ultrafiltration mem-branes with different pore size were made bythe industrial Bureau of Suichang county,Zhejang Province.

Preparation Of Filters

1. Components of cast solution: Cotton-velvet CTA, B-CTA, acetone, Dioxane,methaiene dichloride, formamide, ethanoland water.

2. Preparation of cast solution: The CTA wasdried in the oven at 105°C for about 1 hour,and the temperature droped to ambient. TheCTA, solvents and additives were added inproper proportion into a glass flask withan agitator. The mixture in the flask wasagitated for dissolution, then filtered and stilledto make it bubble free.

3. Preparation of membranes: The room forpreparation of membranes was air-condi-

342

tioned and humidity-controfled. The cast solu-tion was decanted into the slot of casting knifemounted on the casting machine, and thecasting machine was allowed to run. The castsolution passed through the casting knife, andwas spread into thin layers of solution undercontrolled solvent evaporation. After gelationin water bath, the wet UF membranes wereformed. The dry UF membranes could bemade when the wet membranes were treatedwith post-treatment agents.

4. Measurement of the membrane proper-ties: The dry UF membranes were cut intoproper size and shape, and mounted intoultrafilters. The water flux and cut-off of mole-cular weight were measured under givenpressure, using distilled water and differ-ent protein solutions as feed respectively.

the membrane-making conditions on the pro-perties of the membranes. These are sum-marized as follows:

1. Effects of contents of B-CTA and C-CTAin cast solution on properties of the mem-branes: For the last 20 years, asymmetric C-CTA membranes have been made in our labo-ratory but we do not have any knowledge ofmaking B-CTA membrane. Through a seriesof experiments, it was found that B-CTA84038 was suitable for making membranes. Atthe beginning, we prepared the B-CTA ultrafil-tration membrane using the recipe for makingC-CTA membrane.

Results and Discussion

The structure of the membrane as seenunder electron microscope is shown in Fig. 1.The flux was low and the cut-off of molecularweight was also poor for these UF mem-branes. Therefore further experiments weremade to determine proper composition ofcast solution. The results are summarized inTable 1.

Membranes with good rejection and high The properties of the UF membranes forflux are essential for the application of UF. the two kind of CTA were basically similar

The composition of cast solutions and the pro- after dozens of sifting test, and their micro-

cessing conditions in making the membranes structures were also similar (Fig, 2).

are decisive factors for preparing UF 2. Effect of additive contents on the mem-membranes with good properties. We have brane properties: The results are summarizedmade a comparison on the properties as shown in Table 1. Both kinds of additivesbetween the B-CTA and C-CTA membranes, and the different amounts of the same additiveand a systematic investigation of the effects of have a great influence on the dissolvable state

Table 1. Effect of contents of B-CTA and C-CTA in cast solutionon the membrane properties.

B-CTA 84038 C-CTA 82855(Wt%) (Wt%)

5 5 490

6 4 462

7 3 442

8 2 438

9 1 414

10 0

0 10

Temperature of feed water

(°C) 10

Measurement apparatus: Ultrafilter with effective membrane area 10 cm2

Measurement condi t ions : Opera t ing pressure 3 kg/cm2. feed tap water.

F lux(ml/cm2 hr)

760

692

708

668

448

708

738

14

472

644

580

512

452

710

716

10

343

Fig. 1. Electron rnicrograph of B-CTA ultrafiltrationmembrane (3000 x 1

of cast solution. It is therefore very importantto choose a proper additive as a pore-formingagent in making UF membrane with excellentproperties. It was found that the mixture offormaldehyde and ethanol was a suitable addi-tive for B-CTA after a lot of times in sifting theadditive. The effect of the additive contents onthe membrane properties is shown in Table 2,

It can be seen from Table 2 that water fluxwas increased with the increase of additivecontent. When the ratio of the additive in castsolution was more than 70dissolve the polymer, Va

Table 2. Effect of additive contents on the membrane properties,

itwe content

Additive content

344

with different water flux can be m a d e tosatisfy the requirements of cor respondingapplications.

3. Effects of membrane-making conditionson the properties of membranes: There weremany great differences in properties of themembranes which were prepared from thesame cast solut ion, hut under differentmembrane-making conditions. More densemembranes with lower flux were formedunder certain conditions, but the membranewith high flux and large pore size could beobtained by changing some of theseconditions. The microstructures of the twokind of membranes are shown in Fig, 3,

( i ) E f f e c t o f gelation temperature onmembrane properties* The more importantstep for preparation of UF membrane fromcast solution is to dip the just-cast membraneinto water ~ the elation me d i u m Theexchange rate between water, solvent andadditive is faster in water with high tempora-tures than at low. The pore size and water fluxof the membrane obtained from the bath athigh temperatures are higher than those fromthe bath at low temperatures The expcen-mental results are listed in Table 3.

As may be seen from Table 3, theexchange rate between water, solvent andadditives increased with the increase of tem-perature. The flux reached maximum atthe gelation temperature of about 30° The

membranes became denser and their fluxwere also low when the gelation tem-perature was higher than 30°C, this micaused by the change of gelation mecha

(ii) Effects of increasing temperature and timeon the membrane properties: The UF mem-branes need to be sterilized at high tempera-ture when they are used for purification andseparation in pharmaceutical and food pro-cesses. Thus the membranes were put intohot water at differentcertain period to test theperties, The results are s5.

3 4 5

Table 4. Effect of increasing temperature on the membrane properties.

Annealing temperature 30 40 50 60 70 80 90 loo(°C)

Water f lux(ml/cm2 hr)

8 4 0 824 680 672 592 580

Water flux(ml/cm2 hr) 956 912 686 786 762 568 540 512

!" The annealing period: 30 min.

Table 5. Effect of annealing on the membrane properties !

Annealing period (hr)

Water flux(ml/cm2 hr)

!" The annealing temperature; 1OO°C.

0.5 1.0 2.0

540 386 342

It was obvious that the flux of the mem-brane decreased with the increase of annealingtemperature. Because annealing is a processof “dehydration and shrinkage” of the mem-brane. UF membranes with different pro-perties (flux, pore size and surface structure)could be prepared by adjusting annealingtemperature.

The flux of the membranes decreased andthe strength of membranes increased withextension of annealing period, indicating con-traction of the pore sizes in the membranes.The flux of the membrane was still acceptableafter annealing of the membrane at lOO°C for2 hours.

(iii) Effects of the concentration of plasticizerand drying temperature on the membraneproperties: Dry membranes are convenientfor storage, transportation and operations inthe manufacture of modules, and bacteria wasalso eliminated in the dry membranes. Themembranes dried naturally at ambient condi-tion were brittle and poor in strength. Thereason for this might be the large surfacetension between water and the wall of pore inthe membrane: and crevices were thencreated at the wall of the pore after water

evaporated from these pores. If the actionbetween water and CTA is decreased bylowering the surface tension between them,

Table 6. Effect of plasticizer concentration on the membrane properties.

Plasticizer concentration 0 10 15 20 25 30 35(Wt%)

Water f lux 768 936 748 736 624 580 868(ml/cm2 hr) 852 702 630 570 668 812 652

676 472 560 744 1075’ 548 612644 368 528 723 1023 ! 516 524

apperance of dry and white, Flexibility of the membrane is increased with thethe membrane brittle and breakable increase of glycerol concentration. Usually 15-20%

glycerol was chosen for drying membrane.

!" Temperature of feed water: 78°C. other temperature: 12°C.

346

the loss of water in the membranes does the properties of B-CTA ultrafiltration mem-not cause the cracks on the pore wall. We brane after storing them for more than 3tested a few surfactants and plasticizers, months under the above conditions.

as it is non-toxic and suitable for food andpharmaceutical processes. Table 6 shows theeffect of concentration of plasticizer on theproperties of membrane.

and finally glycerol was chosen as plasticizer,

The drying of the membranes was faster athigh temperature’s than at low. Effect of dryingtemperature on the membrane properties wastested in order to find a proper combinationbetween drying temperature and period forcasting membrane continuously by machine.The results are given in Table 7.

It can be seen from Table 7 that dryingtemperature only had a slight influence on theproperties of the membrane. Drying tempera-ture at 60-70°C was chosen for convenientoperation, and the membrane could be driedin 5-10 minutes at this range of temperature.

(iv) Storage experiment: In order to satisfy therequirements in food and pharmaceuticalindustries, the membranes were dipped into95% ethanol and medical aqueoussolution for a certain period to see the changeof membrane properties. The results areshown in Table 8.

Table 8 shows that there was no change in

(v) Effect of feed temperature on the mem-brane properties: UF membranes have highflux. The operating conditions, such as feedtemperature, etc, have a great influence onthe membrane properties. The effect of feedtemperature on membrane flux was testedwith tap water as feed. The results are given,in Table 9.

As shown in Table 9, the flux increasedwith the increase of feed temperature. This isbecause the viscosity of water at high tem-perature is smaller than that at low tempera-ture, and the resistance to water passingthrough the membrane also shows the sametrend.

4. Trial of B-CTA ultrafiltration membrane infood and pharmaceutical processes: There areno phase change and thermal effect in UFprocess and therefore UF process plays a veryimportant role in food and pharmaceuticalindustries. For example, in UF of beverages,the impurities are removed, bacteria elimi-nated and the colour, flavour and nutrients ofthe beverage are preserved, making thebeverage more tasty. The preliminary resultson UF of wines are shown in Table 10.

Table 7. Effect of drying temperature on the membrane properties.

Drying temperature 9 30 40 50 60 70 80 110 126 142(°C)

Water flux 248 452 384 400 393 450 462 - - -

(ml/cm2 hr) 476 363 - - - 360 336 336 318 544

Table 8. Effect of storage on membrane properties under different conditions*

Date of measurement

Flux of membrane stored in 95% ethanol(ml/cm2 hr)

April 15, May 6, July 18.1985 1985 1985

226 224 216

Flux of membrane stored in medical aqueous so lu t ion (ml/cm2 hr)

219 218 210

Flux of dried membrane (ml/cm2 hr)

"! The flux of wet membrane: 248 ml/cm2 hrmeasurement conditions are the same as in Table 1.

248 - 250

347

Table 9. Effect of feed temperature on the membrane properties.

F e e d temperature (°C) 7 15 30 50 78

Water f lux(ml/cm2 hr)

339 447 672 1278 1872

Table 10. Ultrafiltration of wines.

n a m e

beforeUF

afterU F

corn a lcohol

There are flakedcoagulan ts a t 50°

Clear bright

sorghum wine

Flaked coagulantsand b lackprec ip i tan t s p resen t

Clear t ransparenttasty

hangzhou Xiangqu

Grey and black Milky white andprecipitants grey particles

clear t ransparent tasty notasty particles

In addition, UF was used in glucose infu-sion and the maximum of finished product wasraised from original 85%) to 99%. Accordingto the results reported elsewhere, UF wassuccessfully used in food, pharmaceutical,chemical engineering and electronic indus-tries. UF will also be widely used in the pro-duction of ultrapure water, separation inchemical engineering, pharmaceutical andfood, industries in our country.

Conclusion

the properties of C-CTA and B-CTA ultrafil-tration membranes.

The properties of B-CTA ultrafiltrationmembrane are similar to that of C-CTA.

B-CTA with degree of polymerization 300can easily be dissolved, but the conditions formaking membranes are more severe.

Cast solution of B-CTA is clear and trans-parent. B-CTA is slightly better than C-CTAin resistance to acids and alkali. so the rangeof application f o r B - C T A ultrafiltrationmembrane is wider than that of C-CTA.

Experiments were carried out to compare

348

Traditional Preservation of Bamboo in Java,Indonesia

Achmad Sulthoni

Faculty of Forestry, Gadjah Mada UniversityYogyakartu, Indonesia

Abstract

The traditional method of bamboo preser-uation by immersion in water, followed by therural Javanese is adequate. The immersionfor a month decreases the starch content of thetreated bamboos and provides considerableresistance against the powder post beetle,Dinoderus minutus and D. brevis . TheJavanese felling season “mangsa” XI helpsto prevent damage by beetles. Traditionalpreservat ion of Dendrocalamus asperindicates an improvement in the resistance.On Gigantochloa apus and G. atter theeffect is insignificant, but these two bamboospecies have the least starch contents andhighest degree of resistance. The immersiontreatment does not work sufficiently for Bam-busa vulgaris due to its high content ofstarch. The treated bamboos indicate a consi-derably better performance at Ieast for oneyear.

Introduction

Bamboo is an important, cheap, andplentiful resources in Indonesia. It could befound almost everywhere, mostly in theislands of Java and South Sulawesi, consist-ing of more than 30 species, distributed geo-graphically up to 2000 m above sea level(Hildebrand, 1954). A survey conducted inthe Province of Yogyakarta on 30 “kecama-tan” indicated that bamboos grow every-where, planted by the rural communities(Haryono Danusastro et al., 19’79; 1980;1981). It has been observed that 13 species ofbamboo are grown by rural people in theirhomeyards; four of which have been most

3 4 9

extensively used, especially for constructionpurposes, i.e., Gigantochloa apus Kurz, G .atter ( H a s s k . ) Kurz e x M u n r o , Dendro-calamus asper Back., and Bambusa s p .(Abdurachim, 1967; Hildebrand, 1954;Heyne, 1950; Widjaya, 1980). Utilization ofbamboos for construction is about 13% in therural areas of the provinces of Yogyakarta,Central Java, East Java, and Bali; its roleincreasing to 30% for residential building con-struction; it is used for roofing, partitionwall, and ceiling frames (Anon., 1977; Anon.,1982) .

Bamboo is more susceptible to biodeteri-orating agents as compared to timber, such asfungi, termite, and especially insect borers(Liese, 1980). Among the insect borersobserved in his study, Sulthoni (1981;1983a) considered powder post beetles Dino-derus minutus Fab. and D. brevis Horn. themost damaging.

Untreated bamboos used in open placesand on ground are generally destroyed inabout one or two years (Varmah and Pant,1981). Treatment of bamboos with preserva-tives is widely regarded as necessary, buthowever it is seldom carried out; the reasonsare a lack of knowledge about possibleuse of chemical preservatives, the uncer-tainty about the advantage of bamboo preser-vation, and the lack of market for treatedbamboos (Liese, 1980).

Preservation Of Bamboo

Two methods of preservation could bedone either chemically or non-chemically.Chemical treatment of bamboo using preser-vatives could be applied on dry or green orfresh bamboos, and some techniques for

preservation are the following (Tewari andBidhi Singh, 1979) :

1. Washing and coating: A variety ofcoatings such as tar, lime wash, tar and limewash, and tar sprinkled with sand are used inIndonesia by house builders. These coatingsare successful only when continuously doneon cut surfaces, exposed internodes, abra-sions and splits.

2. Brushing, swabbing, spraytng anddippling: These surface treatments are fortemporary protection of bamboo in storage orbefore it is given impregnation treatments.Various chemicals used are aqueous emul-sion of insectisides like dieldrin 0.03%, aldrin0.015%, or D.D.T. 7-10% in kerosene oil. InJapan, mercury and tin salts have also beenused for protection against borers and fungirespectively. Other chemicals such as sodiumpentachlorophenate, borax and boric acid arealso used.

3. Soaking: Air-dried bamboos haveonly to be submerged in the preservative solu-tion (oil or oil solvent type) for a perioddepending upon the species, age, thicknessand absorption required. The penetration ispredominantly by capillarity. The soakingmethod requires little equipment and tech-nical knowledge, provided the schedule oftreatment, such as type of preservatives, theirconcentration and the period of dipping, i sworked out. The absorption of preservative ismore in half round specimens in comparisonto round ones.

4. Boucherie process: In normal Bou-cherie process the Bamboo is treated by pre-servative through gravity from a con-tainer placed at a height. In India this methodwas modified later on by using a simple handpump. By means of air pressure of 1.0 to 1.4kg/cm2 applied to the preservative container,the preservative is pushed through the tissuesof the green bamboo. This modified proce-dure reduces the period of treatment signifi-cantly and under the pressure the treatingsolution forces the sap out of the walls andsepta of the bamboo through the open endand replaces it in course of time.

