IRG/WP 11-YYXXX

THE INTERNATIONAL RESEARCH GROUP ON WOOD PROTECTION

Section

VVVVVVVVVV

Resistance to Decay Fungi of Scots PineImpregnated with Natural and Chemical

Preservatives

Sibel YILDIZ, Utku Bulut ŞİMŞEK*

Karadeniz Technical University, Faculty of Forestry, 61080, Trabzon /

TURKEY

* Mersin University Advanced Technologies Research & ApplicationCenter, Department of Nanotechnology and Advanced Materials, 33200

Ciftlikkoy Campus, Mersin, Turkey

Paper prepared for the 45rd Annual MeetingUtah, ABD

11-15 May 2014

DisclaimerThe opinions expressed in this document are

those of the author(s) and are not necessarily

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Resistance to Decay Fungi of Scots Pine Impregnatedwith Natural and Chemical Preservatives

Sibel YILDIZ 1, Utku Bulut ŞİMŞEK 2

1 Karadeniz Technical University, Department of Forest Industry Engineering,61000 Trabzon,Turkey sibelyildiz@ktu.edu.tr

2 Mersin University Advanced Technologies Research & Application Center,Department of Nanotechnology and Advanced Materials, 33200 Ciftlikkoy Campus,

Mersin,Turkey utkubulutsimsek@msn.com

ABSTRACTIn this study, heart-wood and sap-wood specimens of the Scotspine which is naturally grown in Turkey were treated withnatural (valex) and some chemical preservatives such as CCA - C(Copper / Chrome / Arsenic), CBA - A (Copper / Boron /Azole).The wood protective efficacies of these preservativeswere investigated by means of fungi decay test (EN 113).

As a result of the study it was found that the retention valuesof sap-wood samples better than the heart-wood samples. Thehighest percentage retention was obtained from the sap-woodsamples treated with valex 3%, (20,89 kg/m3). Additionally, itwas observed that the chemical preservatives (CCA -C and CBA -

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A) had positive effects on biological test in all variations.But valex especially in low concentration (1%) was exhibitednegative effect for both heart-wood and sap-wood specimens.

Key Words:Impregnation, CCA, CBA,Decay test, Scots pine, Valex

1. INTRODUCTION

Wood is a susceptible material to deterioration by variety oforganisms. If it is used outdoors in areas exposed to dampnessneeds to be protected against wood decay organisms. To extendthe service life of wood different preservatives are used.Chromated copper arsenate (CCA),used as one of the majorpreservatives for many years, has been banned or restricted inmany countries because of the increased public concern on therisk of potential environmental contamination(Temiz et al. 2013).For that reason nowadays it has been studied on newenvironmentally friendly approaches. Some of the new approachescan be summarized as fallows;

- chromium and arsenic-free new formulations (such as CopperAzole)

- plant-based natural preservatives (such as valex)- wood species/types that are naturally resistant to bio-

degradation agents

There are some wood species that are naturally resistant to bio-degradation agents. The resistance is mainly due to theaccumulation of extractives in the heartwood, some of which aredecay inhibitors (Kityo and Plumptre 1997, Syofuna et al. 2012).It is these extractives which render the heartwood unpalatableto wood destroying organisms. Hinterstoisser et al. (2000) notedthat the content of extractives plays a key role in theprediction of the durability of wood. The concentration ofextractives varies among species, between individual trees ofthe same species and within a single tree.There are severaladvantages of using wood extractives as preservatives to enhancethe service life of wood. Barnes (1992) reported thatextractives are organic based protectives produced by nature andmight be easier to detoxify and dispose of without adverseenvironmental effects (Syofuna et all. 2012).

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The aim of this study was to compare theefficacies of natural(valex) and chemical preservatives(CCA and CBA) by means offungi decay test in Scots pine sap-wood and heart-wood samples.

2. EXPERIMENTAL METHODS

2.1. Wood SpeciesThe wood samples were derived from Scots pine (Pinus sylvestries L.)sap-wood and heart-wood.The wood was cut in parallel to graindirections and sawn into specimens measuring 1.5 x 2.5 x 5(radial x tangential x longitudinal) cm long as described in EN113 (1996) standard test method.

2.2. ChemicalsFor the study three different chemicals were selected. As areference chemical; CCA-C (Copper / Chrome / Arsenic), as anatural preservative; valex (the extract of acorn) and newgeneration chemical;CBA-A (Copper / Boron / Arsenate) wereused.Valex (commercial name) was obtained from Valonia oak(Qurcus macrolepis Ky.) produced at the Salihli AR-TU ChemistryPlant in Turkey.The solutions were prepared at1 % and 3 %concentrations, for each heart-wood and sap-wood sample.

