Hindawi
International Journal of Forestry Research
Volume 2017, Article ID 4549756, 12 pages
https://doi.org/10.1155/2017/4549756
Research Article
Tree Species Richness, Diversity, and Vegetation
Index for Federal Capital Territory, Abuja, Nigeria
Aladesanmi D Agbelade,1 Jonathan C. Onyekwelu,2 and Matthew B. Oyun2
1
Department of Forest Resources and Wildlife Management, Faculty of Agricultural Sciences,
Ekiti State University, PMB 5363, Ado Ekiti, Ekiti State, Nigeria
2
Department of Forestry and Wood Technology, School of Agriculture and Agricultural Technology,
Federal University of Technology, PMB 704, Akure, Ondo State, Nigeria
Correspondence should be addressed to Aladesanmi D Agbelade; aladesanmi2008@gmail.com
Received 3 August 2016; Revised 13 November 2016; Accepted 28 November 2016; Published 31 January 2017
Academic Editor: Piermaria Corona
Copyright © 2017 Aladesanmi D Agbelade et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This study was conducted to investigate the tree species richness and diversity of urban and periurban areas of the Federal Capital
Territory (FCT), Abuja, Nigeria, and produce Normalized Difference Vegetation Index (NDVI) for the territory. Data were collected
from urban (Abuja city) and periurban (Lugbe) areas of the FCT using both semistructured questionnaire and inventory of tree
species within green areas. In the study location, all trees with diameter at breast height (dbh) ≥ 10 cm were identified; their dbh was
measured and frequency was taken. The NDVI was calculated in ArcGIS 10.3 environment using standard formula. A cumulative
total 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 (𝐻 ) for the two centres are 3.56 and 2.24 while
Shannon’s maximum diversity index (𝐻max ) is 6.54 (Abuja city) and 5.36 (Lugbe) for the urban (Abuja city) and periurban (Lugbe)
areas of the Federal Capital Territory (FCT). The result of tree species evenness (Shannon’s equitability (𝐸𝐻 ) index) in urban and
periurban centres was 0.54 and 0.42, respectively. The study provided baseline information on urban and periurban forests in the
FCT 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 other
vegetative covers that play important role in human life.
Urban forests serve important roles such as tree species
diversity conservation and protection of fragile ecosystem;
development of parks and event centres for relaxation and
social engagements; provision of vegetable and fruits/seeds
for foods and medicines; and purification of air, wind
break, and beautification of the environment [1]. Research
in developing countries has revealed that trees are planted
around houses for fruits, nuts, leaves, fuelwood, fodder,
vegetables, shade, and windbreaks [2]. In traditional African
settlements, it is usually common to plant trees in village
squares to provide shade for social meetings, ceremonies,
recreation, and religious worships. The growing urban population in Nigeria is redefining urban forestry practices
and has presented new challenges and opportunities for
researchers.
Urbanization in developing countries is on the increase
and this has resulted in social burden in the urban cities due
to their limited capacity to adapt to socioeconomic challenges
of the new environments [3]. Global projections indicate
that future trends in urbanization could triple between
2000 and 2030 [4–7]. According to 2011 revision of World
Urbanization Prospects, the urban areas of the world is
expected to gain 1.4 billion people between 2011 and 2030,
37% of which will come from China (276 million) and India
(218 million). The report predicts that between 2030 and
2050 another 1.3 billion people will be added to the global
urban population. With a total addition of 121 million people,
Nigeria will be the second major contributor next to India
(270 million) [8]. The negative effect of urban expansion
includes threat to ecosystem biodiversity and carbon emis-
2
sions due to tropical deforestation and expansion of social
infrastructure [9].
The increasing population of Abuja city, Nigeria’s Federal
Capital Territory (FCT), has led to a wide range of challenges
which has now put lots of pressure on land, forest and forest
resources, and green spaces and exposed the city to different
environmental hazards. Environmental hazards such as air
pollution, wind, and water erosion are on the increase as
a result of deforestation and population increase within
the FCT and this is evident in different parts of Nigeria
cities [2, 10]. In our growing urbanized environments, the
maintenance and development of urban vegetated areas are
among the challenges of sustainable urban planning [2, 11].