The penetration and absorption of thepreservative depend upon several factors,such as concentration, treatment time, natureof chemical used, age and dimension of thebamboo, moisture content, etc.

5. Steeping method: This method gen-erally consists of allowing freshly cut culms,with the crown and branches intact, to standin a container holding the preservative solu-tion to a depth of 30 to 60 cm. Through leaftranspiration current, the solution is drawn upto the stem. The period of treatment dependsupon the species, the length of the culm,weather conditions, preservative used, etc.

6. Sap displacement method: Greenround or split bamboos are immersed partly inwater based preservatives. The preservativerises gradually to the top through absorptiondue to replacement of the sap.

7. Hot and cold bath process: Whenpressure facilities are not available, the hotand cold bath or open tank process can beapplied for dry bamboos similarly to that usedfor timber. Absorption of creosote up to 70kg/m3 is reported to have been obtained bythis process. Research studies at the ForestResearch Institute, Dehra Dun indicate thatthe period of heating significantly influencesthe absorption of the preservative. By increas-ing the heating period from 1 hour to 6 hours,the absorption increases’upto 100%.

8. Diffusion process: This process canbe employed using water soluble preserva-tives, either in the form of solution or paste totreat green bamboos.

In this process the toxic chemicals diffusefrom the place of application at high concen-tration to other zone through the watermedium. With enough time the chemical pre-servative spreads to almost the entire volumeof the green material. This diffusion processappears most suitable in the case of bambooswhich are difficult to impregnate under pres-sure in dry conditions. This process requiressimple equipment and are popular in manycountries such as Germany, Canada, U.S.A.,Australia and New Zealand. It appears thatpermeability of bamboo to preservatives issignificantly increased after ponding. Thoughthe service life of the bamboos treated by anyprocess mentioned earlier may not be equalto that obtained by pressure and open tankmethod (where greater degree of quality con-trol is possible), yet the method is cheap,simple and requires simple equipment, appli-cable even in remote areas and further-givesreasonably good protection to the treatedbamboos.

350

9. Pressure processes: Pressure pro-cess is suitable for treating dry bamboos.When the bamboo moisture content isreduced below 20%, satisfactory penetrationand absorption is obtained by this process.The drying of bamboos is generally carriedout in the air under cover. To prevent deteri-oration of bamboos during drying, it is impor-tant to impart prophylactic treatment withsuitable chemicals. For the installation of pres-sure treatment plants, heavy investment isusually required which the average in usercannot afford.

Cracks are usually developed in bamboosif treated under high pressure which reducestheir strength. It has been observed thatspecies having thin walls are susceptible tocracking when treated under low pressures(5-7 kg/cm2). Round specimens of Dendro-calamus strictus treated under high pressureof 14.06 and 28.12 kg/cm2 absorbed 88.12and 107.00 kg/m3 of creosote-fuel oil mix-ture respectively, while half split specimensabsorbed 91.54 and 108.81 kg/m3 of thepreservative.

Traditional Preservation ofBamboo

Insect borers such as powder post beetleare a serious problem. These included Dino-derus minutus Fab., D. ocellaris Steph., andD. brevis Horn., which is popularly known asbamboo “ghoon” in India (Beeson, 1961;Sen Sarma, 1977 and “bubuk bambu” inJava Kalshoven , 195 1).

A non-chemical traditional method ofpreservation is practised quite often in theAsian countries to prevent bamboo againstpowder post beetle. This method is applied bysoaking the cut bamboo culm under thewater. It costs almost nothing and can becarried out by the rural people themselveswithout any special equipment, It is more suit-able for the reasonably cheap and easily avail-able bamboo raw materials (Liese, 1980).

The susceptibility of bamboo to borerattacks depends on the species, its starch con-tent, age of the culm, felling season, and thephysical properties of the bamboo (Plank,

1950). But further studies indicate thatstarch content in bamboo is an importantfactor influencing the susceptibility to borer(Plank, 1950; 1951); the damage caused bythe borer has been found proportional to thestarch content of the bamboo (Purushotham.et al., 1953; Beeson, 1961; Liese, 1980;Tamolang et al., 1980; Sulthoni, 1984).

P l a n k ( 1 9 5 0 ) a n d Beeson (1961)observed that during the soaking period in thewater, the starch contents of the bambootissue is reduced. It is therefore said tobe less attractive thereby improving theresistance level against borers (Liese, 1980;Tamolang et al., 1980). This assumption,however, remains to be proved because notmuch is known about the real effectiveness ofthis traditiona! method of preservation (Liese,1980) .

The rural Javanese have been tradi-tionally practicing this method of bamboopreservation; not only by soaking the half-finished bamboo materials in the water ormuddy water, but also in determining the bestfelling season of the selected bamboo species.They cut the bamboos for their use at acertain season what they call “mangsa tua”,which they believe to be the most appropriatetime, to obtain better quality of bamboos suchas Gigantochloa apus and G. after, used forconstructions. The Javanese have their ownseasonal calendar what they call “prana-tamangsa” (the rule of season). It is actually asolar calendar system, but explicitly ecolog-ically oriented to be in harmony with thesequence of their agricultural activities. Dur-ing the year there are two main seasons (dryand rainy), which are further divided into fourdetailed seasons, i.e., “marengan” (pre-dryseason, 88 days before the real dry season),“katiga” (88 days of real dry season), “labuh”(pre-rainy season, 95 days before the realrainy season), and “rendengan” (94 or 95days of real rainy season). Each detailed sea-son is divided into 3 “mangsa”. but withuneven number of days within each“mangsa”. Mangsa I - VI is grouped as“mangsa muda” (young season) and mangsaVII - XII as “mangsa tua” (old season)(Daldjoeni, 1983).

351

Justification of the JavaneseTraditional Method of BambooPreservation

Research has been conducted by the pre-sent author, supported by IDRC on this sub-ject (Sulthoni, 1983b). The main goal of thestudy was to support with scientific reasonsthe rural Javanese tradition in handling bam-boo for longer service life against powder postbeetle Dinoderus sp.

Two specific objectives were formulated,to, quantify scientifically the time of felling“mangsa tua”, and to assess the efficacy ofthe effect of water immersion of bamboo inimproving the resistance performance againstborer.

Four species of bamboo were used:1. Gigantochloa apus. the most favoured forconstruction. 2. G. otter. specificallyfavoured for furniture and musical instru-ments. 3. Dendrocalamus asper, indefinite,but occasionally favoured for poles due to itstallness. 4. Bambusa vulgaris. minor valueand not favoured for constructional purposes.

The first objective of the research was tojustify whether the fluctuation of the naturalrelative population of the borer synchronizedthe best felling season of the “mangsa tua”.The favoured and not favoured bamboospecies were studied by determining thestarch contents of the monthly consecutivefelling of the bamboo samples, and the corre-sponding degree of susceptibility.

The second objective was to determinethe decrease of the starch content of theimmersed bamboo samples in water forvarious immersion periods, and hence toevaluate their corresponding degree of borerattacks. Southwood method (1978) was usedto measure the natural relative population ofthe borer. while Humphrey’s and Kelly’smethod (1961) was used to determine thestarch contents of the bamboo species. Thedegree of susceptibility in the bamboo speciesagainst attacks was assessed using themethod of Beeson (1961) by counting theborer’s hole per sample.

Results Of The Studies

1. Felling season of bamboo: The

relative population level of the borerDinoderus minutus and D. brevis has a ten-dency to decrease in the “mangsa tua”, andthe lowest in “mangsa” XI (April 20 - May11) (Table 1). Mangsa XI is the best seasonthe Javanese use to cut the bamboos for theirown use. In terms of the biological process ofthe bamboo clumps, “mangsa” XI is about theend of the sprouting period of the shoots.Felling the mother bamboo at this time is notdamaging to the shoots.

Mangsa XII is actually the last “mangsa”of the “mangsa tua”, but the rural people con-sidered it too late to cut bamboos. In Table 1 itcan be observed that the population of theborer increases considerably.

It is concluded from the data in Table 1,that the felling period followed by theJavanese rural people can be recommended.

2. Selection of better quality ofbamboo species: It has been mentionedearlier that the rural people in Yogyakarta,Java, prefer Gigantochloa apus and considerBambusa vulgaris as of minor quality. Table 2shows the average highest starch content inB. vulgaris, which fluctuates between 0.48 upto 7.97% within a year. In G. apus and G.atter it fluctuates between 0.24 to 0.71% and0.24 to 0.64% respectively. The degree ofsusceptibility that the four bamboo speciesindicate is proportional to their respectivestarch contents (Table 3). B. uulgaris shows0.12 to 13.87 boring holes per sample. whileG. apus and G. atter show the most resistantwith boring holes of 0 to 0.81 and 0 to 1.25respectively. D. asper has its susceptibilitydegree between B. uulgaris and Giganto-chloa. with its starch contents fluctuatingbetween 0.27 - 2.80% and boring holesbetween 0 and 5.56. It is clearly provedtherefore, that classification followed by therural people is scientifically justified.

3 . Effect of water immersion on splitbamboo: The results of the study are shownin Tables 4. 5, and 6. with different periods ofimmersion of one. two and three months.The data in the three tables are selfexplaining: all treatments are effective inimproving the degree of resistance in thebamboo treated. either in running or stagnantwater or mud. and the periods of immersions.It is concluded that one month immersion isenough. Bamboo species with less than 1%starch content is considered as good quality

352

bamboo useful for construction. due to its high content of starch. D. asper on

4. Service life of water-immersedbamboo: Traditional preservation has indi-cated to improve the resistance performance,but it depends primarily on the bamboospecies. One year of service life of the treatedbamboo species is indicated in Table 7. In B.vulgaris the service life is still poor and this is

the other hand indicates good performance.ofone year service life with only 2.08 holes ofborer attacks. G. apus and G. after show thebest, even on the control specimen. It is againa stronger indication that least starch contentsin the two latter species promotes better qua-*.lity.

Table 1. Fluctuation of the relative population of Dinoderus beetle in the campus area of Gadjah Mada UniversityYogyakarta. Indonesia (113 m above sea level. tempemture range max. 30-30°C, humidity range max.

75-90% at 2.00 p.m.

M o n t h sRelative pobulation ofpower post beetlesrelated to months

a b C

Javanese “mangsa” and daysRelatrve populatron ofpower post beetlerelated to “mangsa”

a b C

June. 1980July. 1980Aug. 1980S e p . , !980Oct . 1980Nov. 1980Dec . 1980Jan . 1981Feb.. 1981Mar. 1981.Apr. 1981May. 1981

591 439461 82490 63293 119413 164610 189230 138105 88155 6250 219

9 3 13010 lb

116 X I I30 117 II19 11112 IV1 1 V

6 V I4 VI10 VIII1 I X1 X0 X I

( M a y 12 - June 21) (41-t 515 380(June 22 - Aug. 1 1 (41) 551 143(Aug 2 - Aug. 24) (23) 416 53( A u g 25 Sept. 19) (24) 223 94( S e p t 18 Oct 12) (25) 220 46(Oct. 13 - Nov 8 ) (27) 625 194( N o v 9 - Dec 2 1 ) (43) 4 % 246(Dec 22 Feb 2 1 (43) 172 128( F e b 3 - Feb 28) (26) 136 6( M a r 1 - M a r 25) (25) 206 198( M a r 26 - A p r 19) (24) 115 126( A p r 20 - M a y 11) (23) 26 39

8 645lb32

91210

T o t a l 3 701 1 653 217 3 701 1 653 217

Table 2. Average starch content (%) of four bamboo species, based on 12 consecutivemonthly fellings.

B. vulgaris D. asper G. apus G. atterFellingmonths b m a b m a b m a b m a

May, 1980 4.39 3.86 4.00 0.72 0.81 1.18 0.46 0.39 0.28 0.63 0.54 0.42June, 1980 2.77 2.83 5.49 0.41 0.78 0.49 0.29 0.31 0.31 0.49 0.43 0.33July, 1980 0.83 3.42 1.63 0.29 0.31 0.60 0.32 0.47 0.37 0.31 0.30 0.29Aug., 1980 1.33 2.87 3.80 0.27 0.27 0.85 0.27 0.32 0.28 0.54 0.44 0.64Sept. 1980 2.61 3.61 4.53 1.40 2.01 2.80 0.27 0.32 0.24 0.33 0.25 0.24Oct.. 1980 3.55 4.21 6.44 0.35 0.50 0.63 0.26 0.27 0.26 0.29 0.29 0.38Nov., 1980 5.22 5.49 7.97 0.29 0.42 0.66 0.25 0.53 0.71 0.28 0.33 0.34Dec.. 1980 2.31 2.56 3.59 0.26 0.51 0.67 0.25 0.32 0.36 0.30 0.32 0.39Jan.. 1 9 8 1 0.48 0.51 0.52 0.34 0.48 0.62 0.25 0.27 0.27 0.31 0.34 0.33Feb.. 1 9 8 1 0.65 1.60 2.39 1.06 1.17 1.48 0.35 0.31 0.27 0.33 0.24 0.35Mar., 1 9 8 1 2.62 3.63 5.62 2.32 2.52 1.42 0.31 0.27 0.26 0.44 0.34 0.31Apr., 1 9 8 1 1.32 1.66 3.00 0.31 0.33 0.32 0.30 0.46 0.49 0.33 0.31 0.54

Notes: b - basal part of culmm - middlea - apicalAll bamboo samples are about two years old

3 5 3

Table 3. Average Dinoderus beetle attacks (in number of holes) of four bamboo species,based on 12 consecutive monthly fellings, corresponding to the related starch contents

shown in Table 2.

Fellingmonths

May. 1980J u n e , 1980July , 1980Aug. , 1980Sept . 1980Oct., 1980Nov., 1980Dec.. 1980Jan., 1981Feb., 1981Mar., 1 981Apr.. 1981

B . vulgaris D. asper G. apus G. at ter

b m a b m a b m a b m a

13.87 10.50 6.50 0.15 1.43 5.56 0 0 0 0.06 0.06 04 . 6 3 5 . 3 2 2.12 0.06 1.06 1.62 0 0 0 0 . 1 8 0 04 . 7 5 4 . 6 8 3.06 0.06 0.18 1.00 0.18 0.18 0 0 0 07 . 3 7 6 . 3 7 3.18 0 0.18 0.06 0 0 0 0 0.12 0.125 . 3 7 2 . 8 7 1.93 4.25 2.43 4.00 0 0 0 0 0 07 . 3 7 7 . 8 1 4.37 3.00 3.62 3.06 0 0 0 0 0.06 08.43 11.06 5.31 0.81 0.75 0.12 0.25 0.62 0.81 0 0 05 . 4 3 6 . 3 7 4.18 1.25 1.43 1.62 0.06 0 0.06 0 . 1 8 0 . 0 6 0.123 . 9 3 0 . 4 4 4.62 2.00 2.62 2.62 0 0 0 0 . 6 2 1 . 2 5 0.813.25’ 1.68 2.00 1.87 2.87 0.87 0 0 0 0 . 4 3 0 . 7 5 1.061.18 2 . 9 3 1.81 5.25 4.43 3.25 0.06 0 0 0 . 2 5 0 . 1 8 00.12 0.37 0.18 0 0 0 0 0 0 0 0 0

Notes: b - basal part cf culmm - middlea - spical

All bamboo samples are about two years old.

Table 4. Starch contents and the corresponding powder post beetle attacks of 4 bamboospecies after 1 month immersion in water.

First felling Second fe l l ing Third fellingBamboo species Immersion

treatment a b a b a b

1. B. vulgaris Cont ro l 4.09 4 5 3.69 3 9 1.96 2 8Running water 3.16 19 3.48 4 1.50 1Stagnant water 3.39 16 3.38 0 0.33 11Mud 3.31 16 3.29 0 1.61 5

2. D. asper- Control 0 .90 6 0.56 12 0.40 1Running water 0.33 0 0.55 0 0.35 0Stagnant water 0.47 0 0.42 0 0.39 0Mud 0.48 0 0.40 0 0.36 0

3. G. apus Cont ro l 0.37 0 0.30 0 0.38 3Running water 0.30 0 0.25 0 0.35 0Stagnant water 0.23 0 0.32 0 0.26 0Mud 0.33 0 0.32 0 0.38 0

4. G. at ter Cont ro l 0.53 2 0.41 4 0.30 1Running water 0.33 0 0.28 0 0.30 0Stagnant water 0.39 0 0.28 0 0.29 0Mud 0.29 0 0.40 0 0.26 0

Notes: a - Starch contents in percentb Powder post bett le attacks in number of holes after 1 year exposed in openAll bamboo samples are about two years old

All bamboo samples are about two years old. (The results presented in Table 4 and 5 are for the sametreatment Eds)

3 5 4

Table 5. Starch contents and the corresponding powder post beetle attacks of 4 bamboospecies after 2 months immersion in water.