2.3. Impregnation MethodThe impregnation procedure was applied according to the ASTM D1413 (1988) standard test method. The samples were impregnatedin a medium scale impregnation container using a vacuum of 635mm of Hg for 40 min followed by 5 atmospheric pressure for 60min. Treated samples were then removed from the treatmentsolution, wiped lightly to remove solution from the woodsurface, and weighed to the nearest 0.01 g to determine grossretentions for each cube and each treating solution. Theretention for each treatment solution was calculated using thefollowing Eq. 2;

R = (G x C/V) x 10    kg/m3  (1)

Where:R: is the retention in kg per cubic meter G: weight in gram of the treating solution absorbed by the samples obtained by subtracting the weight of the samples after

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treatment from the weight of the samples before treatment C: the concentration or solution strength of the treating solution in percentage V: volume of the samples in centimeters

2.4. Decay TestScots pine heart and sap wood samples [1.5x2.5x5 cm (RxTxL)]were exposed to EN 113 standard test containing 4.8 % malt agarextract culture medium against brown rot fungi (Coniophoraputeana). Four replicates for each treatment were used. Theincubation time was 16 weeks at 22 °C and 70 % relative humidity(Figure 1). After incubation, the samples were removed and driedat temperature of 103 ± 2 °C, weighed and the mass loss causedby the fungus calculated as follows (Eq. 2):

Mass loss (%) =  [(mo-md)/mo] × 100 (2)Where:mo is the oven dry mass prior to test and md is the oven dry massafter the test.

Fig 1. Wood samples exposed to fungal attack in a jar for 16 weeks

3. RESULTS AND DISCUSSION

3.1. RetentionThe average retention values of scots pine sap-wood and heart-wood samples were given in Table 1.

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Table 1. Retention results of scots pine sap wood and heart woodsamples (kg/m3)(Standard deviations in parenthesis)

Type of wood samples

Average retention values [kg/m3]

CCA 1% CCA 3% CBA 1% CBA 3% Valex 1% Valex 3%

Sap-wood 7,45(0,38)

19,45(2,53)

6,36(1,22)

18,62(3,26)

4,97(0,96)

20,89(2,46)

Heart-wood 4,04(1,23)

9,00(1,22)

5,17(0,57)

13,17(1,62)

3,87(0,49)

9,76(0,84)

According to the Table 1, it was found that the highestpercentage retention was obtained from the sap-wood samplestreated with valex 3%, (20,89 kg/m3). The second highestperformance was determined from the sapwood samples impregnatedwith CCA 3%, (19,45 kg/m3). As can be seen from the table,retention values of sap-wood samples better than the heart-woodsamples. This result can be seen as normal because of the higherextractive contentin the heart-wood. It has been known thatheart-wood extractives may change the properties of wood. Insome species, they reduce the permeability of the wood tissue,making the heart-wood slower to dry and difficult or impossibleto impregnate with chemical preservatives (Hoadley 2000). Withinthe heart-wood variations,best performance was seen in CBA (3 %)impregnation (13 kg/m3). Retention values increased withincreasing concentration of preservative, in all variations.

3.2. Decay TestDecay resistance of sap-wood and hearth-wood samples treatedwith the preservatives against brown rot fungi (Coniophora puteana)were shown in Table 2.

Table 2. Weight losses (%) of sap-wood andhearth-wood samples treated with differentpreservatives(Standard deviations in parenthesis)

WoodSpecies Chemicals

WeightlossesTest [%]

Weight lossesControl [%]

Sap-wood CCA 1% 0,14(0,04)

22,39(11,51)

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CCA 3 % 0,12(0,09)

18,68(4,93)

CBA 1% 0,15(0,01)

20,12(6,32)

CBA 3% 0,12(0,57)

17,45(5,83)

Valeks 1 %

44,70(19,58)

19,87(4,74)

Valeks 3 %

3,52(1,59)

30,18(17,67)

Hearth-wood

CCA 1% 0,13(0,09)

5,09(2,75)

CCA 3% 0,13(0,08)

8,27(4,43)

CBA 1% 0,14(0,05)

4,67(1,13)

CBA 3% 0,13(0,08)

3,04(2,22)

Valex 1 % 7,52(3,84)

3,77(2,13)

Valex 3 %

3,85(0,88)

6,04(4,12)

Table 2 shows that the best decay performance was achieved inthe CCA and CBA concentrations. Similar results were obtained atdifferent concentrations. Similarly, it was not observed anydifferences between sap-wood and heart-wood samples for CCA andCBA chemicals. The maximum weight loss (44,70%) was obtainedfrom the valex (1%) variation in sap-wood samples. The lowretention ratio supports this result in valex impregnation.Weight loss decreased with increasing the concentration ratio invalex test variations.

