Research Article Tree Species Richness, Diversity, and ...

Research ArticleTree Species Richness Diversity and VegetationIndex for Federal Capital Territory Abuja Nigeria

Aladesanmi D Agbelade1 Jonathan C Onyekwelu2 and Matthew B Oyun2

1Department of Forest Resources and Wildlife Management Faculty of Agricultural SciencesEkiti State University PMB 5363 Ado Ekiti Ekiti State Nigeria2Department of Forestry and Wood Technology School of Agriculture and Agricultural TechnologyFederal University of Technology PMB 704 Akure Ondo State Nigeria

Correspondence should be addressed to Aladesanmi D Agbelade aladesanmi2008gmailcom

Received 3 August 2016 Revised 13 November 2016 Accepted 28 November 2016 Published 31 January 2017

Academic Editor Piermaria Corona

Copyright copy 2017 Aladesanmi D Agbelade et alThis is an open access article distributed under the Creative CommonsAttributionLicense which permits unrestricted use distribution and reproduction in anymedium provided the originalwork is properly cited

This study was conducted to investigate the tree species richness and diversity of urban and periurban areas of the Federal CapitalTerritory (FCT) Abuja Nigeria and produceNormalizedDifferenceVegetation Index (NDVI) for the territory Datawere collectedfrom urban (Abuja city) and periurban (Lugbe) areas of the FCT using both semistructured questionnaire and inventory of treespecies within green areas In the study location all trees with diameter at breast height (dbh) ge 10 cmwere identified their dbh wasmeasured and frequency was taken The NDVI was calculated in ArcGIS 103 environment using standard formula A cumulativetotal of twenty-nine (29) families were encountered within the FCT with 27 occurring in Abuja city (urban centre) and 12 in Lugbe(periurban centre) of the FCT The results of Shannon-Wiener diversity index (1198671015840) for the two centres are 356 and 224 whileShannonrsquos maximum diversity index (119867max) is 654 (Abuja city) and 536 (Lugbe) for the urban (Abuja city) and periurban (Lugbe)areas of the Federal Capital Territory (FCT) The result of tree species evenness (Shannonrsquos equitability (119864119867) index) in urban andperiurban centres was 054 and 042 respectively The study provided baseline information on urban and periurban forests in theFCT of Nigeria which can be used for the development of tree species database of the territory

1 Introduction

Urban forests are made up of the trees shrubs and othervegetative covers that play important role in human lifeUrban forests serve important roles such as tree speciesdiversity conservation and protection of fragile ecosystemdevelopment of parks and event centres for relaxation andsocial engagements provision of vegetable and fruitsseedsfor foods and medicines and purification of air windbreak and beautification of the environment [1] Researchin developing countries has revealed that trees are plantedaround houses for fruits nuts leaves fuelwood foddervegetables shade and windbreaks [2] In traditional Africansettlements it is usually common to plant trees in villagesquares to provide shade for social meetings ceremoniesrecreation and religious worships The growing urban pop-ulation in Nigeria is redefining urban forestry practices

and has presented new challenges and opportunities forresearchers

Urbanization in developing countries is on the increaseand this has resulted in social burden in the urban cities dueto their limited capacity to adapt to socioeconomic challengesof the new environments [3] Global projections indicatethat future trends in urbanization could triple between2000 and 2030 [4ndash7] According to 2011 revision of WorldUrbanization Prospects the urban areas of the world isexpected to gain 14 billion people between 2011 and 203037 of which will come from China (276 million) and India(218 million) The report predicts that between 2030 and2050 another 13 billion people will be added to the globalurban populationWith a total addition of 121 million peopleNigeria will be the second major contributor next to India(270 million) [8] The negative effect of urban expansionincludes threat to ecosystem biodiversity and carbon emis-

HindawiInternational Journal of Forestry ResearchVolume 2017 Article ID 4549756 12 pageshttpsdoiorg10115520174549756

2 International Journal of Forestry Research

sions due to tropical deforestation and expansion of socialinfrastructure [9]

The increasing population of Abuja city Nigeriarsquos FederalCapital Territory (FCT) has led to a wide range of challengeswhich has now put lots of pressure on land forest and forestresources and green spaces and exposed the city to differentenvironmental hazards Environmental hazards such as airpollution wind and water erosion are on the increase asa result of deforestation and population increase withinthe FCT and this is evident in different parts of Nigeriacities [2 10] In our growing urbanized environments themaintenance and development of urban vegetated areas areamong the challenges of sustainable urban planning [2 11]

Research has suggested that urban forest and urban greenareas could be another effectivemeans of biodiversity conser-vation and ecosystems potentials in terms of physiologicalsociological economic and aesthetic benefits [12] Urbanforests could also be used to reduce the challenges posedby urbanization such as food insecurity energy shortagedeteriorating air quality high temperatures health hazardsand increased noise levels [2] Other benefits derived fromurban forests include healthy environment which translatesto healthy citizens beautification of the environment andscenery cooler air temperature reductions in ultraviolet radi-ation and social and ecological benefits [9 11 13] This studyinvestigates tree species richness diversity and vegetationindex for Federal Capital Territory Abuja Nigeria

2 Methodology

21 Location of Study Area The study was conducted inAbuja the Federal Capital Territory (FCT) of Nigeria Thecity lies between latitude and 9∘031015840 and 9∘071015840N and longitude7∘261015840 and 7∘391015840E in the North central region of NigeriaAbuja experiences tropical wet and dry climate The FCTexperiences a warm humid rainy season and a blistering dryseason (harmattan) occasioned by the northeast trade windwith the main features of dust haze intensified coldness anddryness Rainfall in the FCT reflects the territoryrsquos locationon the windward side of the Jos Plateau and the zone ofrising air masses Balogun [14] opined that due to the hillyand mountainous nature of Abuja city orographic activitiesbring heavy and frequent rainfall during the rainy seasonThe rainy season begins in March and ends in Novemberwith peak in September during which abundant rainfall isreceivedMean annual rainfall inAbuja ranges from 1000mmto 1600mm Mean monthly temperature ranges between258∘C and 302∘C [14 15] The soils of the study area arebasically Alluvial and Luvisols which supports growth of treespecies such as Khaya spp Parkia biglobosa Delonix regiaEucalyptus spp Azadirachta indica and Gmelina arborea[16]

Lugbe is one of the popular suburban settlements inAbuja It is in the Abuja Municipal Area Council (AMAC)It is largely residential and densely populated Lugbe is about17 minutesrsquo drive from the Central Business District of Abujaand 13 minutesrsquo drive to the Abuja Airport Though Lugbeis not in the Federal Capital City (FCC) its proximity to thecity centre and also to the Abuja Airport has brought it into

lime light and attracted significant development to the areaThe area is developing very fast and it houses the NationalSpace Development and Research Agency Federal HousingAuthority (FHA) Estate and Voice of Nigeria TransmissionStation