First felling Second fe l l ing Third fellingBamboo species Immersion

treatment a b a b a b

1 . B. vulgaris Cont ro l 4.09 45 3.69 39 1.96 28Running water 2.70 0 2.83 1 1.38 2Stagnant water 2.87 1 3.28 8 0.27 2M u d 3.35 2 2.98 1.39 0

2 . D. asper Control 0.90 6 0.56 12 0.40 1Running water 0.32 0 0.40 0 0.31 0

Stagnant water 0.28 0 0.25 0 0.31M u d 0.43 0 0.25 0 0.33 03 . G. apus Cont ro l 0.37 0 0.30 0 0.38 3

Running water 0.28 0 0.23 0 0.27 0Stagnant water 0.26 0 0.32 0 0.21 0Mud 0.35 0 0.24 0 0.28 0

4. G. atter Cont ro l 0.53 2 0.41 4 0.30Running water 0.26 0 0 0Stagnant water 0.30 0 0 0.25 0Mud 0.30 0 0:27 0 0.22 0

Notes: a - Starch contents in percentb - Power post beet le attacks in number of holes after 1 year exposed in openAll bamboo samples are about two years old.

Table 6. Starch contents and the corresponding powder post beetle attacks of 4 bamboospecies after 3 months immersion in water.

First felling Second fe l l ing Third fellingBamboo species Immersion

treatment a b a b a b

1 . B. vulgaris Cont ro l 4.09 45 3.69 39 1.96 28Running water 2.46 1 1.70 0 0.52 1Stagnant water 3.27 0 1.91 1 0.23 13Mud 3.27 0 1.58 0 1.05 0

2 . D. asper Con trot 0.90 6 0.56 12 0.40 1Running water 0.31 0 0.39 0 0.25 0Stagnant water 0.25 0 0.24 1 0.20 0Mud 0.33 0 0.22 0 0.24 0

3 . G. apus Cont ro l 0.37 0 0.30 0 0.38 3Running water 0.29 0 0.22 0 0.24 0Stagnant water 0.26 0 0.24 0 0.25 0Mud 0.27 0 0.17 0 0.25 0

4. G. at ter Cont ro l 0.53 2 0.41 4 0.30 1Running water 0.29 0 0.21 0 0.27 0Stagnant water 0.24 0 0.25 0 0.25 0M u d 0.25 0 0.18 0 0.18 0

Notes: a - Starch contents in percentb - Powder pos t beetle at tacks in number of holes af ter 1 year exposed in openAll bamboo samples are about two years old

355

Table 7. Powder post beetle attacks of stagnant water-immersed bamboo species as Indicator of the first year service life

Powder post beetle attacks on mdividual bamboo species. in number of holesFellingmonths B vulgaris D. asper G apus C atter

May 1980 10 0 49 19 0 7 0 0 0 0 0 0 0 2 0June 1980 5 0 49 0 1 0 12 0 0 0 0 0 0 0 3 0Jufy I980 5 6 35 0 0 0 0 0 3 0 0 0 2 0Aug. 1980 6 0 53 0 0 0 0 0 0 0 0 0 0 0 4 0Sept. 1980 3 0 45 1 2 0 61 1 0 0 0 0 0 0 1 0Oct. 1980 8 0 27 0 4 0 12 0 0 0 0 0 0 0 0 0Nov. 1980 11 0 27 61 1 0 7 1 1 0 2 0 0 0 2 0Dec. 1980 6 0 63 35 1 0 2 0 0 0 0 0 0 0 0 0Jan. 1981 4 0 21 24 3 0 17 0 0 0 0 0 1 0 15 0Feb. 1981 2 0 29 14 3 0 7 4 0 0 0 0 1 0 15 0Mar.. 1981 3 2 38 20 4 2 44 19 0 0 0 0 0 0 3 0Apr. 1981 0 0 17 0 0 0 1 0 0 0 0 0 0 0 0 0

Total 63 6 453 1 8 2 20 2 170 25 1 0 5 0 2 0 37 05.25 37.75 1 66 14.16 008 0.41 0 16 3 08

Average 0.5 15.66 0.16 2.08 0 0 0 0

Notes: % - untreated specimen - untreated spectmen - 1 month immersion in stagnant water 1 month tmmerston in stagnant water

Data m and are recorded after one month off from the water immerston. whtle and after one year off

Conclusion

The Javanese traditional method of bam-boo preservation is justified to some extent.The felling season followed is suitable.Immersion in water improves the quality ofDendrocalamus asper. Chemical treatment isnot economical and beyond the means of theusers.

References

Anon, 1977. Laporan Feasibility Study PolaKonsumsi Kayu dan Peredarannya diPuiau Jawa dan Bali (Region II). FakultasKehutanan, Universitas Gadjah Mada,Yogyakarta, Indonesia.

Anon, 1982. Timber consumption survey diPulau Jawa. Fakultas Kehutanan, Uni-versitas Gadjah Mada, Yogyakart,Indonesia, 54 p.

Beeson, C.F.C., 1961. The Ecology andControl of the Forest Insects of India andNeighbouring Countries. Government ofIndia, First Reprint, 767 p.

Daldjoeni, N., 1983. Pokok-pokok klimato-logi. Penerbit Alumni. Bandung, Indo-nesia, 176 p.

Haryono Danusastro, et al., 1979. LaporanSuvey Pekarangan. Fakultas Pertanian,Universitas Gadjah Mada, Yogyakarta,Indonesia.

Haryono Danusastro et al., 1980. Ibid.Haryono Danusastro et al., 198 1. Ibid.Heyne, K., 1950. De nuttige planten van

Indonesia. N.V. van Hoeve. Bandung,Indonesia, 1450 p.

Hildebrand, F.H., 1954. Catatan tentangbambu di Jawa. Laporan Balai Penyelidi-kan Kehutanan no. 6 6 . Bogor,Indonesia.

Humphreys, F.R. and J. Kelly, 1961. Amethod for the determination of starch inwood. Anal. Chim. Acta, 24: 66-70.

Hunt, M. and G.A. Garratt, 1967. WoodPreservation. McGraw Hill Book Co.New York, USA, 433 p.

Kalshoven, L.G.E., 1951. De plagen van decultuurgewassen In Indonesia. Dee1 II.N.V. U i t g e v e r i j W. v a n Hoeve.s’Granhage, Bandung, Indonesia. 1065P-

Liese, W., 1980. Preservation of bamboos. InBamboo Research in Asia. Proc. Work-shop Singapore, May 28-30, 1980.

Plank, H.K., 1950. Studies of factors influ-encing attack and control of the bamboopowder post beetle. Fed. Exp. Sta.Mayaguez. Puerto Rico. Bull. no. 48: 39P-

Plank, H.K., 1951. Starch and other car-bohydrates in relation to powder postbeetle infestation in freshly harvested

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b a m b o o . Journ. Econ. Entom. 44(l):73-75.

Purushotham, A., S.K. Sudan and VidyaSagar, 1953. Preservative treatment ofgreen bamboos under low pneumaticpressures. The Indian For. 79(12): 652-672.

Sen Sarma,P.K. 1977. Insect pests and theircontrol in rural housing. Indian Jour.Entom. 39(3): 284-288.

Southwood, T.R.E., 1978. Ecologicalmethods. With particular reference to thestudy of insect populations. ELBS andChapman & Hall, 524 p.

Tamolang et al., 1980. Properties and utiliza-tion of Philippine Erect Bamboos. InBamboo Research in Asia. Proc. Work-shop. Singapore, May 28-30, 1980.

Tewari, M.C. and Bidhi Singh, 1979. Bam-boos, ‘their utilization and protectionagainst biodeterioration. Jour. TimberDev., Assoc. India XXV (4) October.

Varmah, J.C. and M.M. Pant, 1981. Produc-tion and utilization of bamboos. In Bam-boo production and utilization. Proc.

Cong. Group 5. 3A, XVII IUFRO Con-gress. Kyoto, September 6-17, 1981.

Widjaya, E.A., 1980. Country Reports, Indo-nesia. In Bamboo Research in Asia. Proc.Workshop. Singapore, May 28-30,1980.

Sulthoni, Achmad, 1981. Preliminary studyon traditional bamboo preservation inYogyakarta, Indonesia. Paper, XVIIIUFRO Congress. Kyoto, Sept. 6-17,1981.

Sulthoni, Achmad, 1983a. Latar belakangilmiah usaha masyarakat pedesaanmencegah serangan kumbang bubukpada bambu. Kongres Entomologi II.Jakarta, Januari 24-26, 1983.

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Socio-Economics

358

Role of Bamboos in Rural Development andSocio-economics: A Case Study in Thailand

Songkram Thammincha

Department of Forest Management, Faculty of Forestry, KasetsartUniversity, Bangkok 10903, Thailand

Abstract

Bamboo plays an important role in ruraideoelopment of Thailand. Bamboo shootsprovide the rural people with an income inrainy season during which no products areobtained from the major agricultural crops.Bamboo culms are commonly used as con-struction material of the households in ruralarea whereas bamboo handicrafts provide animportant additional incTTome. The wide usesof bamboos give more employment opportu-nit ies and better income distr ibution. Mil l ionsof bamboo culms and thousands of tons ofbamboo shoots are haruested annually. Theoutputs of bamboo uti l ization from dif ferentstudy s ites are presented and the problems ofbamboo resource are discussed.

Introduction

Bamboo is the most universally usefulplant known to man. For over half the humanrace, life would be completely different with-out it. Ubiquitous, it provides food, rawmaterial, shelter, even medicine for thegreater part of the world’s population (Austinet al. 1983). Bamboos are abundant in Thai-land due to its tropical climate. However, thetaxonomic studies of bamboo species in Thai-land is still in its infancy. 12 genera and 41species have been described (Smitinand andRamyarangsi, 1980). Although bamboo haslong been recognized as a multipurposespecies, very useful in rural areas, it is har-vested without any concern for conservationmeasures and research has been virtuallyignored. In the recently formulated SixthNational Economic and Social DevelopmentPlan beginning 198’7, bamboo has beenselected as one of the species to be developed.

This means that the government will have adefinite policy on bamboo resources. Bam-boo will play a more significant role in ruraldevelopment, bamboo cultivation will bepromoted and more effective uses of bamboowill in turn be expected.

Uses and Applications

The uses of bamboo both in Thailand andelsewhere are so broad and the variety ofapplications so numerous, only the moreimportant commercial and common types arecovered in this discussion. Fig. 1 shows thelocation of the places referred to in the text.

Fig. l Location of the study sites.

3 5 9

Bamboo pulp: Bamboo is an excellentresource for pulp and paper making, used inIndia, Japan and other Asian countries for along time. Because of its tong fiber, mixing itwith other pulp is not necessary and can beused as the sole raw material for makingpaper. The Kanchanaburi Paper Mill, pro-ducing paper from bamboo, was establishedin 1936 by the Ministry of Industry, and it wasa successful operation. But the paper mill hadnever been a real money earner. The red tapehad plagued the operation and, as a result,the mill was closed in September 1984.Although the only mill producing paper frombamboo is no longer under operation, the useof bamboo for this purpose is still going onunder the experiment by Phoenix Pulp andPaper Co. Ltd. in Northeast Thailand. Thereis a potential that bamboo may serve as animportant raw material for pulp and papermaking at this mill.

Bamboo plywood: Because of its colourand its shiny surface, bamboo has been usedas a decorative material for centuries. Morerecently bamboo has been made into anattractive plywood for buildings. There aretwo manufacturers of bamboo plywood inThailand, one in Kanchanaburi and the otherin Lampoon (near Chiangmai). Since theproduction requires quite a lot of rawmaterials, there are thousands of peopleengaged in various activities, such as factoryworkers, bamboo cutters, villagers whoweave the bamboo mats. The thickness ofbamboo plywood ranges from 1 mm to 10mm, the size being 120 x 240 cm. The pro-duction capacity is about 20,000 boards permonth in each factory.

Food: Bamboo shoots are widely used asfood in Thailand. The most popular species isDendrocalamus asper, cultivated commer-cially in. Prachinburi where 37,975 tons ofbamboo shoots were harvested last year. Theother varieties are harvested from naturalforests throughout the country. Althoughthere is no actual figure of bamboo shootsharvested from natural forests, it can be esti-mated that some hundred thousands tons ofbamboo shoots are harvested annually. Bam-boo shoots are preserved in three differentways: dried, steamed, and soured bambooshoots. The export value of bamboo shoots,mainly in cans, was 80 million Baht in 1984(US$l = Baht 26.90).

Construction material: In areas whereit grows naturally, bamboo is a traditionalbuilding material. Houses can be made exclu-sively from bamboo. Larger culms are usedfor the piles, stilts and the major framework.Smaller sized pieces are used for floors, win-dows and door frames. The bamboo can besplit into slats for weaving into mat walls.When the culms are split in half and the nodesremoved, they can be used interlockingly toform waterproof roofs. The same ingeniousapplication of bamboo is also carried throughfor furniture, fences, cages, mats, farm imple-ments, ladders, and blinds. Pipes for irrigationand guttering can also be fabricated when thenodes are removed. Bamboo scaffolding iscommonly used in building construction sincebamboo is extremely resilient and longlasting.Many construction workers also believe thatbamboo is safer than rigid tubing. One seldomhears of bamboo scaffolding collapsing evenwhen it is used in multi-storey construction.

A great variety of bamboo handicrafts aremade in the rural area throughout thecountry. They provide the rural people withan additional source of income, Apart fromdomestic consumption, the 1984 export valueof bamboo handicrafts was 70 million Baht.Bamboo handicrafts are also regarded as anold Thai tradition.

Role of Bamboo in RuralDevelopment

Most of the rural people in Thailand are inthe agricultural sector, with major crops beingrice, corn and cassava. They plant bam-boo as a living fence from which bambooshoot will be used for food and bamboo culmfor building material and handicrafts. Thesepeople have no income from their agriculturalcrops during rainy season but they will havebamboo for compensation. The surplus ofbamboo shoots can be sold in the local marketor preserved by steaming or pickling for futureconsumption. Bamboo culms can be cut andmade into a variety of bamboowares for usein the household as well as for additional in-come when sold.

For those living close to the forest,bamboo always shares a major part of theirhouses. It is typical that people in remote rural

360

areas are poor. Their earnings from agriculturalcrops are not sufficient to cover their yearlyexpenditure, many of them being heavily indebt. Fortunately, bamboo can relieve suchproblems. These people will gather bambooshoots from the forest and sell them to thetrader for further processing, The roadsideprice of fresh bamboo ranges from 1 to 5 Bahtper kilogram depending on the time of theyear.’ One can gather as much as 100 kilo-grams of bamboo shoots in a day. With a six-month season one can earn quite a lot ofmoney. With such opportunity for earning thepoor people in the rural areas will be better offand, as a result, the rural areas are developedboth directly and indirectly.

A variety of bamboo handicrafts can befound throughout the country. They repre-sent a unique local tradition which differsfrom place to place. The rural people in eas-tern Thailand have the reputation of makingvery fine bamboo handicrafts while the heavy-duty ones are made in the western region.Many people both Thais and foreigners areastounded to see the very tiny baskets, 1 cmin diameter. In Srisaket and Chiang Maitourists enjoy their shopping for a great varietyof bamboo souvenirs. Bamboo is the mostversatile raw material for home industry in therural area. Bamboo has managed to establishs u c h preeminance because bamboocraftmanship is comparatively simple. While acertain level of competence is necessary, oneneed not possess a high degree of skill tofashion bamboo into an object that will standup for practical use. In fact, there have alwaysbeen a good many people making baskets fortheir own use. Nowadays, specialist craftsmenare outnumbered by farmers for whom work-ing bamboo is secondary trade. Even schoolchildren can make simple bambooware forcommercial purpose.