Şen (2001) conducted field and laboratory tests of theeffectiveness of some commercially extracts such as valonia oak,gallnut powder, and Pinus brutia barc extracts in 1 %, 3 %, 5, %, 7% and 10 % solutions as antifungal agents on spruce, fir, beechand alder wood blocks. He found that this plant extracts havehigh anti-fungal activity but showed poor fixation in outdoorand laboratory tests. However, concentrations of ≥ 4 % ofcommercial plant extracts showed anti-fungal activity againstwhite-rot (Pleurotus ostreatus) and brown-rot (Phanerochaetechrysosporium), (Şen et al. 2002)

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All test samples had lower weight loss than untreated samples.The weight loss of the control samples was generally higher than20% confirming the validity of the test, especially in sap-woodsamples. But in heart-wood samples weight loss of controlsamples was lower than 20 %. This situation can be attributed tothe amount of extractives present in the heart-wood. It wasreported that the heart-wood of some species, has a differentchemical composition that makes it very durable.Heartwoodiswoodintheinnersectionofalogandisentirelycomposedofdeadcells. This region has a higherconcentration of extractives (phenolic-based compounds) thatmake heart-wood more decay resistant than sap-wood(Shupe et al.2008).

4. CONCLUSION

In this study, it was investigated that the efficacies of somenatural (valex) and chemical preservatives by means of fungidecay test in Scots pine hearth-wood and sap-wood specimens. Asa result it was found that the retention values of sap-woodsamples better than the heart-wood samples. While the highestpercentage retention was obtained from the sap-wood samplestreated with valex 3%, (20,89 kg/m3), the lowest percentageretention was seen in the hearth-wood specimens treated withvalex 1% (3,87 kg/m3) concentration. In all variations,retention values increased with increasing the concentration ofpreservative. As for the fungi resistance, it can be said thatthe chemical preservatives (CCA-C and CBA-A) had positiveeffects on biological test in all variations. But valexespecially in low concentration (1 %) was exhibited negativeeffect for both heart-wood and sap-wood specimens. In this caseit can be suggested that the valex concentration should behigher of 1 %, for a better resistance against brown rot fungidecay.It is also recommended to study the efficacies of theother natural preservatives in different concentrations.

AcknowledgementsThe authors would like to thank Karadeniz Technical University,Department of Forest Industry Engineering Laboratory staff andthat kindly supported the research Prof. Dr. Umit Cafer YILDIZhead of Department of Forest Industry Engineering.

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REFERENCES

ASTM D 1413 (1988): Standard Method of Testing Wood Presertivesby Laboratory Soil-Block Cultures. D. 1413-76. In: Annual Bookof ASTM Standards, Vol. 4.09 Wood, Philadelphia, PA, p. 239-245.

Barnes, H.M. 1992. Wood Protecting Chemicals from the 21st

century. International Research Group on wood preservation, 24th

Annual Conference Meeting at Orlando, Florida, USA, 16-20 May1992, IRG/WP 93-30018. 29 p      

EN 113 (1996): Wood preservatives-Test method for determiningthe protective effectiveness against wood destroyingbasidiomycetes-Determination of the toxic values.

Hinterstoisser, B. Stefke, B, Schwanninger, M(2000): Wood: Rawmaterial- material-Source of Energy for the future.Lignovisionen,2: 29-36.

Hoadley, R B(2000): Understanding Wood. The Nature of Wood andits Properties. Chapter:1, 7-16. The Taunton Press, USA.

Kityo, P. W, Plumptre, R A(1997):The Uganda Timbers users Handbook. Aguide to better timber use. Common Wealth Secretariat. London.31p.

Shupe, T, Lebow, S, Ring, D (2008): Causes and control of wooddecay, degradation & stain. Louisiana State UniversityAgricultural Center, 26 pages.

Simsek, U B (2013): Some Physical and Biological Properties ofScots Pine Treated with Natural and Chemical Preservatives, Msc.Thesis, Karadeniz Technical Universtiy, Institue of Science,Thesis Applied Number: 348391, Trabzon, Turkey

Syofuna, A, Banana, A Y, Nakabonge, G (2012): Efficiency ofnatural wood extractives as wood preservatives against termiteattack. Maderas. Ciencia y tecnología,14(2):155-163.

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Şen, S (2001): Determination of wood preservative activities ofplant phenolics. Ph.D. Thesis. ZKÜ, Graduate school of natural and applied sciences. Departmentof Forestry Industrial Engineering, p. 300, Bartın, Turkey

Şen, S, Hafızoğlu, H, Dığrak, M (2002): Investigation of woodpreservative activities of plant extracts and tannins asfungicide. KSU Journal of Science and Engineering5, 99-110. Temiz, A, AlfredsenG, Yildiz, U C,   Gezer, E D, Kose, G,AkbasS, Yildiz, S (2013): Leaching and decay resistance of alderand pine wood treated with copper based wood preservatives.Maderas. Ciencia y tecnología, In press. 

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