3 Data Collection

The city of Abuja was purposefully selected as the urbansector for this research based on its high infrastructural devel-opment population density and its economic importance inNigeriawhile the closest satellite town (Lugbe)was selected asthe periurban settlement Both semistructured questionnaireand biodiversity assessment were used for data collectionThe questionnaire was used to obtain information on thesocioeconomic and environmental benefits of urban forestTwenty respondents were purposefully selected in each urbanand periurban centre of the FCT which translated to a totalof forty (40) questionnaires for this study Administration ofquestionnaires was done using snowball sampling respon-dents were those who own tree(s) or who have association(s)with tree(s) This was supported by earlier study by [11]which used snowball sampling methods due to the pecu-liarity of urban forest development in Ibadan metropolisThese questionnaires were administered in form of interviewguide such that respondents were requested to complete andreturn them immediately thus resulting in 100 retrievalThe study covers 20 of Abuja Federal Capital Territory(FCT) built-up centres The biodiversity assessment entailscomplete enumeration of tree species in public parksgardenprivate gardenshome gardens avenueroadside trees schoolgrounds public and private institutions and any spacewith conglomerates of trees Within the selected urban andperiurban centre all trees with diameter at breast height(dbh)ge 10 cmwere identified their diameters at breast heightdiameters at the base middle and top and total height weremeasured while their frequencies were taken All tree speciesin each city were assigned to families using Keay [17] as guide

4 Data Processing and Analysis

41 Computation of Normalized Difference Vegetation Index(NDVI) Normalized Difference Vegetation Index (NDVI)is one of the most widely used vegetation indices which isapplicable in satellite analysis and monitoring of vegetationcover [18 19] In this study the NDVI was calculated inArcGIS 103 environment using

NDVI = NIR minus VISNIR + VIS (1)

whereNDVI isNormalizedDifferenceVegetation IndexNIRis near infrared and VIS is visible red reflectance

The value of the pixels varies between minus1 and +1 thehigher the value of NDVI the richer and healthier thevegetation cover of such environment

42 Computation of Growth Parameters and BiodiversityIndices Thecomputations of the following growth parameterand biodiversity indices were undertaken

International Journal of Forestry Research 3

421 Basal Area The basal area of all trees in this study areawas calculated using

BA = 1205871198632

4 (2)

where BA is basal area (m2) 119863 is diameter at breast height(cm) and 120587 is pie (3142) The total BA for the city wasobtained by adding all trees BA in the city

422 Volume Volume of individual trees was estimatedusing tree volume equation developed Newtonrsquos formula asfollows [20]

119881 = 120587ℎ1198631198872 + 4 (1198631198982) +119863119905224 (3)

where 119881 is tree volume (m3) 119863119887 119863119898 and 119863119905 are diameters(m) at the base middle and top of each tree and ℎ is totaltree height (m)

423 Species Relative Density (RD) Species relative densitywhich is an index for assessing species relative distribution[21] was computed with

RD = ( 119899119894119873) times 100 (4)

where RD () is species relative density 119899119894 is the numberof individuals of species 119894 and 119873 is the total number of allindividual trees of all species in the entire community

424 Species Relative Dominance (RD119900) Species RelativeDominance (RD119900 ()) used in assessing relative spaceoccupancy of a tree was estimated using [22]

RD119900 = (sumBa119894 times 100)sumBa119899 (5)

where Ba119894 is basal area of all trees belonging to a particularspecies 119894 and Ba119899 is basal area of all trees in a city

425 Importance Value Index (IVI) The Importance ValueIndex (IVI) of each species was computed with the relation-ship in the following equation [21]

IVI = (RD + RD119900)2 (6)

426 Species Diversity Index Species diversity index (1198671015840)was computed using the Shannon-Wiener diversity index inthe following equation [23 24]

1198671015840 = minus119904

sum119894=1

119875119894 ln (119875119894) (7)

where 1198671015840 is Shannon-Wiener diversity index 119904 is the totalnumber of species in the community 119875119894 is the proportion ofSmade up of the ith species and ln is natural logarithm

427 Shannonrsquos Maximum Diversity Index Shannonrsquos maxi-mum diversity index was calculated using [24]

119867max = ln (119878) (8)

where 119867max is Shannonrsquos maximum diversity index and 119878 isthe total number of species in the community

428 Species Evenness Species evenness in each city wasdetermined using Shannonrsquos equitability (119864119867) which wasobtained using [23]

119864119867 = 1198671015840

119867max= minussum

119904119894=1 119875119894 ln (119875119894)ln (119878) (9)

429 Sorensenrsquos Species Similarity Index Sorensenrsquos speciessimilarity index between two cities was calculated using [2526]

SI = ( 2119862119886 + 119887) times 100 (10)

where119862 is the number of species in sites 119886 and 119887 and 119886 and 119887= number of species at sites 1 and 2 respectively

43 Data Analyses After retrieval the questionnaires werecoded to obtain quantitative values for statistical analysisDescriptive analysis was used to summarise the data whilecorrelation analysis was used to investigate the relationshipsbetween some biodiversity indices and growth variablesStudentrsquos t-test was used to test for significant difference in thegrowth variables of individual trees in urban and periurbanareas for the study All statistical analyses were undertakenusing Statistical Package for Social Sciences (SPSS 200)software package Normalized Difference Vegetation Indexof the entire city was calculated and analysed in ArcGIS 103environment to determine the level of greenness of the citybetween 2000 and 2015

5 Results

51 Biodiversity Indices and Growth Variables A cumulativetotal of twenty-nine (29) families were encountered withinthe FCT with 27 occurring in Abuja city (ie urban centre)and 12 in Lugbe (ie periurban centre) of the FCT (Table 1)Within the urban and periurban areas families with highnumber of tree species include Fabaceae Moraceae Euphor-biaceae Combretaceae Arecaceae and Myrtaceae A pooledtotal of 69 in Abuja city and 20 in Lugbe were identifiedwithin the FCT Numbers of tree species were higher in theurban centre (Abuja city) than in the periurban area (Lugbe)(Table 1) The results of Studentrsquos t-test showed that bothnumber of family and tree species were significantly higherin the urban area than the periurban area of the FCT Basedon the results of tree growth parameters the trees in theurban area were larger than those in the periurban areaResults in Table 1 show that mean dbh (593 cm) basal area(5103m2) volume (7528m3) and maximum dbh (2123 cm)of tree in Abuja city (urban area) were significantly higherthan the values recorded for the corresponding parameters


Table 1 Summary result of biodiversity indices and growth param-eters for tree species in urban and periurban areas of FCT

Benefits derived Federal Capital Territory (FCT)Urban forest Periurban forest

Number of individual trees 695a 213b

Number of species 69a 20b

Number of families 27a 12b

Mean Dbh (cm) 593a 162b

Basal area (m2) 5103a 1370b

Maximum Dbh (cm) 2123a 1907b

Volume (m3) 7528a 191b

Diversity index (1198671015840) 356a 224b

Max diversity (119867max) 654a 536b

Species evenness (119864119867) 054a 042a

Values followed by similar letters are not significantly different (119901 gt 005)

in Lugbe (periurban area) Also the frequency of occurrenceof individual trees in urban area of Abuja was significantlyhigher than that of the periurban centre of the city

The results of Shannon-Wiener diversity index (1198671015840) forthe two centres are 356 and 224 while Shannonrsquos maximumdiversity index (119867max) is 654 (Abuja city) and 536 (Lugbe)for the urban (Abuja city) and periurban (Lugbe) areas ofthe Federal Capital Territory (FCT)The result of tree speciesevenness (Shannonrsquos equitability (119864119867) index) in urban andperiurban centres was 054 and 042 respectively