Housing in the rural area needs quite agreat quantity of bamboo as constructionmaterial, especially for a new settlement inthe remote area, using bamboo as a substituteto timber and other material which are scarceand costly. The versatility of barnboo as con-struction material mentioned in the previoussection indicates the great potential role ofbamboo in rural community development.

361

Socio-Economics of BambooProduction

National bamboo culm production:The quantities of bamboo culms harvestedfrom natural forest and their values from theyears 1981 to 1984 are presented in Table 1.The average annual production is 52 millionculms are worth 270 million Baht. Thefigures represent only the output recorded bythe Royal Forest Department when bambooculms are transported through the checkpoints. In fact, a great number of bambooculms are cut and used in the rural area andare not included in those recorded by theRoyal Forest Department. Consequently, theactual figures of culm production may be fiveto six times greater than those presented inTable 1. The greater part of the culm produc-tion is that of Thyrsostachys siamensis and T.oliveri, the rest being Bambusa arundinacea,B. blumeana, B. nana, B. tulda,Dendrocalamus strictus, D. hamiltonii, D.membranaceus, Cephalostachyum per-graile, C. virgatum, and some other minorspecies. There is no record of the quan- tity of bamboo shoots harvested in the wholecountry. The figure one may get is onlythe estimate. However, the only records ofbamboo shoot production are obtained frombamboo farms and bamboo shoot proceasingfactories. It must be kept in mind that suchrecords represent only a small part of the totalproduction.

Table 1. Outputs and value of bamboosharvested from natural forest in Thailand.

Year outputculms

1981 63 187 919

1982 52 981 878

1983 45 022 244

1984 48 933 933

‘U.S. $1 = Baht 26.90

ValueBaht’

259 272 947

344 924 205

232 827 187

247 583 463

Source: The Royal Forest Department 1981,1982. 1983.1984 Annual Reports.

Bamboo in the north: From touristsouvenir to bamboo plywood industry:Thailand’s major forest resources are found inthe north. This means that the region is veryrich in bamboo resource as well. Apart fromthe uses of bamboo in the households that

represent an old culture of this region, bam-boo is used to make a variety of products forcommercial purposes ranging from tiny itemsto plywood. There are at least 23 manufac-turers of a variety of bamboo products inChiangmai and i ts neighbouring town,Lampoon (Table 2). The production capacitycan indicate that these manufacturers need agreat quantity of bamboo raw material. Bam-boo-based industry differs from other indus-tries in a way that more rural people participatein the production process. The bamboo ply-wood factory in Lampoon is a good example.

The factory produces the standard-sizedbamboo plywood, 1.20 x 2.40 m, with dif-ferent thickness: 1, 2.5,4,6, and 10 mm. Theproduction capacity is 20,000 pieces permonth under 60 percent of full capacity.Bamboo plywood is composed of layers ofbamboo mats glued and pressed together,O n l y Dendrocalamus strictus a n d Cepha-lostachyum virgatum are used. The factoryprovides the members of village farm co-operatives with bamboo raw material. Thevillagers will split the bamboo into thin strips,weave them into 1.30 x 2.55 m mats beforesending them to the factory. The net income ofthe villagers ranges from 35 to 45 Baht perperson per day.

There are about 1,000 families of the ruralcommunity who are involved in the produc-tion of bamboo piywood. There is a labourshortage in the industry during the rainy sea-son when the members spend most of the timeon the paddy fields and other farm lands.

Nearly half of the labour force for bamboo matmaking is shifted to for cultivation activities.The situation is worse during harvesting periodwhen people earn more money and want torelax from hard work. However, the problemis not as serious as it should be since thefactory and the mat makers are dependent oneach other. The factory cannot operate with-out the mats from the rural community, with-out the factory the members of the coopera-tives will have no additional income in orderto improve their living condition. Therefore,both sides have to adjust their view to achievea good cooperation. They are symbiotic.

Tiny bamboo baskets and sweetbamboo shoots in the northeast: Therural people in Srisaket Province have thereputation of making very fine bamboobaskets. Apart from those larger-sized itemsused in the households, the very tiny baskets,as small as 1 cm in diameter, are made fromvery fine bamboo slats. These slats are asfine as a thread, therefore skill and patienceare required when these slats are woven. Thetechnique has been passed on from genera-tion to generation and it symbolizes the oldtradition of the province. The miniature bam-boo baskets are made for, commercial pur-poses as tourist souvenirs, decorative pins inparticular.

There are four villages where such bamboobasket making is concentrated. The results ofthe survey in July 1984 reveal that 53.50percent of the households in four villages, or313 out of 585 households, engage in this

Table 2. Bamboo products in Chiangmai and Lampoon Provinces.

Type of products Number ofproducers

Production capacityunits/month

1. Bamboo plywood

2. Trays

3. Handicrafts

4. Souvenirs

5. Jugs

6. Handicrafts for lacquerware making

7. Lanterns

8. Sticks

9. Toothpicks

20 000(1.20 X 2.40 m)

1 5 0 0 04 3 0 03 8 0 03 4502 0 0 01000

7 0 0 0 kg.

1 000 packs

362

activity. There is one village in which everyhousehold makes the bamboo baskets forcommercial purposes. The income from theproducts for each household ranges from3,600 to 6,000 Baht per year. This additionalincome is very important to the rural people,most of whom earn rather little from theirmain livelihood. There are 24 villages inLoei Province where the people plant the so-called “sweat bamboo”. It is called sweetbamboo because the taste of its shoots is not.bitter. The species are Bambusa burmanicaand Dendrocalamus whose species is notknown to the author. There are 585 farmerswho plant these two species on their landlot.The size of the bamboo farm ranges from 0.5to 10 hectares. However, nearly every house-hold plant sweet bamboo on their homegarden, three to five clumps being the mostcommon.

When planted on the farm land, sweetbamboo can produce 1,600 to 2,400 kilo-grams of shoots per hectare. Each clump in thehome garden can produce shoots weighingup to 100-150 kg. The local market priceof sweet bamboo shoots is 10 to 15 Baht/kg.This can demonstrate that even the ruralpeople who plant sweet bamboo on theirhome garden or as a living fence can earn asignificant additional income. In thenortheastern part of Thailand many peoplestill believe that planting bamboo willbring them death. In the ancient times,bamboo poles were used for carryingcoffin. These people would not plant anybamboo since they believe that they woulddie when the bamboo they planted are bigenough to use as carrying poles. This mightbe one of the reasons why there is very littlebamboo resource in the northeast comparedwith the other regions. This belief is graduallyfading out and the people are beginningto plant more bamboos on their land. Theyhave realized how important bamboo can bein their rural development.

Bamboo products: The lifeblood ofthe rural people in Prachinburi: Bamboois commercially most important in Prachin-buri, with many concentrated bamboo farmsthat support a variety of home industries. Thediscussion will cover only the utilization ofbamboo for commercial purposes. The ruralpeople in Prachinburi usually spend their freetime making items from bamboo. Broommaking is popular among the young and

old people who do not engage in farmwork. The broom handle is, of course,bamboo. A skilled person can make as manyas 50 to 60 brooms in a day, the profit being1000 to 1500 Raht per month per person.Since the brooms are used in every house inThailand there will be a good potential forbroom market.

Cephalostachyum pergracile is a typicalbamboo for use in hat weaving in one district.The bamboo culm will be split into very thinstrips. The strips are woven into bands of 2 cmwidth, before being sewed into a hat. Threehats can be made from one bamboo inter-node. The villagerscan make 60 m of bambooband in a day from which they can earn about10 Baht per day. Although it is a rather smallearning, the rural people can enjoy their addi-tional income.

Bambusa blumeana is used for basketmaking and mat weaving. This bamboospecies is usually planted as a living fencefrom which the culm, 8 to 10 m long, areobtained and are worth 10 to 12 Baht whensold. The net profit the villagers will get fromthe baskets and the mats they make is about15 to 20 Baht per day.

Bamboo furnitures in Prachinburi aremade from Bambusa nana and Thyrsostachyssiamensis. The survey for furniture makingwas made in one village of Prachantakam.There are 213 households in the village, 40 ofwhich are involved in bamboo furnituremaking. The yearly income for each house-hold is about 16,000 Baht. The productionrequires 90,000 culms of Bambusa nananearly all of which are brought from Ubon-ratchatani and Yasothorn Provinces, 400 to500 km to the northeast. Faced with theproblem of raw material, there is a potentialthat more Bambusa nana will be planted inPrachinburi in order to avoid material shortageand long distance transport of bamboo culms.

Dendrocalamus asper was brought fromChina and introduced to the farmers inPrachinburi Province about 80 years ago.This province has since become the most wellknown centre for bamboo farms. The informa-tion about bamboo farms in Prachinburi is pre-sented in Table 3. The f.o.b. price of the freshbamboo shoots ranges from 2 to 8 Baht perkilogram depending on the time of the year.Nearly all of the bamboo shoots harvested from

3 6 3

Table 3. Shout production from Dendrocalamus asper plantations in Prachinburi Provincein 1984.

District

Muang

Prachantakam

Kabinburi

NadeeSrakaew

Srimahapote

Aranyapratet

Kokpeep

Total

Plantingareaha

2 368

480

458

409

56

46

8

4 465

Productiveareaha

2 0 %

256

320

32

24

8

3 5 3 6

output Total Numbertons/ output o f

ha tons factories

11.250 23 580 17

10.625 4 2 5 0 2

9.375 2 4 0 0 210.625 3400 1

9.375 3 750 -

10.000 320 -

8.750 210 -

8.125 65 -

- 37 975 22

the farm are sold to canning factories.Steamed bamboo shoots in cans serve bothdomestic and foreign markets. The number ofcanning factories can very well guarantee thefuture of bamboo farms.

The art of bamboo handicrafts inCholburi Province: A very fine bamboohandicraft can be found in PanatnikomDistrict of Cholburi Province. Cephalosta-chyum pergracile is widely used not only forhandicraft but also for other purposes. Themarket price of one internode about 1 m long,is 5 Baht. There are four bamboo culmdealers in Panatnikom who sell about 12,000internodes per month. The nodes can beused as fuel which is also sold at 10 Bahtper sack or 0.5 Baht per kilogram. Tenbaskets. 12 inches in diameter, can be madefrom the strips of three internodes. The vil-lagers receive 17 Baht for one basket. It is verypromising work for the rural people who invest15 Baht for three bamboo internodes to get170 Baht for ten baskets made. However, itmust be kept in mind that this does not happenevery day since people cannot devote much oftheir time for such work.

A special survey was made at the Handi-craft Cooperatives of one village in Panatni-kOm. The cooperatives were founded in 1976in order to organize the activities of themembers for better quality of products. bettermarketing, and more benefits. Before thecooperatives were founded, the income frombamboo handicrafts was 400 to 600 Baht per

household per month. Such income wasraised to 900-1,200 Baht per month duringthe first six years of the cooperatives. Theincome has been 1,300 to 1,600 Baht permonth since 1982, higher income beingexpected during the years to come.

Kanchanaburi: The centre of bambooutilization: The most concentrated area ofbamboo growth in Thailand is in Kanchana-buri area, 130 km west of Bangkok. Log-ically, Kanchanaburi is the centre of bam-boo utilization in Thailand. It is worth men-tioning that Kanchanaburi is the only pro-vince in Thailand where 12 species ofbamboo are legitimately controlled species.These species are Thyrsostachys siamensis,T. oliveri, A r u n d i n a r i a pusila, A . ciliata,Bambusa arundinacea, B. blumeana, Cepha-lostachyum pergracile, GigantochIoa alboci-liata, Melocalamus compactiflorus, Melo-canna humilis, Schizostachyum aciculare andTeinostachyum griffithii.

21.95 million culms were harvested fromnatural forest in 1982, 22.45 million culmsin 1983 and 14.96 million culms in 1984.These bamboos were used in different kindsof industries both in Kanchanaburi and neigh-bouring provinces.

A special survey was made for theamount of bamboo shoots harvested from theforest. It is impossible to ger the real figure.but the data from some specific studysites will reveal the concentration of bambooshoot utilization. The data was gathered from

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Table 4. Production of sour sliced bamboo shoots in Thongpapoom,Kanchanaburi Province.

ProducerN o .

Number ofwork ing days N u m b e r

WorkersMonth ly wageBaht/person

Produc t ionkg

1 120. 25 800 294 700

2 120 15 1 100 195 000

3 120 4 900 62 500

4 90 5 1 200 125 000

5 60 5 1000 45 000

6 60 8 800 36 000

Total - 62 - 758 200

those who make sour sliced bamboo shoot inThongpapoom, the district next to theBurmese border. The information about soursliced bamboo shoot making is presented inTable 4. These producers employ only 62workers, whose working period ranges from60 to 120 days in a year. Occasionally.other people are also involved. They are thebamboo shoot cutters who sell bambooshoots on roadside for 2 Baht per kilogramon average; the shoots are those of Bambusaarundinacea, Dendrocalamus brandisi and D.strictus. The quantity of sour sliced bambooshoots made in this district can demonstratehow the’ income is distributed to the ruralpeople. There is one bamboo canning factoryin the city of Kanchanaburi that producessteamed bamboo shoots for export to Japan.The production capacity is about 350-400tons per year. Thyrsostachys siamensis andT. oliveri are the only species to be used.Kanchanaburi is and will continue to be thecentre of bamboo utilization in Thailand. Thismeans that the rural people in this region canstill enjoy using this precious gift of nature.

Conclusion

The uses of bamboo have long beenvery well known to man. Since bamboo isubiquitous, people always harvest bamboowithout any conservation measures. Thenatural bamboo resource will diminish inrelation to the depletion of forest area. The

scarcity of bamboo resource in the future willforce people to plant more bamboos for use intheir households and sell the surplus, if any,for additional income.

References

Austin, R., Levy, D. and Ueda, L. 1983.Bamboo. John Weatherhilt, Inc. NewYork and Tokyo.

Royal Forest Department. 1981. AnnualR e p o r t . R o y a l F o r e s t DepartmtntMinistry of Agriculture and Cooperatives.Bangkok (in Thai).

Royal Forest Department. 1982. AnnualReport. Royal Forest Department,Ministry of Agriculture and Cooperatives,Bangkok (in Thai).

Royal Forest Department. 1983. AnnualReport. Royal Forest Department,Ministry of Agriculture and Cooperatives,Bangkok. (in Thai).

Royal Forest Department. 1984. AnnualReport. Royal Forest Department.Ministry of Agriculture and Cooperatives,Bangkok (in Thai).

Smitinand, T. and Ramyarangsi, S. 1980.Country reports: Thailand. 85-90. In:Proceedings of the Workshop onBamboo Research in Asia held in Singa-pore, 28-30 May 1980. Eds. L. G.

L e s s a r d a n d A . C h o u i n a r d . I D R C ,Ottawa, Canada.

365

Genetic Diversity and Socio-EconomicImportance of Bamboos in India

T. A. Thomas, R. K. Arora and Ranbir Singh

National Bureau of Plant Genetic ResourcesCT0 Complex, Pusa, New Delhi-120012. India.

Abstract

India has the richest diversity of bamboosand the total annual production is one of thehighest in the world. Distribution of bamboosin the country, socio-economic role of bam-boos, conservation of gene pool and plant

imprvoement are discussed.

Introduction

The bamboo is an important economicplant intimately associated with mankind sinceancient times. It is a natural gift to the peoplein areas where it is abundant. It providesthe basic necessities of life i.e. food, shelterand clothing. Besides these, it also pro-vides raw material for cottage and paperindustry. Thus it provides livelihood formillions of people. It is no more a poor man’stimber as it serves both the poor and the richwith its numerous useful products. It is arenewable source of energy in the form of fuelfor the rural population.