Research has suggested that urban forest and urban green
areas could be another effective means of biodiversity conservation and ecosystems potentials in terms of physiological,
sociological, economic, and aesthetic benefits [12]. Urban
forests could also be used to reduce the challenges posed
by urbanization such as food insecurity, energy shortage,
deteriorating air quality, high temperatures, health hazards,
and increased noise levels [2]. Other benefits derived from
urban forests include healthy environment which translates
to healthy citizens, beautification of the environment and
scenery, cooler air temperature, reductions in ultraviolet radiation, and social and ecological benefits [9, 11, 13]. This study
investigates tree species richness, diversity, and vegetation
index for Federal Capital Territory, Abuja, Nigeria.
2. Methodology
2.1. Location of Study Area. The study was conducted in
Abuja, the Federal Capital Territory (FCT) of Nigeria. The
city lies between latitude and 9∘ 03 and 9∘ 07 N and longitude
7∘ 26 and 7∘ 39 E in the North central region of Nigeria.
Abuja experiences tropical wet and dry climate. The FCT
experiences a warm, humid rainy season and a blistering dry
season (harmattan), occasioned by the northeast trade wind,
with the main features of dust haze, intensified coldness, and
dryness. Rainfall in the FCT reflects the territory’s location
on the windward side of the Jos Plateau and the zone of
rising air masses. Balogun [14] opined that, due to the hilly
and mountainous nature of Abuja city, orographic activities
bring heavy and frequent rainfall during the rainy season.
The rainy season begins in March and ends in November,
with peak in September, during which abundant rainfall is
received. Mean annual rainfall in Abuja ranges from 1000 mm
to 1600 mm. Mean monthly temperature ranges between
25.8∘ C and 30.2∘ C [14, 15]. The soils of the study area are
basically Alluvial and Luvisols, which supports growth of tree
species such as Khaya spp., Parkia biglobosa, Delonix regia,
Eucalyptus spp., Azadirachta indica, and Gmelina arborea
[16].
Lugbe is one of the popular suburban settlements in
Abuja. It is in the Abuja Municipal Area Council (AMAC).
It is largely residential and densely populated. Lugbe is about
17 minutes’ drive from the Central Business District of Abuja
and 13 minutes’ drive to the Abuja Airport. Though Lugbe
is not in the Federal Capital City (FCC), its proximity to the
city centre and also to the Abuja Airport has brought it into
International Journal of Forestry Research
lime light and attracted significant development to the area.
The area is developing very fast and it houses the National
Space Development and Research Agency, Federal Housing
Authority (FHA) Estate, and Voice of Nigeria Transmission
Station.
3. Data Collection
The city of Abuja was purposefully selected as the urban
sector for this research based on its high infrastructural development, population density, and its economic importance in
Nigeria while the closest satellite town (Lugbe) was selected as
the periurban settlement. Both semistructured questionnaire
and biodiversity assessment were used for data collection.
The questionnaire was used to obtain information on the
socioeconomic and environmental benefits of urban forest.
Twenty respondents were purposefully selected in each urban
and periurban centre of the FCT, which translated to a total
of forty (40) questionnaires for this study. Administration of
questionnaires was done using snowball sampling; respondents 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 peculiarity of urban forest development in Ibadan metropolis.
These questionnaires were administered in form of interview
guide, such that respondents were requested to complete and
return them immediately, thus resulting in 100% retrieval.
The study covers 20% of Abuja Federal Capital Territory
(FCT) built-up centres. The biodiversity assessment entails
complete enumeration of tree species in public parks/garden,
private gardens/home gardens, avenue/roadside trees, school
grounds, public and private institutions, and any space
with conglomerates of trees. Within the selected urban and
periurban centre, all trees with diameter at breast height
(dbh) ≥ 10 cm were identified; their diameters at breast height,
diameters at the base, middle, and top, and total height were
measured while their frequencies were taken. All tree species
in each city were assigned to families using Keay [17] as guide.