The result also revealed that the species relative density(RD) for individual trees in the urban and periurban centresof the FCT ranged from 014 to 1041 in Abuja city andfrom 047 to 3380 Lugbe (Tables 2 and 3) Tree specieswith high relative density (RD) in Lugbe were Gmelinaarborea Parkia biglobosa and Mangifera indica accountingfor 3380 1221 and 939 respectively while in Abujacity Gmelina arborea (1040) Terminalia ivorensis (607)and Delonix regia (535) had high relative density SpeciesRelative Dominance (RD119900) varied from 004 to 694 inAbuja city and from 015 to 2085 in Lugbe Within theurban areas (Abuja city) tree species with high RelativeDominance (RD119900) were Spathodea campanulata (694)Nauclea latifolia (568) and Azadirachta indica (560)while in the periurban areas (Lugbe) of the FCTAzadirachtaindica (2085) Ricinodendron heudelotii (1677) andNau-clea diderrichii (1059) dominated Tree species with highImportance Value Index were Gmelina arborea (582)Azadirachta indica (396) and Khaya senegalensis (374)in Abuja city while Azadirachta indica (1418) Parkia biglo-bosa (1009) and Ricinodendron heudelotii (862) werespecies with high importance in the floristic composition ofLugbe (Tables 2 and 3)

52 Benefits Derived from Urban Forests Urban forest ben-efits are numerous important and beneficial to humanlivelihood reduce health related problems and contribute tothe amelioration of both micro- and macroclimates Table 4indicates that people are aware of the various benefits derived

from urban forest The majority of respondents (70) inLugbe (periurban area) and Abuja (urban area) opined thatthey derive fresh air from trees around them A muchhigher percentage (85) of respondents in the periurban areaderived fuelwood for their cooking purposes from urbanforest when compared to the 10 of respondents in urbanarea who indicated that they sourced fuelwood from urbanforests About 50 and 65 of the respondents in urbanand periurban centres respectively derived edible fruits fromtrees around them Between 40 and 50 of the respondentsin urban and periurban centres of the FCT indicated that theyderived vegetables from trees around them which they usedfor their diet High percentage (60 to 75) of respondents inboth urban and periurban centres use tree as windbreak toprotect their buildings and other structures The percentageof respondents who use trees for shade for the purpose ofsocial gathering in both urban (Abuja 60) and periurbanareas (Lugbe 75) is relatively high which is similar tothe percentage of those who use urban forest facilities forrelaxationgardenbarjoint purposes (70 to 60) (Table 4)About 40 and 50 of the respondents in Abuja city andLugbe respectively make use of different parts of treesaround them for medicines for curing different diseases(Table 4)

6 Relationship between TreeGrowth Variables

Generally there was positive and significant linear relation-ship between tree growth variables in both urban (Abujacity) and periurban (Lugbe) areas of the FCT (Tables 5 and6) The correlation coefficient ranged from 016 to 096 inthe periurban area (Lugbe) and from 026 to 097 in theurban area (Abuja city) The highest correlation coefficientwas obtained between logarithmic transformed basal areaand logarithmic transformed volume for trees in Lugbe(periurban area) while it was between height and basalarea as well between logarithmic transformed basal areaand logarithmic transformed volume for trees in Abuja city(urban area) Very weak correlation was observed betweenheight and basal area (016) height and diameter (018 026)and diameter and basal area (029) for urban and periurbancentres in the FCT

7 Results of Thematic MapProduction and Green Area Indexof Federal Capital Territory

The thematic maps of the Federal Capita Territory (FCT)were produced from its satellite imagery using ArcGIS 103which led to the generation of Normalized Difference Vege-tation Index of the city for the years 2000 and 2015 (Figures1(a) and 1(b)) Apart from the boundary of each FCT thelocations visited for data collected and NDVI were shown inthe maps The boundary was digitized to determine the sizeof the FCT which was georeferenced with the attribute datacollected from the field The maps produced in this researchreflected the level of flexibility of GIS in creating calculating


Table 2 Biodiversity indices and growth parameters of individual trees in the urban areas (Abuja city) of the Federal Capital TerritoryNigeria

SN Tree species Family FQ MHt MDbh BA Vol RD RD119874 IVI1 Adansonia digitata Bombacaceae 3 42 510 184 772 043 360 2022 Albizia falcata Fabaceae 1 198 160 002 040 014 004 0093 Albizia ferruginea Fabaceae 1 170 1380 150 2543 014 293 1544 Alstonia boonei Apocynaceae 1 146 864 059 856 014 115 0655 Anacardium occidentale Anacardiaceae 1 188 320 008 151 014 016 0156 Anogeissus leiocarpa Combretaceae 2 171 841 222 3796 029 435 2327 Azadirachta indica Meliaceae 16 191 119 286 5456 231 560 3968 Bambusa vulgaris Poaceae 3 166 128 012 193 043 023 0339 Bauhinia monandra Fabaceae 5 127 117 027 344 072 053 06310 Bauhinia polyantha Leguminosae 1 185 1050 087 1602 014 170 09211 Blighia sapida Sapindaceae 1 134 650 033 445 014 065 04012 Bosqueia angolensis Moraceae 24 188 32 046 866 347 090 21913 Caesalpinia pulcherrima Fabaceae 3 117 60 003 030 043 005 02414 Calliandra calothyrsus Leguminosae 7 86 83 026 226 101 052 07615 Callitris intratropica Cupressaceae 1 168 1120 099 1655 014 193 10416 Cassia pleurocarpa Caesalpiniaceae 7 84 46 008 069 101 016 05917 Casuarina equisetifolia Casuarinaceae 11 108 66 041 441 159 080 11918 Ceiba pentandra Bombacaceae 6 95 216 131 1248 087 257 17219 Citrus aurantifolia Rutaceae 9 142 79 039 561 130 077 10420 Cleistopholis patens Annonaceae 5 156 174 059 927 072 117 09421 Cocos nucifera Arecaceae 11 84 53 026 222 159 052 10522 Cola gigantean Malvaceae 1 158 1090 093 1475 014 183 09923 Corymbia citriodora Myrtaceae 1 134 360 010 136 014 020 01724 Dacryodes edulis Burseraceae 1 126 748 044 554 014 086 05025 Daniellia oliveri Leguminosae 20 128 72 162 2070 289 317 30326 Delonix regia Fabaceae 37 142 12 017 238 535 033 28427 Drypetis spp Nymphalidae 4 150 231 067 1006 058 131 09528 Elaeis guineensis Arecaceae 1 142 478 018 255 014 035 02529 Eucalyptus camaldulensis Myrtaceae 1 110 420 014 152 014 027 02130 Eucalyptus citriodora Myrtaceae 32 176 43 146 2565 462 286 37431 Eucalyptus forrestiana Myrtaceae 10 110 42 014 150 145 027 08632 Euphorbia dendroides Euphorbiaceae 1 80 520 021 170 014 042 02833 Ficus goliath Moraceae 14 155 50 038 593 202 075 13934 Gmelina arborea Verbenaceae 72 140 12 063 883 1040 124 58235 Hildegardia baterii Malvaceae 1 157 896 063 990 014 124 06936 Hura crepitans Euphorbiaceae 8 116 108 058 674 116 114 11537 Jatropha curcas Euphorbiaceae 1 40 160 002 008 014 004 00938 Khaya senegalensis Meliaceae 32 176 43 146 2565 462 286 37439 Lophira alata Ochnaceae 1 152 1150 104 1579 014 204 10940 Lophira procera Ochnaceae 3 123 154 017 207 043 033 03841 Mangifera indica Anacardiaceae 20 111 21 013 148 289 026 15842 Milicia excelsa Moraceae 2 196 575 104 2036 029 204 11643 Milicia regia Moraceae 1 144 901 064 918 014 125 07044 Millettia thonningii Fabaceae 5 135 145 041 559 072 081 07745 Morinda lucida Rubiaceae 1 148 688 037 550 014 073 04446 Moringa oleifera Moringaceae 2 170 165 009 145 029 017 02347 Nauclea diderrichii Rubiaceae 2 155 680 145 2249 029 284 15748 Nauclea latifolia Rubiaceae 2 143 961 290 4145 029 568 29949 Parkia biglobosa Fabaceae 26 163 45 109 1780 376 214 29550 Pueraria phaseoloides Leguminosae 1 135 1320 137 1848 014 268 141