Bamboo is a fast growing grass withwoody habit. It is widely distributed al1 overthe world. Sharma (1980) has reported about75 genera and 1250 species distributed in dif-ferent parts of the world, mostly confined toSouth-east Asia. India has a rich diversity ofbamboo genetic resources. Bahadur & Jain(1983) reported 113 species of bamboobelonging to 22 genera whereas Sharma(1980) reported nearly 136 species of bam-boos occuring in India. The notable amongthese are Bambusa arundinacea and Dendro-calamus strictus. Although bamboo occurs intropical, subtropical and temperate zones, itprefers humid and warm climate for bestgrowth.

India has perhaps the world’s richestresources of bamboos, with almost 50% of thespecies present in north-eastern region. Bam-boos occupy about 9.57 million hectares offorest area, which constitute about 12.8%of total land area under forests (Vermah andBahadur, 1980). The estimated annual pro-duction of dried bamboos is 3.23 milliontonnes which is about one fifth of total woodproduction of the country (Vermah andBahadur, 1980). It is reported that about 2million tons of bamboo is consumed everyyear by the paper and rayon industries inIndia (Subha Rao. 1966).

Distribution of Bamboos

Out of 22 genera in India, 19 are indige-nous and 3 exotic, introduced for cultivation.The indigenous genera are: Arundinaria,Bambusa, Cephalostachyum, Chimono-bambusa, Dendrocalamus, Dinochloa, Gigan-tochloa, lndocalamus. Melocanna. Neo-huzeoua, Ochlandra. Oxytenanthera ,Phyllostachys, Pseudostachyum, Schizosta-chyum. Semiarundinaria, SinobambusaTeinostachyum, and Thamnocalamus.

Other genera like Guadua, Pseudosasaand Thyrsostachys - are occasionally culti-vated. Vermah and Bahadur (1980) reportedthe bamboo distribution in India as follows: -

In India, as elsewhere, bamboos form richbelts of vegetation in moist deciduous, andsemi-evergreen tropical and subtropicalforests. Very few species occur in theHimalayas of north-western India. The statesparticularly rich in bamboos are ArunachalPradesh, Assam, Manipur, Meghalaya,Mizoram. Nagaland. Sikkim. Tripura and

366

West Bengal. Bamboos are also rich in once in a life cycle. Cultivation of bamboos isAndamans. Baster region of Madhya Pradesh. done by seeds or offsets or by other vegeta-hills of Uttar Pradesh. Bihar. Orissa and tive methods of propagation. Plant heightWestern Ghats. varies from small to very tall. Yield of bamboo

Flowering in bamboos is rare and erratic.In some species it takes place after 3-4 years,in others they flower once in 30 or 40 years,

varies from 2.5 to 4.0 tonnes per hectare,depending upon the intensity of planting,stocking and varieties available. A felling cycleof 3 or 4 years is normally adopted.

Region Number ofGenera

Number ofSpecies

Genus (Species)

1 . North-eastern India

2 . North-western India

3 . Indo-Gangetic Plains

4. Peninsular/South India(Eastern & Western Ghats)

5. Andaman

16 5 8 Arundinaria (9),Bambusa (12).Cephalostachyum (5).Chimonobambusa (6).Dendrocalamus (7).Dinochloa (2).Gigantochloa (2).Melocanna (1).Neohouzeaua (2).Oxytenanthera (2),Phyllostachys (2).Pseudostachyum (1).Semiarundinaria (1).Sinobambusa (I),Teinostachyum (1) ,Thamnocolamus (4).

14 Bambusa (4).Chimonobambusa (2).Dendrocalamus (4),Phyllostachys (2) ,Thamnocalamus (2)

8 Bambusa (4),Cephalostachyum (1).Dendrocalamus (2).Oxytenanthera (1).

8 2 4 Bambusa (3).Cephalostachyum (l),Chimonobambusa (l),Dendrocalamus (1).Indocalamus (3).Ochlandra (9).Oxytenanthera (5).Teinostachyum (1).

6 7 Bambusa (2).Cephalostachyum (I),Dendrocalamus (1).Dinochloa (1).Oxytenanthera (l),Schizostachyum (1).

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Socio-economic Role ofBamboos

Bamboos occupy a very important place inthe economy of the countries in which it iscommonly available and in abundance. Everypart of the bamboo is utilized in one way oranother. It is one of the most useful indigenousnatural resource in India. Out of nearly 10million tonnes of bamboo (annual world pro-duction), about 3.5 million tonnes are pro-duced in China (Sharma. 1980) and 3.23million tonnes in India (Vermah and Bahadur.1980). It provides raw material for cottageindustry and employment for millions. It is esti-mated that harvesting of bamboos in Indiaitself requires about 71.25 million man daysevery year (Vermah and Pant. 1981).

Bamboo has been utilized for paper for along time, but- its utilization for large scalemanufacture of paper is very recent. Nearly80 paper-mills are dependent wholly or partlyon bamboos in India. as they provide long-fibred resource easily available at cheap prices(Sharma. 1980). ‘in Asia, India is the largestconsumer of bamboos for the manufacture ofpaper. Most of the paper mills have beenestablished in the region of large scale bamboogrowing areas. Approximately 2 milliontonnes of bamboo are at present being utilizedfor paper in India. and this leads to a produc-tion of nearly 600.000 tonnes of paper-pulpevery year (Vermah and Bahadur. 1980).There are many advantages of using bamboofor making paper-pulp as compared to otherresources. Bamboo being very fast growing,without bark. long-fibred. cheaply available.supports paper industry with raw material forthe manufacture of newsprint. quality paperand card-board paper.

Commercial exploitation andBamboo improvement

Out of more than 100 species of bamboogrowing in India, only about ten species arecommercial1y exploited. A few other speciesare utilized to a limited extent in cottageindustry. Some of the economic bamboospecies are: Bambusa arundinacea. B. balcoa.B. polymorpha. B. tulda, B. vulgaris, Dendro-calamus brencisii, D. hamiltonii, D. strictus,Ochlandra scriptorea and 0. travancorica

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(Haque 1984). Bamboos are being utilized ina number of ways. The quality of its fastregeneration, strong. straight, smooth, lightand hard wood. easy transportation. splitting.cutting and its glossy surface make it suitablefor making a large number of products for dailyuse. The commonly used articles are mats.basketeries, ropes, beds, brooms, bridges,umbrella handles, pipes, fans, brushes, nails,anchors, fishing rods, furniture poles, agri-cultural implements, ladder and others. Thepresent revenue derived from bamboo is esti-mated at about Rs. 66.77 million per yearwhich can be further increased by encourag-ing bamboo industry (Vermah and Bahadur,1980) .

Inspite of modernisation in industry,demand for bamboos is increasing, There hasbeen constant efforts to increase cultivationarea to meet the demands. Nearly 160,000hectares of new land has been brought underbamboo cultivation in different states of India.Recently bamboos are used as water pipes inBihar state (Vermah and Pant, 1981). Bam-boos are extensively used in building con-struction. Recent research at F.R.I. Dehradunhas successfully used ,it as a reinforcingmaterial, replacing steel in various cementconcrete construction, such as roof shed,beams, electric posts etc.

Use of bamboo shoots as pickles, in chut-neys etc has been increasing. Some specieshave very succulent shoots which are highlynutritious and palatable. These are consumedin a variety of ways. Cultivation of ediblebamboos can increase foreign exchange andtherefore bamboo-shoot farms are important.Leaves of some species form good fodder,especially for elephants. In some species,there is a bitter element - hydrocyanic acidpresent in the leaves, poisonous to‘ theanimals. Bamboo seeds are used as foodgrains at the times of famine.

Living bamboos provide good fencingalong farm houses, gardens and bungalowsserving as ornamentais as well. Some of thedwarf types of bamboos are used as orna-mental plants in trays and pots.

Bamboos are also used in the pharmaceu-tical industry. Extraction of an important drug- Taibashir from the dry-cuims of somespecies of bamboos is well known. The sugarsilica from the cuims is used as a cooling tonicand an aphrodisiac.

Rhizomes of bamboo species are cut intosmall pieces for use as buttons. Bamboos arealso grown for afforestation of denuded landsto check soil erosion. It is a fast growingsource of fuel wood for the rural people.Bamboo charcoal is preferred in gold-smithy.

In India, there is an urgent need to checkdevastation and protect natural vegetation ofbamboos and to increase bamboo cultivationfor meeting the increasing demand. There isa lot of scope in the export of bamboo handi-crafts. Bamboo plantations raised solely forpulp and paper would not be profitable, asthe royalty generally paid by the mills is verylow as compared to the cost of raising theplantation, but bamboo raised for cottageindustry pays good profit as they are sold bythe number of culms. Therefore when thebamboo plantation is raised for pulp andpaper, some of the plants should be ear-marked solely for the cottage industry. Somesubsidy should also be paid to farmers culti-vating bamboo for commercial purposes.According’ to one estimate, bamboo con-sumption in India for;, housing construction isabout 16%, for rural uses about 30% and therest are for paper-pulp and other uses(Sharma, 1980). For increasing bamboo culti-vation, the crop should be included under thesocial-forestry programme.

Since vast genetic diversity of bamboos isavailable in India, there is an urgent need toconserve different species available. ForestResearch Institute, Dehradun (India) hasmaintained the richest collection of bamboogermplasm at present. It has conserved morethan 35 species of bamboos in severalarboreta and are being used for taxonomicstudies, breeding for improved types, timber-engineering, pulp and paper technology, silvi-culture and tissue culture for quick multiplica-tion. Research on physiology of flowering inbamboos is also in progress at various univer-sities in India.

Recently, bamboo has been included asone of the multi-crop programme for study.under “All India Coordinated Research

Project on Under-utilized and Under- .exploited Plants”, scheme approved byIndian Council of Agricultural Research(ICAR) with headquarters at National Bureauof Plant Genetic Resources, New Delhi andresearch centre for bamboos at I.C.A.R.Research Complex for North-Eastern Hills is atBasar in Arundachal Pradesh (India). Activ-ities on survey of bamboo genetic resources innorth-eastern region, and their collectionhave been initiated from 1984-85. Germ-plasm of bamboos will be collected, evaluatedand conserved at the centre.

References

Bahadur K.N. and Jain, S.S. (1983). Rarebamboos of India is’ Published in “AnAssessment of Threatened Plants ofIndia”, edited by S.K. Jain and R.R.Rao; Botanical Survey of-India; Howrah,265-271.

Haque, M.S. (1984). ‘Bamboo - the treegrass. Science Reporters; 2 1: 474-476.

Sharma, Y.M.L. (1980). Bamboos in theAsia-Pacific Region; in “BambooResearch in Asia”, Proceedings of aworkshop held in Singapore, 28-30 May,1980; pp. 99-120; (Ed.) G. Lessard andA. Chouinard, IDRC, Ottawa, Canada.

Subha Rao, T.V. (1966). Bamboo and itsutilization, Indian Forester 92: 186- 190.

Vermah, J.C. and Bahadur K.N. (1980).Country report and status paper on bam-boos in India Forest Records (new series)Botany; 6: l-28.

Vermah, J.C. and Bahadur, K.N. (1980)“Bamboo Research in Asia”. Proceedingsof a workshop held in Singapore, 28-30May, 1980. 19-46; (Ed) G. Lessard andAmy Chouinard. IDRC, Ottawa,Canada.

Vermah, J.C. and Pant, M.M. (1981). Pro-duction and utilization of bamboos.Indian Forester; 107: 465-476.

369

Economics for Bamboo Forestry Research:Some Suggested Approaches

C. W . MacCormac

IDRC, Asian Regional Office, Tanglin P. 0. Box 101, Singapore 9124.

Abstract

Bamboo is a commodity of his toriceconomic value in Asia, Within the context ofa steadily declining total natural forest stock inAsia, bamboo is becoming an increasinglyscarce resource. Public and private initiativesto reverse this trend, should consider bamboocultivation as a viable alternative benejittingpeople both in public (social) and private(market) lands. Bamboo research and subse-quent , development programmes shouldinclude economic analysis as an integral com-ponent for developing appropriate techno-logy and in investing resources for employingthat technology. Specific techniques ofeconomic analysis; i.e. benefit-cost analysis,marginal analysis, budgetting and marketresearch; are suggested vis-a-vis specificbamboo research and developmentobjectives. Foresters are encouraged toinvolve experienced micro-economists intheir research and/or undertake specializedshort-term relevant micro-economics training.

Introduction

From the information provided at the1980 Workshop on ‘Bamboo Research inAsia’ (Lessard and Chouinard, 1980), andin other publications (Austin et al., 1983); it isobvious that in Asia, bamboo is ecologically,socially and commercially an important plant.From, this same literature, plus the results ofrecent research as presented in this workshop;it is equally obvious that there exists a potentialto significantly increase the production of bam-boo .and improve its productivity in presentand alternative uses, In other words, bamboohas ‘value’. It is seen as a relatively scarceresource (due to low productivity of naturalstands) with many uses in manufacturing, as a

370

food and in making paper. Its collectionand/or cultivation, processing and consump-tion involve people from different socio-economic groups in society. With new tech-nology in such areas as - controlledflowering, seed technology, tissue culture,insect control, preservation, etc; it will bepossible to increase extensive and intensiveproduction and improve processing, employ-ing many more physical and humanresources of land, labour and capital.

By definition, economics is a study of theproper method of allocating scarce resourcesamong competing uses (Ferguson, 1972).It attempts to answer the three basic questionsof (Sammedson and Scott, 1968) 1. What toproduce? - what mix of different outputs?2. How to produce? - what techniquesshould be used to produce output? 3. Forwhom to produce. - who should receive theoutput produced? These are relevant ques-tions with respect to scientific research andnational development activities on bamboo toimprove people’s lives.

This paper is a limited attempt to providea rationale for economic analysis of new tech-nology for bamboo production and preserva-tion. The arguments for conducting economicanalysis, and the suggestions for using specifictechniques, draws heavily from the work inFarming Systems Research (FSR) (Banta,1982 Anon, 1984 Anon and Depart-ment of Agriculture Nepal, 1980), and Post-Harverst Research (PH) Austin, 1981;Edwardson and MacCormac, 1984) in Asia,

Bamboo as a Natural ForestResource

Historially, in countries (or regions withina country) with a very low population

density, the forest was considered a“common property natural resource”. Nosingle user had exclusive rights to the forestnor could he prevent others from sharing in itsexploitation. As long as the annual ‘cut’ orharvest from the forest was less than or equalto the annual net natural growth of the ‘stock’of the forest, people’s needs were assured.There was no incentive to control or limitaccess to the forest. This situation no longerexists for Asia today. Since the end of WorldWar ll, rapidly increasing population, withassociated demands for fuel and farm land,and the fact that the developed country wooddemand outpaces supply; has resulted in asignificant decrease in land under forest inAsia. Between 1960-80, one-half of theincrease in food supply in Southeast Asiacame at the cost of extending crop areas inforests’ (Barney, 1980).

The remaining forest areas are generally,in principle, subject to laws regulating theiruse. However, the effectiveness of these lawsare limit&d due to needs of shifting cultivation,the needs for fuel which can be obtained with-out cash by rural (and urban) people, and theability of special interests to disregard the lawswithout penalty. What this means is that tradi-tional ‘natural’ forest stands cannot maintainor increase supplies of wood. While informa-tion on individual species is often difficult toobtain, it is reasonable to assume that theforest stock of bamboo and the total annualnet growth has and will continue to decreasesignificantly under present conditions in Asia.Increasing forest (including bamboo) outputover time by extending the area under cuttingis no longer a long-term option. The rawmaterial for an expanding wood products(including bamboo) demand will be found byintensifying production (Scott, 1982),(perhaps with the exception of Indonesia).

The Potential for EconomicIntensive Bamboo Cultivation

Scott (1982) and Sedjo (1982) discuss thepotential for intensive forest production inAsia. While they focus mainly on monocyclicand polycyclic timber (plantation) systems,several relevant points are made which areimportant regarding the economic feasibilityof bamboo cultivation. Both polycyclic andmonocyclic systems produce significantly

higher mean annual increments (MAI) thannatural forests, The extra costs of physicaland management inputs should be offset fromdirect increased production, and there areother indirect national benefits in increasedemployment for production and wood pro-cessing. Bamboo has a rapid natural earlygrowth which can be increased with applica-tion of fertilizers, Traditional techniques and‘industrial infrastructure’ for processingbamboo exists, therefore expanding produc-tion should be quickly followed by an expand-ing processing sector, provided a marketexists for the extra production.