4. Data Processing and Analysis
4.1. Computation of Normalized Difference Vegetation Index
(NDVI). Normalized Difference Vegetation Index (NDVI)
is one of the most widely used vegetation indices, which is
applicable in satellite analysis and monitoring of vegetation
cover [18, 19]. In this study, the NDVI was calculated in
ArcGIS 10.3 environment using
NDVI =
NIR − VIS
,
NIR + VIS
(1)
where NDVI is Normalized Difference Vegetation Index, NIR
is near infrared, and VIS is visible red reflectance.
The value of the pixels varies between −1 and +1; the
higher the value of NDVI, the richer and healthier the
vegetation cover of such environment.
4.2. Computation of Growth Parameters and Biodiversity
Indices. The computations of the following growth parameter
and biodiversity indices were undertaken.
International Journal of Forestry Research
3
4.2.1. Basal Area. The basal area of all trees in this study area
was calculated using
BA =
𝜋𝐷2
,
4
(2)
where BA is basal area (m ), 𝐷 is diameter at breast height
(cm), and 𝜋 is pie (3.142). The total BA for the city was
obtained by adding all trees BA in the city.
2
4.2.2. Volume. Volume of individual trees was estimated
using tree volume equation developed Newton’s formula as
follows [20]:
𝑉 = 𝜋ℎ
𝐷𝑏2 + 4 (𝐷𝑚2 ) +𝐷𝑡2
24
,
(3)
where 𝑉 is tree volume (m3 ), 𝐷𝑏, 𝐷𝑚, and 𝐷𝑡 are diameters
(m) at the base, middle, and top of each tree, and ℎ is total
tree height (m).
4.2.3. Species Relative Density (RD). Species relative density,
which is an index for assessing species relative distribution
[21], was computed with
RD = (
𝑛𝑖
) × 100,
𝑁
(4)
where RD (%) is species relative density; 𝑛𝑖 is the number
of individuals of species 𝑖; and 𝑁 is the total number of all
individual trees of all species in the entire community.
4.2.4. Species Relative Dominance (RD𝑜 ). Species Relative
Dominance (RD𝑜 (%)), used in assessing relative space
occupancy of a tree, was estimated using [22]
RD𝑜 =
(∑ Ba𝑖 × 100)
,
∑ Ba𝑛
(5)
where Ba𝑖 is basal area of all trees belonging to a particular
species 𝑖 and Ba𝑛 is basal area of all trees in a city.
4.2.5. Importance Value Index (IVI). The Importance Value
Index (IVI) of each species was computed with the relationship in the following equation [21]:
IVI =
(RD + RD𝑜 )
.
2
(6)
4.2.6. Species Diversity Index. Species diversity index (𝐻 )
was computed using the Shannon-Wiener diversity index in
the following equation [23, 24]:
𝑠
𝐻 = −∑𝑃𝑖 ln (𝑃𝑖 ) ,
𝑖=1
(7)
where 𝐻 is Shannon-Wiener diversity index; 𝑠 is the total
number of species in the community; 𝑃𝑖 is the proportion of
S made up of the ith species; and ln is natural logarithm.
4.2.7. Shannon’s Maximum Diversity Index. Shannon’s maximum diversity index was calculated using [24]
𝐻max = ln (𝑆) ,
(8)
where 𝐻max is Shannon’s maximum diversity index and 𝑆 is
the total number of species in the community.
4.2.8. Species Evenness. Species evenness in each city was
determined using Shannon’s equitability (𝐸𝐻), which was
obtained using [23]
𝐸𝐻 =
− ∑𝑠𝑖=1 𝑃𝑖 ln (𝑃𝑖 )
𝐻
.
=
𝐻max
ln (𝑆)
(9)
4.2.9. Sorensen’s Species Similarity Index. Sorensen’s species
similarity index between two cities was calculated using [25,
26]
SI = (
2𝐶
) × 100,
𝑎+𝑏
(10)
where 𝐶 is the number of species in sites 𝑎 and 𝑏 and 𝑎 and 𝑏
= number of species at sites 1 and 2, respectively.
4.3. Data Analyses. After retrieval, the questionnaires were
coded to obtain quantitative values for statistical analysis.