Table 2 Continued

SN Tree species Family FQ MHt MDbh BA Vol RD RD119874 IVI51 Pinus caribaea Pinaceae 7 119 80 025 295 101 049 07552 Pinus caribaea Pinaceae 6 71 147 061 436 087 120 10453 Plumeria alba Apocynaceae 19 121 37 039 478 275 077 17654 Polyalthia longifolia Annonaceae 31 132 25 048 632 448 094 27155 Psidium guajava Myrtaceae 3 194 142 014 277 043 028 03656 Ravenala madagascariensis Strelitziaceae 1 154 360 010 157 014 020 01757 Ricinodendron heudelotii Euphorbiaceae 1 68 1710 230 1562 014 450 23258 Roystonea dunlapiana Arecaceae 24 166 56 140 2331 347 275 31159 Roystonea regia Arecaceae 21 178 38 049 879 303 097 20060 Senna siamea Fabaceae 6 212 148 062 1313 087 121 10461 Spathodea campanulata Bignoniaceae 1 222 2123 354 7860 014 694 35462 Tectona grandis Lamiaceae 11 160 107 109 1750 159 214 18763 Terminalia catappa Combretaceae 37 79 07 005 037 535 009 27264 Terminalia ivorensis Combretaceae 42 91 07 008 070 607 015 31165 Terminalia macroptera Combretaceae 31 116 35 092 1071 448 181 31466 Terminalia superba Combretaceae 9 127 136 117 1485 130 229 18067 Treculia africana Moraceae 1 60 858 058 347 014 113 06468 Vachellia nilotica Fabaceae 17 92 36 030 274 246 058 15269 Vitex doniana Verbenaceae 2 164 425 057 931 029 111 070

692 5102 75275FQ number of tree stems in the city BA basal area of trees in the city Vol volume of trees in the city

Table 3 Biodiversity indices and growth parameters of individual trees in the periurban areas (Abuja city) of the Federal Capital TerritoryNigeria

SN Tree species Family FQ MHt MDbh BA Vol RD RD119874 IVI1 Albizia falcate Fabaceae 1 198 160 002 040 047 015 0312 Azadirachta indica Meliaceae 16 191 119 286 5456 751 2085 14183 Cleistopholis patens Annonaceae 5 156 174 059 927 235 434 3344 Cocos nucifera Arecaceae 11 84 53 026 222 516 193 3555 Delonix regia Fabaceae 17 142 27 017 238 798 122 4606 Elaeis guineensis Arecaceae 1 142 478 018 255 047 131 0897 Euphorbia dendroides Euphorbiaceae 1 80 520 021 170 047 155 1018 Ficus goliath Moraceae 4 155 175 038 593 188 279 2349 Gmelina arborea Verbenaceae 72 140 12 063 883 3380 460 192010 Hildegardia baterii Malvaceae 1 157 896 063 990 047 460 25411 Jatropha curcas Euphorbiaceae 1 40 160 002 008 047 015 03112 Mangifera indica Anacardiaceae 20 111 21 013 148 939 097 51813 Nauclea diderrichii Rubiaceae 2 155 680 145 2249 094 1059 57614 Parkia biglobosa Fabaceae 26 163 45 109 1780 1221 797 100915 Ravenala madagascariensis Strelitziaceae 1 154 360 010 157 047 074 06116 Ricinodendron heudelotii Euphorbiaceae 1 68 1710 230 1562 047 1677 86217 Senna siamea Fabaceae 6 212 148 062 1313 282 452 36718 Terminalia superba Combretaceae 9 127 136 117 1485 423 853 63819 Treculia Africana Moraceae 1 60 858 058 347 047 422 23520 Vachellia nilotica Fabaceae 17 92 36 030 274 798 218 508



7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

Selected areas

NDVI valueHigh 0326541

Low minus00765043

N

0 175 35 7 105 14

(Kilometers)

(a)

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

Selected areas

NDVI value

N

High 00416667

Low minus046789

0 175 35 7 105 14

(Kilometers)

(b)

Figure 1 (a) Normalized Difference Vegetation Index (NDVI) map for Abuja for the year 2000 and sampling locations (b) NormalizedDifference Vegetation Index (NDVI) map for Abuja for the year 2015 and sampling locations

and manipulating different research data for productionof different maps Normalized Difference Vegetation Index(NDVI) values of the city were calculated in ArcGIS 103environment to determine the level of greenness of the city

The NDVI value (0327) for 2000 was relatively low butmoderate There was drastic reduction in the NDVI value(0042) for 2015 which may be an indication of reductionand scattering in the vegetative cover of the FCT as a result


Table 4 Benefits derived by respondents () from urban andperiurban forests in the Federal Capital Territory Nigeria

Benefits derived Abuja (FCT)Urban area ()lowast Periurban area ()lowast

Medicine (herbs) 40 50Relaxationgarden 70 60Animal fodder 15 50Fuel wood (cooking) 10 85Shade (meetings) 65 70Vegetable (soup) 50 40Fresh air 70 70Beautification 90 50Edible fruits (food) 50 65Windbreak 60 75lowastRespondents were allowed to choose more than one option (ie multipleresponses)

of infrastructural development and population increase Thelow value of NDVI in year 2015 has greater effects on theLand Surface Temperature (LST) and climate change of thecity The lower the NDVI value the higher the LST whichtend to expose the city to more higher temperature and theclimate change on the populace Increase in NDVI value andreduction in LST value will create conducive environment forincrease in tree diversity and green space coverage

8 Discussion

81 Biodiversity Indices and Tree Growth Yield VariablesForest ecosystems are pivotal to the functioning and con-serving of biosphere as they are the origin of many plantsand animals [27] The urban forests include trees plantedalong streets compounds school gardens parks riverbankscity cemeteries city vacant lots adjacent wood land andanywhere else where trees grow in urban areas [28 29]Urban forests are among the in situ conservation methodsthat are essential in protecting and conserving tree species forthe greatest benefits of the society The results of this studyconfirmed that urban forest is a repository of many indige-nous tropical hardwood and exotic tree species in differentfamilies judging by the tree species richness of Abuja citywhich is similar to or higher than what has been reportedin some natural forest ecosystems in Nigeria [30ndash33] Forexample [30 31] reported 31 and 51 trees species in tropicalrainforest ecosystems of southwestern Nigeria A total of 5655 and 54 tree species were found in Sapoba Shasha andAla forest reserves in Nigeria respectively [32 33] Thus thelarge numbers of tree species that are found in tropical forests[30 31] could also be said to be characteristics of urbanforest landscapes This similarity of tree species richness ofurban centres and natural forest ecosystems underscores theimportance of urban forests in biodiversity conservation andthus is evidence that urban forests can be both reservoirs andcontributor to global biodiversity conservation