The shorter the forest species rotationcycle, the less time this ‘capital’ (growingstock) has to be held before disposal. Relatedto this is that the longer the rotation cycle, thelonger input costs are compounded and thelonger future benefits must be discountedback to the present. Bamboo’s very short rota-tional cycle makes it very attractive in terms ofcash flow vis-a-vis other hardwoods and soft-woods. This makes it attractive for those withlittle capital. The comparative net benefit overtime would of course depend on factors suchas the relat ive magnitude of costs andexpected future prices of the species.

Monocyclic plantation systems requirelarge areas and present evidence suggeststhat relative to polycyclic systems; they pre-sent a greater environmental threat due to alack of flora-fauna mix and by sudden exten-sive destabilization of water flows by the dis-turbance of moisture absorbing watersheds.Bamboo seems well suited to poiycyclic har-vesting, can be grown on steep hillsides andalong banks of rivers, its interlocking rootsystem and leaf deposit inhibit soil erosion(Austin, 1983). In Asia, countries have.little high quality arable land left for expand-ing crop area. Efficiency in the use of waterand maintaining soil quality in even marginalagricultural areas, have both direct andindirect benefits to food producers and con-sumers.

Related to some of the above argumentsis the issue (mentioned earlier) of the com-petitiveness of forestry versus agriculture. AsAsian countries move closer to the ‘cleared-forest’ society, the success of forestry willdepend upon its relative (to farming andurbanization) costs and benefits. Bamboo,

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either as a plantation or integrated into afarming system as a crop has potential, formany of the reasons stated earlier. However,it is important to note that in such a situation,the decision to maintain a forest crop (asbamboo) becomes highly decentralized.Region or site specific factors of environment,market demands, relative resource costs andproduct prices, etc will be the key deter-minants. A second characteristic is that thedecisions become more micro-economicrather than socio-political (unless the govern-ment is willing to incur costs in the form ofsubsidies or transfer payments for a perceivedsocial benefit). This means that local com-munities or associations and individual farmhouseholds will also decide if bamboo shouldbe cultivated. This also means bamboo mustbe economic (per unit land area) not justcompared to other tree species but comparedto agricultural crops too. Or at least, it mustcomplement crop production without reduc-ing farm household income. It would appearthat bamboo does have significant potentialfor economic intensive culture. Scientificresearch to produce the necessary technologymust be accompanied by economic analysisto evaluate the ability of that technology toachieve private and social developmentgoals.

Suggested Economic AnalysisApproaches

This section is not a detailed “how to”manual for conducting economic analysis forspecific bamboo forestry problems. Thatwould require a lengthy presentation com-plete with detailed examples and take severaldays to present. Instead, some specificeconomic analysis approaches are listedfollowed by specific bamboo forestry researchand/or development objectives, to which theeconomic approaches could be applied. It isunderstood that bamboo research and/ordevelopment projects can have more thanone objective. How this is handled usuallydepends on the specific situation, Usually,secondary objectives. are expressed as con-straints for selecting techniques to achieve themain objective (Gregersen and Contreras,1979) (i.e. increasing bamboo output forpaper making is the main objective butenvironmental objectives help determine har-

vesting techniques). It is up to researchers tobe aware of the social and private decisionmakers’ objectives and the relative weightingthey give to those objectives, in the designand evaluation of new bamboo productionand processing technology.

Benefit-Cost Analysis

Economic (Social): This form ofeconomic analysis has been widely used inthe natural resources to help assess theeconomic efficiency, from society’s point ofview, of new technology. It attempts to iden-tify and quantify costs and benefits to society(not just individuals) by utilizing resourcesover a specified time period. It is not depen-dent only on known market prices for inputsand outputs but estimates values for suchthings as increased or decreased soil erosion,reduced unemployment, improved foreignexchange earnings, and other public “badsand goods”. In the case of bamboo, this typeof analysis can, for example, be used wherethe objective of research is to - develop andimplement techniques for environmental soiland water conservation, soil improvement,shelterbelts, and increase the area underforest. The costs and benefits of those objec-tives are not only shared or consumed byspecific individuals but by ‘society’ or groupswithin society. This analysis calculates the“net benefit” or “return” to society employingalternative bamboo techniques.

Financial (Private): This form ofanalysis calculates the costs and benefits toidentified individuals and organizations usingmarket prices only. The same methodologyof discounted (over time) cash flow is used asin Economic Benefit-Cost Analysis, howeverthe focus is on calculating the net benefit andreturn to the actual equity capital invested inthe new technology. In the case of bamboo,this type of analysis can, for example, be usedwhere the objective of research is to -maximize economic’output per unit time for avariety of market uses, i.e. paper-making,furniture, food; minimize costs of productionand processing for a given quantity of bam-boo cultivated or processed; and to developeconomical techniques for improved qualityof bamboo and bamboo products.

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In both forms of Benefit-Cost Analysis,there are three main criteria by which a singleor set of techniques can be assessed andcompared. These are: (i) Benefit-Cost ratio:This is simply the total of the present worth ofexpected benefits divided by the total of thepresent worth of expected costs. Onlytechnologies with a ratio of greater than 1 areeconomically efficient in terms of resourceuse. (ii) Net Present Worth (sometimesreferred to as net present value): This is thedifference between the present worth of theexpected benefits less the present worth of theexpected costs. All technologies which resultin a positive net present worth are econom-ically efficient in terms of resource use.(iii) Internal Rate of Return: This is defined asthe average earning power of the value ofresources used from the application of thetechnology. Only technologies that give a rateof return higher than the existing marketinterest rate are resource efficient.

The formal mathematical statements ofthese criteria are given below (Gittinger,1976) :

Benefit-cost ratio =t = l

n

t=l

n Bt - CtNet present worth =

t = l

Internal rate of return is that discount rate isuch that

Bt - C t- 0

t = l

where,Bt = benefits in each year.ct = costs in each year.t = 1, 2 ,........ n.n = number of years.i = interest (discount) rate.

It should be noted that in comparing alter-native (bamboo) technologies if due toresource constraints, only one of the alterna-tives can be employed, a comparison of thenet present worths of the alternatives is theappropriate selection criteria.

The Single VariableInput-Output ProductionRelatioship "

Consider a product Y (bamboo, in kg),whose yield depends only on one input X(fertilizer, in kg) assuming all other inputs areused at a constant level. Where a unit offertilizer is added, total output increases bysome amount. Extra output resulting from 1kg increase in fertilizer is called the marginalproduct of fertilizer (MPx). When multipliedby the price per kilogram of bamboo, weobtain a monetary measure called the mar-ginal value product (MVPx) . The MVP repre-sents the value of extra bamboo resultingfrom the application of an additional kilogramof fertilizer. On the cost side, the addition of akilogram of fertilizer increases costs by a cer-tain amount. This is called the marginal factorcost (MFC). It is equal to the price of the ferti-lizer, since increasing the use of fertilizer byone unit increases cost by an amount equal tothe price of the fertilizer. Hence, using therule stated above, the use of fertilizer shouldbe increased as long as its MVP is greater thanits MFC. To identify the optimum level offertilizer, that is, the level where profits aremaximized, we need to observe how produc-tion responds to fertilizer application. Assumethat the output-input relationships are asshown in columns 1 and 2 in Table 1.

These show that when fertilizer (x) isincreased, bamboo yield (Y) generallyincreases. At Iow fertilizer levels, the increasein yield from each 10 kg of fertilizer used islarge. However, the yield increases from eachunit of input (10 kg fertilizer) become smallerat successively higher levels of the input. Inother words, extra yield (marginal product)tends to decrease at successively higher ferti-lizer levels if all other inputs are held constant.This observation is usually referred to as thelaw of diminishing marginal returns andapplies to all input-output situations. In Table1, percentage of yield increase begins todecrease when more than 30 kg of fertilizer isapplied. This reflects the law of diminishingreturns. Total yield begins to decrease whenmore than 100 kg of fertilizer is applied, butthis decrease in total yield is not a necessarycondition of the law of diminishing returns.

Column 3 of Table 1 shows the marginalproduct as fertilizer is increased in 10 kg units.

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Table 1. Illustration of a simple input-output relationship.

Fertilizer Yield(kg) (kg)

Marginal Value of cos t o fProduct ext ra output ext ra input

(kg) (M)’ !" (M)

0 2000 -

10 2100 10020 2300 20030 2600 30040 2800 20050 2900 10060 2950 .5070 2980 3080 3000 2090 3010 10

100 3010 0110 3000 -1

"! * M is used as monetary unit.

At fertilizer levels above 30 kg, yield increasesbut marginal product decreases. We saydiminishing returns has set in at 30 kg ferti-lizer. Assuming bamboo price is l.l0/kg,column 4 shows the value of extra output, orthe marginal value product (MVP), which isobtained by multiplying MP by the unit priceof bamboo. MVP equals the additional valueof output resulting from each 10-kg increasein fertilizer. Column 5 shows the cost of extrainput or the marginal factor cost (MFC),which equals the increased cost of each addi-tional IO-kg bag of fertilizer. If fertilizer price is4/kg, a l0-kg increase in fertilizer will raisecost by 40. Therefore, marginal factor costequals 40 because we are dealing with l0-kgbags of fertilizer,

Using this information, we can determinethe quantity of fertilizer that will maximizeprofits by following the rule that additionalfertilizer should be applied as long as extrareturn (MVP) is greater than extra cost(MFC). It is sufficient to compare columns 4and 5. We can see it pays to increase fertilizeruse up to 60 kg because value of additionaloutput (MVP) is greater than additional ferti-lizer cost at levels lower than 60 kg.

Does it pay to increase the fertilizer levelup to 70 kg? The larger value of the bambooobtained from using more fertilizer is 33.Additional cost is 40. The farmer would belosing 7. Clearly, this will mean a reduction innet profit. Hence, he should stop at 60 kgwhere profit maximization occurs. To confirm

-110.00220.00330.00220.00110.0055.0033.0022.0011.00

0-11.00

4040404040404040404040

that profit is maximized at 60 kg of fertilizer,compute total profit at each fertilizer level.This is illustrated in Table 2.

Columns 1 and 2 are the same figures asin Table 1. Column 3 is obtained by multiply-ing yield by the bamboo price (l.l0/kg).Column 4 is obtained by multiplying theamount of fertilizer applied by its price per kg(4/kg). Column 5 shows net return, whichequals value of production less total cost.

Note that profit increases as fertilizer isincreased from 0 to 60 kg. Maximum profit isobtained at 60 kg fertilizer. Beyond 60 kg, netreturn decreases. Note also that maximumyield (at 90-100 kg fertilizer) does not meanmaximum profit.

Although this illustration is simple, itprovides a guideline for determiningmaximum profit level of input use. We com-pare the marginal value product with themarginal factor cost. This analysis showsinformation on marginal productivity of aninput can be expressed in monetary termsand compared with the input price. WhenMVPx>Px, less input is being used thanwould maximize profits. When MVPx<Px,too much input x is being used. Because thelaw of diminishing returns generally holds forall input-output relations, the profit maxi-mimizing level of any input will be less thanthe yield maximizing level. Note that yieldwas highest at 90 kg fertilizer but profits werehighest at 60 kg fertilizer.

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Table 2. Illustration of how to compute total profits.

Fertilizer Bamboo Total Value Total Cost Net(kg)

1(kg)2

of productiona of fertilizerb returnsc3 4 5

0

:i3040506 07 08 090

100110

2000 2200 0 22002100 2310 40 22702300 2530 80 24502600 2860 120 27402800 3080 160 29202900 3190 200 29902950 3245 240 30052980 3278 280 29983000 3300 320 29803010 3311 360 29513010 3311 400 29113000 3300 440 2860

aColumn 2 X 1.10. bColumn 1 x 4. cColumn 3 less 4

Budgets

Budgets are one of the simplest yet mostwidely used techniques in economic analyses.Budgets are used: i) to compare economicprofitability of - different technologies; ii) toindicate whether a proposed change (i.e. newtechnology) will be profitable under a givenset of circumstances; and iii) to explore con-ditions under which certain technologiesbecome profitable or unprofitable.

Enterprise budgets, partial budgets, andparametric budgets are the three commontypes.

(i) Enterprise budgets: The process ofproducing a particular commodity is calledenterprise. Small farms in tropical Asiausually are multi-enterprise farms - theyproduce more than one commodity possiblyincluding bamboo. Enterprise budgets enableus to evaluate costs and returns of productionprocesses. Comparing relative profitability ofnew technology with existing technologyhelps to show how the enterprise can be moreprofitable. The new technology may changeexisting technology to show a better way togrow bamboo or to compare possible newcropping patterns including bamboo.

A budget is a formalized way to compareproduction process benefits and costs. Ifbenefits exceed costs, profit was earned. Ifbenefits are fess than costs, a loss wasincurred. The difference between grossreturns and variable costs is called the grossmargin (also referred to as returns above vari-

able costs). Gross margin measures thecontribution of an activity to profitability.Input quantities and values used in produc-tion process (costs) and output quantities andvalues (benefits) are the basic data requiredfor budgets.

(ii) Partial budgets: Partial budgets areused to evaluate the effects of a proposedenterprise change. A partial budget is usefulonly when the change is relatively small. Apartial budget highlights variations in costsand returns caused by proposed changes inthe enterprise. Only items affected by thechange are included in the budget. Levelsand costs of all unchanged inputs are notincluded. When constructing a partial budgetidentify: costs that will increase or decrease,and returns that will increase or decrease.

Table 3 shows a basic partial budget. Theleft side shows negative effects of a proposedchange - added costs and reduced returns ofchanging from an old to a new technology.On the right side are the positive effects -added returns and reduced costs. If positiveeffects exceed negative effects, proposedpractice is more profitable than the existingproduction practice.

(iii) Parametric budgets: For any newtechnology, estimates of inputs and outputsare approximate, and prices are subject tochange. Therefore, it is useful to explore howsensitive benefits are to changes in assumedlevels of inputs, outputs, and prices. We oftenwant to learn what yields and/or prices arenecessary to make a technical change profit-

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Table 3. Partial budget to estimate changein annual net cash income resulting from

some change in resource use.

a. Added cos t s c. Added returns Mb. Reduced re turns d. Reduced costs M-

S u b t o t a l A : M S u b t o t a l B : M

E s t i m a t e d c h a n g e ( B - A ) M

able. Parametric budgets, also called sensi-tivity analyses, answer these questions. Thesimplest situation to consider is the change inprofit if one parameter is varied. Gross marginis then calculated as:

GM = (PXY) - VC

where

GM = total gross marginY = bamboo yield

(the factor to be varied)P = the price of bamboo, andVC = total variable cost.

Gross margin can now be calculated forany yield within the range that yields areexpected to vary. Table 4 presents grossmargin for a range of yields between zero and4,000 kg/ha. The data are also plotted inFigure 1. The figure shows that a yield of lessthan 1,198 kg is a loss for the enterprise. Thisyield is usually called break-even yield, calcu-lated by solving for Y when (PY) - VC = 0.It is where the producer just recovers variablecosts.

Market Research

Market research is an important type ofeconomic research with respect to the devel-opment and recommendation of new techno-logies for growing and/or processingbamboo. For a,government or private institu-tion (or private individual) to invest in newbamboo technology, it is essential to havedata on input markets (resources used inbamboo production or processing) andoutput markets. The main marketing aspectsto be considered in a market study are(Ranaweera, 1984) : (i) input supplies,(ii) expected output increases, (iii) marketpotential (demand), (iv) capacity of the mar-keting system to handle increased output,and (v) anticipated government interven-tions.

Table 4. Effect of changes in yield on grossmargin "! .

Yield (kg/ha) Gross margin (kg/ ha)

0 -12581000 2082000 8423000 18924000 2492

‘ G M = ( Y x 1 . 0 5 ) - 1 2 5 8 .

-2000 10

Yield (kg/ha)

Fig. 1. Effects of changes in yield levels in grossmargin.