Biodiversity indices of urban and periurban forests aregenerated in order to appreciate the level of diversity andabundance of species in built-up environment IIRS [34]noted that biodiversity indices are generated to bring thediversity and abundance of species in different habitats tosimilar scale for comparison and the higher the value thegreater the species richness

Konijnenddijk et al [35] had noted that the levels ofbiodiversity in urban and periurban areas are often surpris-ingly high even when compared with forest trees diversityThe Shannon-Wiener diversity and Evenness indices of thisstudy are higher than the values of Parthasarathy [36] andYang et al [37] In another study Duran et al [38] obtainedShannon-Wiener diversity index range of between 269 and333 which is within the range of the values reported forurban and periurban areas of FCT in this studyThe Shannon-Wiener diversity index of Abuja city (ie urban area) in thestudy is within the range of the values reported for somenatural tropical forest ecosystems [30 31 33] as well as thevalues obtained by Agbelade et al [11] for urban forestsin Ibadan southwestern Nigeria However the Shannon-Wiener diversity index of Lugbe (ie periurban area) is lowerthan the values reported by the studies mentioned aboveTheimplication of this is that urban centres have higher speciesdiversity than periurban areas which is further confirmedby the higher species richness in Abuja city (urban area)compared to that of Lugbe (periurban area)

Though Alvey [39] reported that traditionally urban for-est areas have been regarded as locations of low biodiversitythat are dominated by nonnative species evidence from thisstudy as well as those from published information is mount-ing that urban and suburban areas can contain relatively highlevels of biodiversity [40ndash42] Contrary to the conclusion ofAlvey [39] there are indications from the results of this studythat urban and periurban forests have good store of bothnative and nonnative species However a higher percentageof the very common species are exotic species Our resultsshowed that Azadirachta indica Eucalyptus species Acaciaspecies and Gmelina arborea are the four most commonspecies in Abuja which is in agreement with the earlier studyof Fuwape and Onyekwelu [2] Three of these four mostcommon species are exotic species The tree planting andlandscaping mechanism in Abuja may be responsible for thehigh level of tree species diversity encountered in it Theinfrastructural development in Abuja city had low impact onthe level of tree species diversity which could be attributed tothe careful planning managing and planting of trees Thusit could be concluded that infrastructural development inAbuja city did not negatively affect the extent of biodiversityin it This could imply that landscaping of the city wasconsidered alongside with the infrastructural developmentThe spatial arrangement of trees as well as the choice andcombination of tree species clearly distinguishes Abuja asa well-landscaped city Nowak and Walton [43] noted thatexpanding urbanization increases the importance of urbanforests in terms of their extent and the critical ecosystemservices they provide to sustain human health and environ-mental quality in and around urban areas In Guangzhoucity China Jim and Liu [44] found over 250 plant species


Table 5 Correlation coefficients for tree growth variables in periurban area (Lugbe)

Height Diameter Basal area (BA) Volume (Vol) Ln BA Ln VolHeight 100Diameter 18 100Basal area (BA) 16 96 100Volume (Vol) 41 86 90 100Ln BA 17 93 81 71 100Ln Vol 44 88 76 74 96 100

Table 6 Correlation coefficients for tree growth variables in urban area (FCT Abuja)


after surveying over 115000 plants in the parks on universitygrounds and along streets This affirmed that there arerelatively high numbers of stems found in urban centrewhich could be higher than the number in conservationcentres Araujo [45] also asserted that human actions directlyor indirectly increase the total number of species throughintroduced species and increase in landscape heterogeneity

82 Benefits Derived from Urban and Periurban Forests Treespecies encountered in urban and periurban centres of theFederal Capital Territory Abuja are used for food (eg ediblefruitsseeds vegetables) nutrition supplement medicinalsubstances fuelwood and animal fodder Onyekwelu andOlaniyi [10] had observed that urban forestry practicesimprove food security of poor urban inhabitants throughcollection of wild edible plants as vegetable planting of low-care fruit bearing trees including a gardening componentin multifunctional parks or creating edible public parksThere are environmental benefits derived from urban forestsuch as purification of air (fresh air) wind break provisionof shade beautification relaxation parks and gardens Fuel-wood animal fodder and edible fruits are among urban forestproducts sold for income generation The higher percentageof respondents who collected fuelwood and animal fodderin Lugbe (periurban centres) compared to Abuja city (urbancentre) could be compared This could be an indication thathigher percentage of periurban residents is more interestedin income generation from urban forests Income generationfrom urban and periurban forest products in Akure Nigeriaranged from $30 to $150 [10 46] which could further attesteconomic viability of urban forests in developing countriesParks and recreation centres employ people as service menand women thus the livelihood of these people dependson the income from these parks and recreation centresRecreational centres differ from one another because of their

relatively small size and type of use with relative amountof income generation for the people and government [10]Recreation centres are suitable places for causal meetingslunch outing associationmeeting family relaxation businessmeetings and holiday relaxation Fuwape andOnyekwelu [2]observed that parks and recreation centres in cities acrossWest Africa serve as small businesses centres communitymeeting religious worship centres and shades for groves insome urban and periurban centres

83 Green Index Mapping Using Normalized Difference Veg-etation Index (NDVI) The low value of Normalized Differ-ence Vegetation Index (NDVI) generated for Abuja provedthat the vegetation coverage is scattered around the citiesIn urban area green spaces play important role in thequality of life and healthy nature of the ecosystem whichwill improve the healthy nature of communities The FederalCapital Territory (FCT) NDVI value indicated the presenceof shrubs and scattered trees around the city Xu et al [47]and Miguel-Anyanz and Biging [48] opined that NDVI val-ues of 01 to minus01 represent degraded land moderate val-ues of 02 to 03 represent shrubs and grass land while06 to 08 represent tropical forest land with vegetationcoverage Gillies and Carlson [49] reported that vegetationcoverage has different impacts on recreation potential andmicroclimate of the environment as well as improving thesocioeconomic values of green spacesNormalizedDifferenceVegetation Index (NDVI) is important parameter for thedeterminant of urban and periurban climate change and theLand Surface Temperature (LST) which relate the temper-ature generation and the cooling system of the vegetationcoverage [50] High level of tree species richness will enhancehealthy vegetation coverage and reduces temperature of theatmosphere through evapotranspiration processes in greenvegetation which would be achieved if the high tree species


richness in Abuja city is both maintained and improvedThere is also need to substantially improve the vegetationcover of Lugbe which is expected to contribute to reduc-ing the usual high seasonal temperature Miller [51] andTurk and Hastaoglu [52] reported that areas where LandSurface Temperature (LST) is low the Normalized DifferenceVegetation Index (NDVI) values measurement are usuallyhigh which a sign of healthy vegetation coverage of the cityThis can as well translate to healthy environment with healthyhumans and other animals it can also increase economicvalues of households

9 Conclusion and Recommendation

The result of this research has provided baseline informa-tion on urban and periurban forests in the Federal CapitalTerritory (FCT) of Nigeria (Abuja) which can be used forthe development of tree species database of the territory Thepotentials of urban andperiurban forests in conserving biodi-versity and providing essential products and services towardsenvironmental management economic empowerment andsocial services to the society were revealed Different goods(edible fruitsseeds vegetables fuelwood herbs animal fod-der etc) and services (parks windbreak pollution reductionbeautification etc) were provided by urban forests in theFCTThe sale of tree products providedmuchneeded incomeespecially for periurban inhabitants