Conclusions

This paper has had two objectives. First,define a role for economic analysis as part of atotal research effort to develop new techno-logies for bamboo cultivation and utilization,and second , suggest specific economicanalysis procedures that could be used. Thematerial presented for the second objective isvery superficial, in that the reader is stronglyrecommended to consult the references citedfor developing even a basic understanding ofthe related economic concepts and tech-niques. It is also recommended that agri-cultural or resource economists withexperience in micro-economic analysis beencouraged to undertake this research. Muchof this analysis could be done by foresters if

376

they have received appropriate training (aminimum of 6-8 weeks) from economists.The decisions to include an economist and/ortrain foresters in basic micro-economics forthis research should depend on: (i) how‘basic’ or ‘applied’ the bamboo research is,(ii) the existing availability of interestedand/or experienced economists, and (iii) theresearch and training resources available.

ReferencesAnon, 1980, Workshop on Economics and

Cropping Systems. IRRI and Departmentof Agriculture, Nepal.

Anon, 1980. Profit Zmprouement throughOperations Analysis. Management andProduction Centre, B.C. Research,Vancouver, Canada.

Anon, 1984. Basic Procedures for Agroeco-nomic Research. IRRI, Philippines.

Austin, J.E. 1981. Agro industrial ProjectAnalysis. EDI Series in Economic Devel-opment John Hopkins Press. USA.

Austin, R., Ueda, K. and Levy, D. 1983.Bamboo. Weatherhill Inc., New York.

Banta, R.G. 1982. Asian Cropping SystemsResearch - Procedures for Microeco-nomic Evaluation. IDRC, Ottawa,Canada.

Barney, G .O. 1980. Global 2000: Report toPresident. US Government PrintingOffice. Washington, D.C.

Brown, M.L. 1979. Farm Budgets: FromIncome Analysis to Agricultural ProjectAnalysis. World Bank Staff OccasionalPaper No. 29. World Bank, USA.

Edwardson. W. and MacCormac, C.W.1984. Improving Small Scale Food lndus-tries in Developing Countries. IDRC,Ottawa, Canada.

English, H.E. and Scott, A. 1982. RenewableResources in the Pacific. IDRC, Ottawa,Canada.

Ferguson, C.E. 1972. MicroeconomicTheory. Irwin Series in Economics, NewYork.

G. Henger, P. J. 1982. Economic Analysis ofAgricultural Projects. ED1 Series inEconomic Development. John HopkinsPress, USA.

Gregerson, H.M. and Contreras, A.H. 1979.Economic Analysis of Forestry Projects.FAO Forestry Paper No. 17, Rome.

Hoekstra, D.A. The Use of Economics inDiagnosis and Design of AgroforestrySystems. ICRAF Working Paper No. 29.

Horton, D.E. 1984. Social Scientist in Agricul-ture Research, IDRC, Ottawa, Canada.

Lessard, G.L. and Chouinard, A. 1980. Bam-boo Research in Asia. Proceedings of aWorkshop. IDRC, Ottawa, Canada.

Ramsey, F. and Duerr, W.A. 1975. SocialSciences in Forestry: A Book of Readings.

Ranaweera, N.F.C. 1984. StudyingMarketing Systems. In Basic Proceduresfor Agroeconomic Research. IRRI, Philip-pines.

Sammedson and Scott. 1968. Economics: AnIntroductory Analysis. McGraw-Hill,Toronto, Canada.

Scott, A. 1982. Intensive and Optimal Devel-opment of Forest Lands. In RenewableResources in the Pacific (ed: English, H . E.and Scott, A.). IDRC, Ottawa, Canada.

Sedjo, R.A. 1982. Forest Plantations, Pro-duction and Trade in the Pacific Rim. InRenewable Resources in the Pacific (ed:English, H.E. and Scott, A.). IDRC,Ottawa, Canada.

Reports on Sessions

378

Reports on Technical SessionsTechnical Session.1Chairman: Prof. Mu Zhowg LunRapporteur: Prof. A. N. Rao

In the technical session I on Monday, 7October 1985 six papers were presentdduring the morning and afternoon sessions.

1. In the first paper presented by MrSharma, the general importance of bamboosin the Asia Pacific region was stressed. Thepresent status of bamboo production and usein India, Bangladesh, Thailand, Malaysia,Philippines, Indonesia, Papua New Guinea,Sri Lanka, Burma, Korea, Japan and Chinawas briefly reviewed. The assessment for thetotal bamboo resources is available only forsome of the Asian countries, especially thosewhere bamboo is used as raw material forpaper industries. The importance of a goodassessment for each country was emphasisedespecially where bamboo is an importantcomponent of the cottage and rural indus-tries. Both the research output and theimprovement of cultivation techniques areimportant to increase the bamboo resourcesand altogether about 12 suggestions areoffered. The paper was well received andduring discussion particular points regardinggregarious flowering habit, hormonal andwater relationships, utilisation of abandonedland, suitability of bamboos to be used aswater pipes, salt tolerant varieties and theother related aspects were covered.

Professor Wu Bo presented his paper on‘The present condition of bamboo researchand production in China’ and reviewed thedevelopment of bamboo industry in hiscountry. For most of the audience this was anexcellent introduction to the status of bambooresearch undertaken in China and the highquality bamboo production in enormousquantities.

In the next paper presented by Dr SallehMohd. the bamboo resources in Malaysia wasreviewed with plans and strategies for furtherdevelopment. In view of the other forestresources available in great abundance dueemphasis is not given so far for bamboos. Theannual production of bamboos for the wholecountry is not estimated, though figures forcertain states like Kedah, are available.

Several cottage industries in the country usingbamboo as basic material are adequately sus-tained. Regarding the development strategiesenough technology should develop toimprove the bamboo based, rurally centredsmafl scale industries and the techniques forharnessing and managing the raw materialsshould improve. After presentation there wassome useful discussion on the virtue of selec-tive cutting, usefulness of aerial surveys andproper methods for the administration ofbamboo projects and other related aspects.

Bamboo in Indonesia - a country reportwas the next paper presented by DrHaryanto. The cultivation of bamboo is anancient art in Indonesia and along withbanana as well as coconut (popularly knownas BBC), they provide both food and buildingmaterials for the rural population. The smallholdings around villages Pekarangans aremillions in number covering about 31,700 haas against 50,000 ha of bamboo land as partof the natural forests. Research on cultivationand utilisation is carried out in universities andresearch institutes and further progress isnecessary to meet the demand of the peoplein the 21st century. Many questions wereasked about the selective harvesting, curingand treating of bamboos.

Professor Lantican was the next in pre-senting the paper on ‘Bamboo productionand utilisation research in Philippines’. Bam-boos are extensively used in Philippines in thefishing, banana and furniture industries. Thehandicraft and furniture industry, based onbamboo resources brings considerable foreignexchange. Other uses of bamboo in buildingconstruction, for flooring, pulp and paperindustry were explained. Research needs toimprove the production and utilisation of dif-ferent species were outlined and the researchpriorities were listed. After the paper presen-tation there was some discussion on the rateof bamboo production/given land area andthe dissemination of information on bamboosin the region.

The next paper was the ‘country report -Sri Lanka’ by Dr Vivekanandan. Bamboosare mostly used for rural housing. Of theseven genera and 21 species present in thecountry only Dendrocalamus strictus hasbeen planted on a large scale, The progress of

3 7 9

research work done in the previous year as apart of the IDRC project was outlined whichconcerns about the s tem propagat ionmethods in Bambusa vulgaris. Other condi-tions suitable or large scale propagation wereexplained and discussed. After the presenta-tion there was discussion on the suitablemethod of planting and the effects ofhormone treatment to improve the growth ofthe propagules .

As the last paper of the session I, Dr Boapresented a brief report on ‘Bamboos inBangladesh as the other invited membersfrom Bangladesh could not at tend theseminar. There is a total area of 54,000 ha ofbamboo forest in the country in addition tobamboos grown in and around the villages.Recently an inventory was prepared for thewhole country and the cultivation of bamboois increasing. However, there is very littlespace available for bamboos growing and dueto water logging bamboos die in certain areas.Forest bamboos are thin and mostly used forpaper. Both overcutting and extraction arethe real problems. Many improvements toremedy the situation were suggested.

After the presentation of all the papers therapporteur summarised the main points thatemerged from the presentation of papers andthe discussion followed, which included thefollowing:

1. There should be some standardisationin the recognition of the various species.

2. A good network for the exchange ofinformation on bamboos is urgently required.

3. The cost of production and the relativeeffectiveness of different methods presentlyfollowed should be carefully studied since thebamboo resources are fast disappearing inmany countries.

4. There is an urgent need for extra pro-pagation material in every country to usebamboos as soil binders and to prevent soilerosion.

5. Destruction of bamboos for better landuse is a myth since most of them grow only onmarginal soils.

6. Greater attention should be paid torecognise genetic variability available withinthe species to select better varieties for cultiva-tion. Many of the taxonomic problems needto be solved to eliminate duplication ofspecies and to establish the new ones, if needbe.

At the very end of the session a requestwas made to all the authors to submit theoriginal copies of their papers includinggraphs, figures, diagrams etc. Wherevernecessary each paper will be discussed withthe individual authors to make the necessaryamendments and to establish proper formatfor publication of the proceedings,

Technical Session IIChairman: Prof Geng BojieRapporteur: Prof Y M L Sharma

Six papers were presented during the session.

In the paper presented, Mr Stapleton,(Nepal) spelt out the efforts initiated by himon vegetative propagation techniques in barn-boo (few important species) for evolving anefficient and appropriate technology to suitethe topographic, climatic and biotic factorsprevailing in Nepal. His paper stressedon the efforts to induce quick rooting of bam-boo species to achieve maximum percentageof success in the field.

In an interesting and illustrated paper, MrHansken of Panda Products, USA, detailedthe efforts made to propagate Phyllostachyspubescens, and raise seedlings for supply tothe people. It is a very enterprising ventureaimed at propagating Phyllostachyspubescens, and reminds of some privatefarmers in Tamil Nadu of India raising seed-lings for supply to cultivators for raising bam-boos in the agricultural sector.

Mr Fu Maoyi in his paper highlighted thebenefits of the application of fertilisers to raisethe bamboo crops including the methods ofapplication, dosages and the result of applica-tion of such fertilisers. It has been reportedthat the fertiliser application helps greatly thegrowth of bamboos. In fact the current trendis the use of more and more of fertiliser inforestry crops.

In her well presented paper, Miss ChenFangne highlighted the hybridisation work onbamboos carried out in China. She has alsohighlighted the characters of pollen of bam-boos and other features like the period ofseed ripening, stressing the importance of theviability of pollen as the key factor in the suc-cess of these hybridisation work.

Presenting his paper, Dr Eric Boa detailedthe different pests and diseases of Bamboo inBangladesh. The culm sheath regions were

3 8 0

reported to be the vulnerable places of Details on tissue culture of bamboosinfection. He has also cautioned about thedrawbacks in raising large scale monoculture

created some interest with questions on the

of bamboos.explants used for the experiments and themeristemable tissues.

In his second paper, Dr Eric Boa high-lighted the incidence of bamboo blight diseasein some parts of Bangladesh, especially in thevillage bamboos. He stressed the need for amore intensive study of the subject, and todetermine the predisposing factors. It wasalso suggested by the Rapporteur the possi-bility of growing bamboos in mixtures withtree crops, and the need to prevent thespread of the disease across the borders ofBangladesh.

Technical Session IVChairman: Dr Walter LieseRapporteur: Dr Celso Lantican

Technical Session IIIChairman : Prof Hsiung Wen-yueRapporteur: Dr Salleh Nor

Ten papers were presented in this session.

The paper on Anatomy and Properties ofBamboo was presented by Dr Walter Liese.With the aid of slides, Dr Liese gave a com-prehensive account of the present state ofknowledge about the anatomical, chemical,physical and mechanical properties of bam-boos. For many of the properties, he indicatedthat variations exist along the height andacross the wall of a culm.

Three papers were presented in this session.

According to Dr Anan Anantachote, bam-boo is a very important resource in Thailand,but it is decreasing in quantity; the silvicsunknown. Thus, his study focussed on thebasic flowering characteristics of economicbamboos in Thailand. High variability in seedgermination percentage, the correlationbetween moisture content and presence ofseed borne fungi are important. During dis-cussion, clarifications were sought on actualseed M.C., which is the air dry M.C. and onthe seed borne fungi which has not been usedfor inoculation tests yet. On the question ofphysiological changes before flowering, DrAnan replied that when clumps do notproduce new shoots, it is likely that they willflower the next dry season.

During discussion the following questionswere raised.

1. Is penetration of preservatives possiblethrough the stomata of the center walls?

Preservatives enter by diffusion. Thereare no stomata on the walls.

2. You mentioned that bamboo shrinkseven when it is still green. Can you tell uswhat the fiber saturation point of bamboois?

This is a subject that still needs to beinvestigated.

3. When is a culm mature and why does aculm senesce?

Dr Usui of Japan discussed in detail thestudies on morphology of a number ofJapanese bamboos. Morphological studiesmust be supported by other basic research inanatomy and taxonomy. On a questionwhether branching of bamboo is regulated byarrangement of prophylls in a bud, it was leftunanswered.

Little research has been done on anatom-ical changes as the culm gets older. Thework of Dr Chen at Nanjing has shownthat there is a dramatic and puzzlingincrease in the elements of older culms.We do not know why a culm senescesand why it becomes brittle and loses itsstrength.

In his presentation, Prof Rao, Singapore,focussed on the growth, anatomy, taxonomy,cytology and reproduction of certain bam-boos in Singapore. Following there was asecond presentation on the preliminary workon tissue culture of certain bamboos.

The next paper was by Dr Higuchi onCharacterisation o f Steam-explodedBamboos for Cattle Feed. The paper, pre-sented with slides, described the use of thesteam explosion process to convert bamboochips into a form that can be hydrolysed bycellulose. According to the author, the pro-cess is promising for the production of cattlefeed and obtaining the material for fermenta-tion.

381

Questions were raised during discussion :

In Germany, it has been observed that incattle dungs the parenchyma cells bearingthe warty layer are not digested. What isyour finding on EXB’s?

Ruminants cannot digest the ceils if theyare covered with lignin. EXB’s are devoidof lignin as this is separated in theprocess.

The paper on Anatomy and Properties ofBamboo by Dr Janssen dealt with the struc-ture, properties and advantages of bamboo asthe building material. The information givencentered on mechanical properties that areuseful for designing bamboo structures.

In the next paper, Mr Li showed thatstrong bamboo structures, much bigger in areaand taller than ordinary houses, can be suc-cessfully built as has been done in Switzerland.

The discussion followed the presentation.

How do you put the base of the culm onthe ground?

It is erected on a concrete foundationwith a steel plate bolted.

What material was used to tie the culmstogether for the columns of the building?

Bamboo skin strips and steel strips.

I am of the opinion that construction withbamboos require a lot of skill, which isabsent in Malaysia. Are there any schoolsor courses dealing with construction ofbamboo structures in China?

Yes, some schools have. (Note: Someparticipants offered the information thatsome publications dealing with the sub-ject are available).

Did you have to secure permits andinsurance for the bamboo building youput up in Switzerland?

These were arranged by the Swissgovernment.

Mr Achmad Sulthoni presented the paperon Traditional Preservation of Bamboo inJava. The results of a study involving the useof certain traditional methods of improvingthe service life of bamboo were outlined. Itwas concluded that the existing practicesregarding the time of cutting and waterimmersion has scientific basis and therefore

the methods outlined are recommended.

The following questions were raised.

Did you try to relate the biological lifecycle of beetles with the occurrence ofbeetle attack?

382

I studied the beetles involved but was notable to correlate the life cycle changesand the occurrence of the attacks.

The loss of starch in culms soaked inwater is it caused by bacteria1 actionrather than by leaching?

I believe it is due to bacteria becausestarch is not soluble in water.

Mr J N Lipangile presented the paper onUse of Bamboo as Water Pipes.

This paper discussed the engineeringcharacteristics, preservation, constructionmethodology, maintenance, and economicsof bamboo used as water pipes. The paperreported, that bamboo pipes are four timescheaper than IocaIIy purchased plastic pipesof the same diameter.