This similarity of tree species richness of Abuja city(urban centre) and some natural forests confirms and under-scores the importance of urban forests in biodiversity conser-vation it is evidence that urban forests can be reservoirs andcontributor to biodiversity conservation The urban centre(Abuja city) had higher tree species richness and diversitythan the periurban areas (Lugbe) The high species richnessand diversity in Abuja city despite its high infrastructuraldevelopment showed that infrastructural development in thecity did not negatively affect its biodiversity conservationpotential The spatial arrangement of trees as well as thechoice and combination of tree species shows that Abuja isa well-landscaped city The maintenance and improvementof the high tree species richness and diversity in Abujacity will enhance healthy vegetation coverage and reducetemperature There is need to substantially improve thevegetation cover of Lugbe in order to reduce its usually highseasonal temperature

Forestry extension services should do more in educatingthe people on the benefits importance and contributionsof urban forest to the environment and the people It isimportant for government at all levels to be involved inplanting trees in urban areas and create measures for thedevelopment of urban forests Therefore during the processof construction expansion and infrastructure developmentattention should be paid to conserving trees rather thancutting them down

Competing Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This research was supported by the International Founda-tion for Science (IFS) Stockholm Sweden through a grant(D5609-1) to Aladesanmi D Agbelade The authors alsoacknowledge International Institute of Tropical Agriculture(IITA) Ibadan Nigeria for scholarship in data processingand Normalized Difference Vegetation Index (NDVI) MapProduction

References

[1] D J Nowak and J F Dwyer ldquoUnderstanding the benefits andcosts of urban forest ecosystemsrdquo in Urban and CommunityForestry in the Northeast J E Kuser Ed pp 25ndash46 SpringerDordrecht The Netherlands 2nd edition 2007

[2] J A Fuwape and J C Onyekwelu ldquoUrban forest developmentin West Africa benefits and challengesrdquo Journal of Biodiversityand Ecological Sciences vol 1 no 1 pp 77ndash94 2011

[3] UN-Habitat State of African Cities Re-Imagining SustainableUrban Transitions UN-Habitat Rapidly Expanding RegionalStstes of Cities Report Series Design and Layout by MichaelJones Software (MJS) Nairobi Kenya 2014

[4] United Nations World Urbanization Prospects The 2014 Revi-sion Department for Economic and Social Affairs UnitedNations New York NY USA 2014

[5] S Angel S C Sheppard and D L Civco The Dynamicsof Global Urban Expansion World Bank Transport UrbanDevelopment Department Washington DC USA 2011

[6] M Rajkumar and N Parthasarathy ldquoChanges in forest compo-sition and structure in three sites of tropical evergreen forestaround Serigaltheri Western Ghatsrdquo Current Science vol 53pp 389ndash393 2008

[7] K C Seto A Reenberg C G Boone et al ldquoUrban landteleconnections and sustainabilityrdquo Proceedings of the NationalAcademy of Sciences vol 109 no 20 pp 7687ndash7692 2012

[8] P O Akunnaya and O Adedapo ldquoTrends in urbanisationimplication for planning and low-income housing delivery inLagos Nigeriardquo Architecture Research vol 4 no 1 pp 15ndash262014

[9] J F Dwyer D J Nowak M H Noble and S M SisinnildquoConnecting people with ecosystems in the 21st century anassessment of our nationrsquos urban forestsrdquo General TechnicalReport PNW-GTR-490 US Department of Agriculture ForestService PNRS Portland Ore USA 2000

[10] J COnyekwelu andD BOlaniyi ldquoSocio-economic importanceofUrban and peri-urban forests inNigeriardquo inProceedings of the6th Annual Conference of SAAT FUTA Adebayo Ed pp 200ndash210 Akure Nigeria November 2012

[11] A D Agbelade J C Onyekwelu and O Apogbona ldquoAssess-ment of Urban tree species population and diversity in IbadanNigeriardquo Environmental and Ecology Research vol 4 no 4 pp185ndash192 2016

[12] C C Konijnendijk RM Ricard A Kenney and T B RandrupldquoDefining urban forestrymdasha comparative perspective of NorthAmerica and EuroperdquoUrban Forestry amp Urban Greening vol 4no 3-4 pp 93ndash103 2006

[13] L M Westphal ldquoUrban greening and social benefits a study ofempowerment outcomesrdquo Journal of Arboriculture vol 29 no3 pp 137ndash147 2003

[14] O Balogun The Geography of Its Development The FederalCapital Territory University Press Ibadan Nigeria 2001


[15] P E Adakayi ldquoClimaterdquo in Geography of Abuja Federal CapitalTerritory P D Dawam Ed FamousAsanlu Publishers AbujaNigeria 2000

[16] F Ujoh I D Kwabe and O O Ifatimehin ldquoUnderstandingurban sprawl in the Federal Capital City Abuja towardssustainable urbanization in Nigeriardquo Journal of Geography andRegional Planning vol 3 no 5 pp 106ndash113 2010

[17] R W J Keay Trees of Nigeria Oxford University Press OxfordUK 1989

[18] H Liu and A R Huete ldquoA feedback based modification of theNDVI tominimize canopy background and atmospheric noiserdquoIEEETransactions onGeoscience andRemote Sensing vol 33 pp457ndash465 1995

[19] M C Imhoff W T Lawrence C D Elvidge et al ldquoUsingnighttime DMSPOLS images of city lights to estimate theimpact of urban land use on soil resources in the United StatesrdquoRemote Sensing of Environment vol 59 pp 105ndash117 1997

[20] B Husch T W Beers and J A Keenshaw Jr Forest Mensura-tion John Wiley amp Sons Hoboken NJ USA 4th edition 2003

[21] MB BrashearsMA Fajvan andTM Schuler ldquoAn assessmentof canopy stratification and tree species diversity followingclearcutting in central Appalachian hardwoodsrdquo Forest Sciencevol 50 no 1 pp 54ndash64 2004

[22] M P Aidar J R Godoy J Bergmann and C A JolyldquoAtlantic Forest succession over calcareous soil Parque EstadualTurıstico do Alto RibeiramdashPETAR SPrdquo Revista Brasileira deBotanica vol 24 no 4 pp 455ndash469 2001

[23] M Kent and P Coker Vegetation Description and Analysis APractical Approach John Wiley amp Sons Chichester UK 1992

[24] Y Guo P Gong and R Amundson ldquoPedodiversity in theUnited States of Americardquo Geoderma vol 117 no 1-2 pp 99ndash115 2003

[25] P C Nath A Arunachalam M L Khan K Arunachalamand A R Barbhuiya ldquoVegetation analysis and tree populationstructure of tropical wet evergreen forests in and aroundNamdapha National Park northeast Indiardquo Biodiversity andConservation vol 14 no 9 pp 2109ndash2135 2005

[26] T Soslashrenson ldquoA method of establishing groups of equal ampli-tude on similarity of species contentrdquo Biologiske Skrifter KDanske Videnskbernes Selskab vol 5 no 4 pp 1ndash34 1948

[27] European Union ldquoForest biodiversity as a challenge andopportunity for climate change adaptation and mitigationrdquoin Informal Meeting of EU Environment Ministers 12 pagesLjubljana Slovenia April 2008

[28] C M Shackleton ldquoUrban forestrymdasha Cinderella science inSouth Africardquo Southern African Forestry Journal vol 208 pp1ndash14

[29] J C Onyekwelu ldquoUrbanization and challenges of urbanforestry Green economy balancing environmental sustainabil-ity and livelihoods in an emerging economyrdquo in Proceedingsof the 36thannual conference of the Forestry Association ofNigeria Uyo Akwa Ibom State Popoola et al Ed pp 402ndash419November 2013

[30] J C Onyekwelu R Mosandl and B Stimm ldquoTree speciesdiversity and soil status of primary and degraded tropicalrainforest ecosystems in South-Western Nigeriardquo Journal ofTropical Forest Science vol 20 no 3 pp 193ndash204 2008

[31] D L Owen ldquoThe glossary of forestry terminologyrdquo in SouthAfrican Forestry Handbook 2000 D L Owen Ed pp 724ndash734SAIF Pretoria South Africa 2000

[32] R G Lowe ldquoVolume increment of natural moist tropical forestin Nigeriardquo Commonwealth Forestry Review vol 76 no 2 pp109ndash113 1997

[33] V A J Adekunle ldquoConservation of tree species diversity intropical rainforest ecosystem of southwest Nigeriardquo Journal ofTropical Forest Science vol 18 pp 91ndash101 2006

[34] IIRS (Indian Institute of Remote Sensing) BiodiversityCharacterization at Landscape Level in Western Ghats IndiaUsing Satelite Remote Sensing and GIS Department of SpaceDehradun Indian Institute of Remote Sensing NationalRemote Sensing Agency Dehradun India 2002

[35] C Konijnenddijk S Sadio T Randrup and J SchipperijnldquoUrban and peri-urban forestry in a development context-strategy and implementationrdquo Journal of Arboriculture vol 30pp 269ndash276 2004

[36] N Parthasarathy ldquoChanges in forest composition and structurein three sites of tropical evergreen forest around SengaltheriWestern Ghatsrdquo Current Science vol 80 no 3 pp 389ndash3932001

[37] K-C Yang J-K Lin C-F Hsieh et al ldquoVegetation patternand woody species composition of a broad-leaved forest at theupstream basin of Nantzuhsienhsi in mid-southern TaiwanrdquoTaiwania vol 53 no 4 pp 325ndash337 2008

[38] E Duran J A Meave D J Lott and G Segura ldquoStructure andtree diversity patterns at landscape level in a Mexican tropicaldeciduous forestrdquo Boletin De Sociedad Botanica De Mexico vol79 pp 43ndash60 2006

[39] A A Alvey ldquoPromoting and preserving biodiversity in theurban forestrdquo Urban Forestry and Urban Greening vol 5 no 4pp 195ndash201 2006

[40] A Balmford J L Moore T Brooks et al ldquoConservationconflicts across Africardquo Science vol 291 pp 2616ndash2619 2001

[41] J Cornelis and M Hermy ldquoBiodiversity relationships in urbanand suburban parks in Flandersrdquo Landscape and Urban Plan-ning vol 69 pp 385ndash401 2004

[42] I Kuhn R Brandl and S Klotz ldquoThe flora of German cities isnaturally species richrdquo Evolutionary Ecology Research vol 6 pp749ndash764 2004

[43] D J Nowak and J T Walton ldquoProjected urban growth (2000ndash2050) and its estimated impact on the US forest resourcerdquoJournal of Forestry vol 103 pp 383ndash389 2005

[44] C Y Jim and H T Liu ldquoSpecies diversity of three major urbanforest types in Guangzhou City Chinardquo Forest Ecology andManagement vol 146 pp 99ndash114 2001

[45] M B Araujo ldquoThe coincidence of people and biodiversity inEuroperdquo Global Ecology and Biogeography vol 12 pp 5ndash122003

[46] J C Onyekwelu ldquoBiodiversity socio-economic and culturalimportance of trees in emerging Nigerian urban centres casestudy of Akure city Nigeriardquo in Proceedings of the 15th WorldForestry Congress Technical Paper 8 pages Durban SouthAfrica September 2015

[47] H Xu X Wang and G Xiao ldquoA Remote Sensing and GisIntegrated Study On Urbanization with Its Impact On ArableLands Fuqing City Fujian Province Chinardquo Land Degradationamp Development vol 11 no 4 pp 301ndash314 2000

[48] J S Miguel-Anyanz and G S Biging ldquoComparison of single-stage and multi-stage classification approaches for cover typemapping with TM and SPOT datardquo Remote Sensing of Environ-ment vol 59 pp 92ndash104 1997


[49] R R Gillies and T N Carlson ldquoThermal remote sensing ofsurface soil water content with partial vegetation cover forincorporation into climate modelsrdquo Journal of Applied Meteo-rology vol 34 pp 745ndash756 1995

[50] R R Gillies T N Carlson J CuiW P Kustas and K S HumesldquoA verification of the triangle method for obtaining surface soilwater content and energy fluxes from remote measurementsof the Normalized Difference Vegetation Index (NDVI) andsurface radiant temperaturerdquo International Journal of RemoteSensing vol 18 pp 3145ndash3166 1997

[51] R W Miller Urban Forestry Planning and Managing UrbanGreen Spaces Prentice-Hall Upper Saddle River NJ USA 2ndedition 1997

[52] T Turk and K Hastaoglu ldquoMobile GIS application in urbanareas and forest boundaries a case studyrdquo in Proceeding of the5th International Symposium on Mobile Mapping TechnologyPadua University Padua Italy May 2007

Submit your manuscripts athttpswwwhindawicom

Forestry ResearchInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Environmental and Public Health

Journal of



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MeteorologyAdvances in

EcologyInternational Journal of


Marine BiologyJournal of


Hindawi Publishing Corporationhttpwwwhindawicom

Applied ampEnvironmentalSoil Science

Volume 2014

Advances in


Environmental Chemistry

Atmospheric SciencesInternational Journal of



Waste ManagementJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal of

Geophysics


Geological ResearchJournal of

EarthquakesJournal of


BiodiversityInternational Journal of


ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OceanographyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


ClimatologyJournal of


sions due to tropical deforestation and expansion of socialinfrastructure [9]

The increasing population of Abuja city Nigeriarsquos FederalCapital Territory (FCT) has led to a wide range of challengeswhich has now put lots of pressure on land forest and forestresources and green spaces and exposed the city to differentenvironmental hazards Environmental hazards such as airpollution wind and water erosion are on the increase asa result of deforestation and population increase withinthe FCT and this is evident in different parts of Nigeriacities [2 10] In our growing urbanized environments themaintenance and development of urban vegetated areas areamong the challenges of sustainable urban planning [2 11]

Research has suggested that urban forest and urban greenareas could be another effectivemeans of biodiversity conser-vation and ecosystems potentials in terms of physiologicalsociological economic and aesthetic benefits [12] Urbanforests could also be used to reduce the challenges posedby urbanization such as food insecurity energy shortagedeteriorating air quality high temperatures health hazardsand increased noise levels [2] Other benefits derived fromurban forests include healthy environment which translatesto healthy citizens beautification of the environment andscenery cooler air temperature reductions in ultraviolet radi-ation and social and ecological benefits [9 11 13] This studyinvestigates tree species richness diversity and vegetationindex for Federal Capital Territory Abuja Nigeria