Mr Slob presented his paper on CCAImpregnation of Bamboo.

The paper presented the results of thestudy in which CCA was impregnated intobamboo pipes of the species Arundinariaalpina using the Boucherie process. Highleaching rates of the toxic compounds wereobserved; hence, it was concluded that CCA-treated bamboo is not appropriate for use aswater pipes.

Dr Liese and Dr Higuchi advised theTanzanian delegates (Lipangile and Slob) to“be very careful” in using preservativeson water p ipes as they can endangerhuman Iives and polIute the environment,

Role of Bamboo in Rural Developmentand Socio-economics: A Case Study forThailand was presented by Mr SongkramThammincha. The use of bamboo in thenational economy and on the improvementof the quality of life of the rural poor was out-lined. A cost-benefit analysis of bamboofarming was presented. Destruction of bam-boo in some parts of Thailand is rampant.Efforts should be made to stop this. It was alsosuggested that shoot management be studiedto ensure sustained yield.

Socio-economic Role of Bamboo in Indiaand Their Genetic Diversity was presented by

T A Thomas. The paper indicated the speciespresent in the country, their distribution andsocio-economic role. It pointed out the highgenetic diversity of bamboo in the countrywhere 22 genera and more than 136 speciesare present. It also indicated that bambooresearch on collection and conservation isbeing carried out at FRI, Dehra Dun.

Economics for Forestry Research: SomeSuggested Approaches was presented by CW MacCormac. This paper suggested specifictechniques of economic analysis VIS-A-VISspecific bamboo research and developmentobjectives. The discussion included the fol-lowing.

1. in conducting a benefit-cost analysis, howdo you measure the intangibles?

This is a very important issue. There areno rules available. My suggestion is thatthe scientist should work with an eco-nomist in the estimation of values.

2. Which is more economical, shoot pro-\ duction or culm production?

Research on this is needed.

Concluding Remarks from the ChairmanThe Chairman commended the speakers,

the discussion leaders and the rapporteurs, aswell as the interpreters for doing their jobs well.

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Research Needs and Priorities

Introduction

The information, ideas and conceptsenumerated in the following paragraphs are asummary of the final session of the workshop.There was recognition among participantsthat the present workshop was taking placeafter a period of five years, since the first oneheld in Singapore in May 1980. Though con-siderable effort had gone into activating theresearch agenda that was identified in 1980much needed to be done if the bambooculture, cultivation and utilization is to contri-bute meaningfully to the economies andpeoples of the region.

Information

The major difference between what wasdocumented in Singapore and the presentone was the expression for a bamboo infor-mation centre or service. The bamboo com-munity, be it research, commercial or con-sumer has been growing at a rapid rate. Thepresent flow of information was inadequate tothe needs of the community and therefore anurgent need existed for the establishment ofan information collecting and disseminatingfacility to serve Asia in the first instance andthe rest of the world subsequently.

Conservation

Fears were expressed at the erosion of thegenetic pool not only because of excessiveexploitation especially in the S. Asian regionbut also because of the extensive habitatdestruction in the S. E. Asia region. It is there-fore highly desirable that urgent steps betaken to collect all of the germplasm availablein each region for conservation purposes insitu (through bamboo gardens) or ex situ inspecial ecological reserves.

TaxonomyThe classification, nomenclature and

identification of bamboos still continues to vbea major problem in South and S. E. Asia. Ongoing research work has to be enhanced toexpedite studies in other areas like breedingespecially for increasing yield, disease andpest resistence etc. The need for an Asianbamboo taxonomic monograph still exists andsome initiative should be taken immediatelyto produce this.

Silviculture

Much is known about the ecology andsilviculture of bamboos in some countrieswhile in others little information is available.Especially in the case of the latter, wheresympodial bamboos are concerned, researchneeds were expressed for the followingstudies:

The phenological characteristics of all com-mercially important species. Informationwas especially needed on factors inducingor inhibiting flowering behaviour; theageing of bamboo, physiological mecha-nisms of shooting, etc.

The root characteristics of the principalsympodial species.

Appropriate propagation and nursery tech-nologies to assure large and continuoussupply of seedlings.

Suitable plantation technologies for estab-lishing industrial scale plantations and therisks associated with monocultural situa-t ions.

Options for establishing multicroppingsystems with bamboo as one of the com-ponents.

Options for using bamboo to rehabilitatedevastated lands, control of canal and riverbanks,

The types, level and methods of appli-cation of fertilizers, associated economicsas well as growth studies in man madeplantations.

384

!" Pest and disease situation among bamboostands.

cells (eg. parenchyma, phloem, nodes)and their impact on preservation, season-ing etc.

Management and Harvesting The quality of the culm with referencetheir maturation and/or senescence.

t o

The science of managing bamboos is newto a number of countries and specific prescrip-tions will have to be worked out for eachenvironment. The following studies were con-sidered important on the basis of traditionalpresumption that bamboos have to be workedthrough culm selection:

!

! The chemistry of bamboo and its subse-quent application in chemical utilization(manufacture of plastics, membranes, con-version to fodder, pulping etc) .

Socio-economic studiescultural operations to bamboo stands fromthe time of formation

! clump and culm spacing

. moisture retention techniques

! felling intensities and methods of felling

!" fabrication of improved tools for cutting,splitting and binding bamboos.

The forum expressed a need to undertakecost-benefit studies on bamboo cultivationgiven the fact that land is a scarce resource inthe region and the promotion of bambooforestry should be seen in the context of othercrops.

Further, data has also to be gathered onthe social value of bamboo especially as a fea-ture of water and soil conservation.

UtilizationEducation and Extension

The forum reiterated the need to continueresearch on the topics identified by the 1980workshop, as progress has not been as rapidas expected. Further some of the followingstudies were suggested for inclusion in theagenda:

!" A detailed study on the variability beingencountered in terms of durability withinspecies.

! A closer study on the correlations betweenspecies’ properties and traditional utili-zation.

Unanimously it was pointed out that bam-boo serves multiple uses and therefore inparts of the Asia Pacific region where bamboohas not been recognized for its potential inimproving rural incomes a concerted effortshould be made through the use of demon-stration, plantations, training rural socialworkers with multi-media materials and orga-nizing formal courses within a forestry curri-culum.

!" The functions of the various tissues and G. Dhanarajan

International, Bamboo Workshop (China)October 6-14, 1985

List of Participants

Country Name and AddressBangladesh Dr Eric Boa

Forest Research InstituteP.O. Box 273Chittagong

Canada Mr Jim MullinVice PresidentCollaborative ProgramsDivisionIDRCP.O. Box 8500Ottawa, Ontario, KlG 3H9

China Mr Dong ZhiyongVice-minister

Ministry of Forestry

Mr Wu BoHead of Scientific andTechnical DepartmentChinese Ministry of ForestryBeijing.

Prof Wu ZhonglunThe Chinese Academy ofForestryBeijing,

Prof Hsiung WenyueNanjing Institute of ForestryNanjing, Jiangsu.

Prof. Hou ZhipuVice-president ofthe Chinese Academy ofForestryBeijing.

Mr Yang YuchouVice-head of Foreign AffairDepartmentChinese Ministry of ForestryBeijing.

Mr Xu HansenDeputy Director of AgriculturalDivisionZhejiang Provincial Scienceand Technology CommissionHangzhou, Zhejiang.

Mr Zheng RuiDeputy Director of SecondDivision of Foreign AffairDepartmentChinese Ministry of ForestryBeijing.

Mr Huang WeiguanDeputy Director of ForeignAffair DivisionThe Chinese Academy ofForestryBeijing.Mr Qiu FugengZhejiang Forestry ResearchInsti tuteHangzhou, Zhejiang .

Mr Ma NaixunSubtropical Forestry ResearchInsti tuteThe Chinese Academy ofForestryFuyang, Zhejiang.

Mr Fu MaoyiSubtropical Forestry ResearchInsti tuteThe Chinese Academy ofForestryFuyang, Zhejiang.

Mr Xiao JianghuaSubtropical Forestry ResearchInsti tuteThe Chinese Academy ofForestryFuyang, Zhejiang.

Mr Xu TiansenSubtropical Forestry ResearchInsti tuteThe Chinese Academy ofForestryFuyang, Zhejiang.

Mr Shi QuantaiSubtropical Forestry ResearchInsti tuteThe Chinese Academy ofForestryFuyang. Zhejiang.

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Prof Zhou FangchunNanjing Institute of ForestryNanjing, Jiangsu.

Prof Zhou HuiminNanjing Institute of ForestryNanjing , Jiangsu.

Prof Chen GuishengNanjing Forestry UniversityNanjing. Jiangsu.

Prof Chen ZhiNanjing Institute of ForestryNanjing. Jiangsu.

Mr Zhu JifanNanjing Institute of ForestryNanjing. Jiangsu.

Prof Geng BojieDepartment of BiologyNanjing UniversityNanjing. Jiangsu,

Prof Wang ZhenpingDepartment of BiologyNanjing UniversityNanjing. Jiangsu.

Mr Wen TaihuiZhejiang Forestry ResearchInst i tuteHangzhou, Zhejiang.

Mr Huang PaihuiZhejiang Forestry Research.Inst i tuteHangzhou. Zhejiang.

Mr Hu ChaozongZhejiang Forest CollegeLinan, Zhejiang,

Prof Xue GiruForest Institute of South-WestChinaKunmin, Yunnan, China

Mr Jia LiangzhiPlant Research Instituteof South ChinaGuangzhou, Guangdong.

Mr Li GuoqingBamboo Research SectionHenan Agricultural UniversityZhengzhou, Henan.

Mr Wu BinsenDepartment of ForestryGuizhou Agricultural CollegeGuyiyang, Guizhou.

Mr Wu QixinForestry Institute of GuizhouProvinceGupyang, Guizhou.

Mr Liao GuangluJiangxi Forestry InstituteNanchang, Jiangxi.

Mr Wu MengThe Forestry ResearchInst i tuteof Sichuan ProvinceChengdu, Sichuan.

Mr Yi TongpeiForest School of GuanxianCounty of Sichuan ProvinceGuanxian County, Sichuan.

Mr Sun TianrenAnhui AgriculturaI CollegeHefei, Anhui.

Mr Dai QihuiGuangxi institute of ForestryNanning, Guangxi.

Mrs Zhang GuangchuForest Research Institute ofGuangdong ProvinceGuangzhou, Guangdong.

Mr Liang TairanChinese Ministry of ForestryBeijing.

Mr Chen YoudiResearch Institute of ChemicalProcessing and Utilization ofForest Products,The Chinese Academy ofForestryNanjing, Jiangsu.Mr Zhang ShouhuaiThe Institute of Wood Industry,The Chinese Academy ofForestryBeijing.

Mr Li QihuangSenior EngineerKunmin Designing Institute ofConstructionKunmin, Yunnan.

Mr Luo JianZhejiang Local ProductCompanyHangzhou, Zhejinng

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Germany

Holland

India

Indonesia

Japan

Mrs Liu YurongThe Second Ocean ResearchInstitute, The National OceanBureau of China.Hangzhou.

Mr Sun ChengzhiResearch Institute of ChemicalProcessing and Utilization ofForest Products, The ChineseAcademy of ForestryNanjing. Jiangsu.

Prof Walter LieseInstitute fur HolzbiologieLeuschnerstraBe 9 1D 2050Hambug 80

Dr T. K. LeeJohan Braakensieklaan 192283 GV Ryswyk (Z.H.)

Dr J. J. A. JanssenTechnical University EindhovenPostbus 51356OOMB Eindhoven

Prof Y. M. L. SharmaInternational ForestryConsultant171, VI Gross GandhinagarB a n g a l o r e - 0 0 9

Mr T. A. ThomasHead, Division of Plantationand Project CoordinationBureau of Plant GeneticResourcesIndian Council of AgriculturalResearchKrishi Bhavan, Dr RajendraPrasad RoadNew Delhi 110001

Mr Achmad SulthoniFaculty of ForestryGadjah Mada UniversityBulaksumur, YogyakartaMr Haryanto YudodibrotoFaculty of ForestryGadjah Mada UniversityBulaksumur, Yogyakarta

Dr T HiguchiIUFRO 5.3A Project LeaderWood Research InstituteKyoto UniversityUji, Kyoto

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Malaysia

Nepal

Philippines

Singapore

Sri Lanka

Tanzania

Thailand

Prof E UchimuraForestry and forest ProductsResearch Institute (National)Kukizaki, Ibaraki, 305Prof H Usui AgricultureFaculty of AgricultureUtsunomiya UniversityUtsunomiya 321 UniversityDr Mohd Salleh NorDirectorForest Research InstituteKepong , SeiangorMr C. M. A. StapletonForestry Research Projectc/o British EmbassyP.O. Box 106Kathmandu

Prof Celso B LanticanCollege of ForestryUniversity of the Philippines atLos Banos College, Laguna

Prof A. N. RaoDepartment of BotanyNational University ofSingaporeLower Kent Ridge RoadSingapore 05 11

DrK.VivekanandanForest DeparrmentP.O. Box SO9Colombo 2

Dr T. N. LipangileWood/Bamboo ProjectMinistry of WaterP.O. Box 570Iringa

Mr J. W. SlobWood/Bamboo ProjectMinistry of WaterP.O. Box 570Iringa

Mr Sakomsak RamyarangsiRoyal Forest DepartmentPhaholyothin RoadBangkhen,Bangkok 10900

Mr Songkram ThamminchaFaculty of ForestryKasetsart UniversityBangkok 10903

Dr Anan AnantachoteDepartment of ForestManagementFaculty of ForestryKasetsart UniversityBangkok 10903

Mr Vallobh MaimongkolBanpong Regional ForestryOfficeKailuang Rd. BanpongRatchaburi 70110

IDRC,Singapore

Mr Pongsura TunmaneeBanpong Regional ForestryOfficeKailuang Rd. BanpongRatchaburi 70110

Dr G DhanarajanDeputy Director (Sciences)Off-Campus AcademicProgrammeUniversity Sains MalaysiaMinden, PenangMalaysia

Dr Jingjai HanchanlashRegional DirectorRegional Office for Southeastand East AsiaIDRCTanglin P.O. Box 101Singapore 9 124

Mr Christopher MacCormacProgram OfficerAgricultural Economics

USA

ProgramIDRCTanglin P.O. Box 101Singapore 9 124

MS Maria NgRegional Program OfficerInformation Sciences DivisionIDRCTanglin P.O. Box 101Singapore 9124

Dr Cherla B SastryProgram Officer (Forestry)Agriculture, Food & NutritionSciencesIDRCTanglin P.O. Box 101Singapore 9124.

Dr Julian J. N. CampbellSchool of BioIogicaI SciencesUniversity of KentuckyLexington, Kentucky 40506

Mr Stanley Gibson CooperPanda Products NurseryP.O. Box 70 Calpella CA95418Mr Yat Ying Cheung18 Waverly PIaceSan FranciscoCA 94108,

Mr Timothy James Hansken18 Waverly PlaceSan FranciscoCA 94108,

Post Script

We have spent considerable time and effort in editing the proceedings solving many of the problems and difficultiesconnected therewith. These were mostly concerned in editing the manuscripts. reducing their length. wherever neces-sary or even rewriting some of them which were Gi very poor quality to begin with either in terms of language, expressronor accuracy of facts or all of them. We were completely familiar and anticipated the various problems before we startedthe work. Some of them could be solved by ourselves, whereas in case of others the manuscripts had to be returned tothe authors to implement the necessary correcttons or changes and to provide proper explanations and/or illustrationsObviously all these exchanges delayed the publication We appreciate the patience and endurance of other authors whowould have liked to see or receive the publication much earlier.

The papers included in this proceedings contribute a wealth of information on bamboos that would help the re-searchers and the students who are studying the various aspects of these interesting plants. We hope that t h i s volumelike its predecessor will also serve as an useful source of reference for many years to come.

We are indebted to Mr Kevin Tan for his enormous patience and cooperation in rescheduling the printing pro-gramme of this volume many times. Equally grateful we are to many of our colleagues who helped us in many matters.in one way or the other.

- Editors

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