2 Methodology

21 Location of Study Area The study was conducted inAbuja the Federal Capital Territory (FCT) of Nigeria Thecity lies between latitude and 9∘031015840 and 9∘071015840N and longitude7∘261015840 and 7∘391015840E in the North central region of NigeriaAbuja experiences tropical wet and dry climate The FCTexperiences a warm humid rainy season and a blistering dryseason (harmattan) occasioned by the northeast trade windwith the main features of dust haze intensified coldness anddryness Rainfall in the FCT reflects the territoryrsquos locationon the windward side of the Jos Plateau and the zone ofrising air masses Balogun [14] opined that due to the hillyand mountainous nature of Abuja city orographic activitiesbring heavy and frequent rainfall during the rainy seasonThe rainy season begins in March and ends in Novemberwith peak in September during which abundant rainfall isreceivedMean annual rainfall inAbuja ranges from 1000mmto 1600mm Mean monthly temperature ranges between258∘C and 302∘C [14 15] The soils of the study area arebasically Alluvial and Luvisols which supports growth of treespecies such as Khaya spp Parkia biglobosa Delonix regiaEucalyptus spp Azadirachta indica and Gmelina arborea[16]

Lugbe is one of the popular suburban settlements inAbuja It is in the Abuja Municipal Area Council (AMAC)It is largely residential and densely populated Lugbe is about17 minutesrsquo drive from the Central Business District of Abujaand 13 minutesrsquo drive to the Abuja Airport Though Lugbeis not in the Federal Capital City (FCC) its proximity to thecity centre and also to the Abuja Airport has brought it into

lime light and attracted significant development to the areaThe area is developing very fast and it houses the NationalSpace Development and Research Agency Federal HousingAuthority (FHA) Estate and Voice of Nigeria TransmissionStation

3 Data Collection

The city of Abuja was purposefully selected as the urbansector for this research based on its high infrastructural devel-opment population density and its economic importance inNigeriawhile the closest satellite town (Lugbe)was selected asthe periurban settlement Both semistructured questionnaireand biodiversity assessment were used for data collectionThe questionnaire was used to obtain information on thesocioeconomic and environmental benefits of urban forestTwenty respondents were purposefully selected in each urbanand periurban centre of the FCT which translated to a totalof forty (40) questionnaires for this study Administration ofquestionnaires was done using snowball sampling respon-dents were those who own tree(s) or who have association(s)with tree(s) This was supported by earlier study by [11]which used snowball sampling methods due to the pecu-liarity of urban forest development in Ibadan metropolisThese questionnaires were administered in form of interviewguide such that respondents were requested to complete andreturn them immediately thus resulting in 100 retrievalThe study covers 20 of Abuja Federal Capital Territory(FCT) built-up centres The biodiversity assessment entailscomplete enumeration of tree species in public parksgardenprivate gardenshome gardens avenueroadside trees schoolgrounds public and private institutions and any spacewith conglomerates of trees Within the selected urban andperiurban centre all trees with diameter at breast height(dbh)ge 10 cmwere identified their diameters at breast heightdiameters at the base middle and top and total height weremeasured while their frequencies were taken All tree speciesin each city were assigned to families using Keay [17] as guide

4 Data Processing and Analysis

41 Computation of Normalized Difference Vegetation Index(NDVI) Normalized Difference Vegetation Index (NDVI)is one of the most widely used vegetation indices which isapplicable in satellite analysis and monitoring of vegetationcover [18 19] In this study the NDVI was calculated inArcGIS 103 environment using

NDVI = NIR minus VISNIR + VIS (1)

whereNDVI isNormalizedDifferenceVegetation IndexNIRis near infrared and VIS is visible red reflectance

The value of the pixels varies between minus1 and +1 thehigher the value of NDVI the richer and healthier thevegetation cover of such environment

42 Computation of Growth Parameters and BiodiversityIndices Thecomputations of the following growth parameterand biodiversity indices were undertaken



BA = 1205871198632

4 (2)



119881 = 120587ℎ1198631198872 + 4 (1198631198982) +119863119905224 (3)



RD = ( 119899119894119873) times 100 (4)






IVI = (RD + RD119900)2 (6)


1198671015840 = minus119904

sum119894=1

119875119894 ln (119875119894) (7)



119867max = ln (119878) (8)



119864119867 = 1198671015840

119867max= minussum

119904119894=1 119875119894 ln (119875119894)ln (119878) (9)


SI = ( 2119862119886 + 119887) times 100 (10)



5 Results





























Table 2 Continued







7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

Selected areas


Low minus00765043

N

0 175 35 7 105 14

(Kilometers)

(a)

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

Selected areas

NDVI value

N

High 00416667

Low minus046789

0 175 35 7 105 14

(Kilometers)

(b)









8 Discussion




















Competing Interests


Acknowledgments


References



























































Journal of












Volume 2014

Advances in









Geophysics
















BA = 1205871198632

4 (2)



119881 = 120587ℎ1198631198872 + 4 (1198631198982) +119863119905224 (3)



RD = ( 119899119894119873) times 100 (4)






IVI = (RD + RD119900)2 (6)


1198671015840 = minus119904

sum119894=1

119875119894 ln (119875119894) (7)



119867max = ln (119878) (8)



119864119867 = 1198671015840

119867max= minussum

119904119894=1 119875119894 ln (119875119894)ln (119878) (9)


SI = ( 2119862119886 + 119887) times 100 (10)



5 Results





























Table 2 Continued







7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

Selected areas


Low minus00765043

N

0 175 35 7 105 14

(Kilometers)

(a)

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

Selected areas

NDVI value

N

High 00416667

Low minus046789

0 175 35 7 105 14

(Kilometers)

(b)









8 Discussion




















Competing Interests


Acknowledgments


References



























































Journal of












Volume 2014

Advances in









Geophysics









































Table 2 Continued







7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

Selected areas


Low minus00765043

N

0 175 35 7 105 14

(Kilometers)

(a)

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

Selected areas

NDVI value

N

High 00416667

Low minus046789

0 175 35 7 105 14

(Kilometers)

(b)









8 Discussion




















Competing Interests


Acknowledgments


References



























































Journal of












Volume 2014

Advances in









Geophysics















7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

Selected areas


Low minus00765043

N

0 175 35 7 105 14

(Kilometers)

(a)

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

7∘15

9984000998400998400E 7

∘18

9984000998400998400E 7

∘21

9984000998400998400E 7

∘24

9984000998400998400E 7

∘27

9984000998400998400E 7

∘30

9984000998400998400E 7

∘33

9984000998400998400E 7

∘36

9984000998400998400E

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

9∘12

9984000998400998400N

9∘99984000998400998400N

9∘69984000998400998400N

9∘39984000998400998400N

9∘09984000998400998400N

8∘57

9984000998400998400N

Selected areas

NDVI value

N

High 00416667

Low minus046789

0 175 35 7 105 14

(Kilometers)

(b)









8 Discussion




















Competing Interests


Acknowledgments


References



























































Journal of












Volume 2014

Advances in









Geophysics



















8 Discussion




















Competing Interests


Acknowledgments


References



























































Journal of












Volume 2014

Advances in









Geophysics





























Competing Interests


Acknowledgments


References



























































Journal of












Volume 2014

Advances in









Geophysics


























































Journal of












Volume 2014

Advances in









Geophysics














Research Article Tree Species Richness, Diversity, and ...

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Transcript of Research Article Tree Species Richness, Diversity, and ...