Descriptive analysis was used to summarise the data while
correlation analysis was used to investigate the relationships
between some biodiversity indices and growth variables.
Student’s t-test was used to test for significant difference in the
growth variables of individual trees in urban and periurban
areas for the study. All statistical analyses were undertaken
using Statistical Package for Social Sciences (SPSS 20.0)
software package. Normalized Difference Vegetation Index
of the entire city was calculated and analysed in ArcGIS 10.3
environment to determine the level of greenness of the city
between 2000 and 2015.
5. Results
5.1. Biodiversity Indices and Growth Variables. A cumulative
total of twenty-nine (29) families were encountered within
the FCT, with 27 occurring in Abuja city (i.e., urban centre)
and 12 in Lugbe (i.e., periurban centre) of the FCT (Table 1).
Within the urban and periurban areas, families with high
number of tree species include Fabaceae, Moraceae, Euphorbiaceae, Combretaceae, Arecaceae, and Myrtaceae. A pooled
total of 69 in Abuja city and 20 in Lugbe were identified
within the FCT. Numbers of tree species were higher in the
urban centre (Abuja city) than in the periurban area (Lugbe)
(Table 1). The results of Student’s t-test showed that both
number of family and tree species were significantly higher
in the urban area than the periurban area of the FCT. Based
on the results of tree growth parameters, the trees in the
urban area were larger than those in the periurban area.
Results in Table 1 show that mean dbh (59.3 cm), basal area
(51.03 m2 ), volume (752.8 m3 ), and maximum dbh (212.3 cm)
of tree in Abuja city (urban area) were significantly higher
than the values recorded for the corresponding parameters
4
International Journal of Forestry Research
Table 1: Summary result of biodiversity indices and growth parameters for tree species in urban and periurban areas of FCT.
Benefits derived
Number of individual trees
Number of species
Number of families
Mean Dbh (cm)
Basal area (m2 )
Maximum Dbh (cm)
Volume (m3 )
Diversity index (𝐻 )
Max diversity (𝐻max )
Species evenness (𝐸𝐻 )
Federal Capital Territory (FCT)
Periurban forest
Urban forest
a
213b
695
20b
69a
a
12b
27
16.2b
59.3a
13.70b
51.03a
a
190.7b
212.3
191b
752.8a
2.24b
3.56a
a
5.36b
6.54
a
0.42a
0.54
Values followed by similar letters are not significantly different (𝑝 > 0.05).
in Lugbe (periurban area). Also, the frequency of occurrence
of individual trees in urban area of Abuja was significantly
higher than that of the periurban centre of the city.
The results of Shannon-Wiener diversity index (𝐻 ) for
the two centres are 3.56 and 2.24 while Shannon’s maximum
diversity index (𝐻max ) is 6.54 (Abuja city) and 5.36 (Lugbe)
for the urban (Abuja city) and periurban (Lugbe) areas of
the Federal Capital Territory (FCT). The result of tree species
evenness (Shannon’s equitability (𝐸𝐻) index) in urban and
periurban centres was 0.54 and 0.42, respectively.
The result also revealed that the species relative density
(RD) for individual trees in the urban and periurban centres
of the FCT ranged from 0.14 to 10.41% in Abuja city and
from 0.47 to 33.80% Lugbe (Tables 2 and 3). Tree species
with high relative density (RD) in Lugbe were Gmelina
arborea, Parkia biglobosa, and Mangifera indica, accounting
for 33.80%, 12.21%, and 9.39%, respectively, while in Abuja
city Gmelina arborea (10.40%), Terminalia ivorensis (6.07%),
and Delonix regia (5.35%) had high relative density. Species
Relative Dominance (RD𝑜 ) varied from 0.04 to 6.94% in
Abuja city and from 0.15 to 20.85% in Lugbe. Within the
urban areas (Abuja city), tree species with high Relative
Dominance (RD𝑜 ) were Spathodea campanulata (6.94%),
Nauclea latifolia (5.68%), and Azadirachta indica (5.60%)
while, in the periurban areas (Lugbe) of the FCT, Azadirachta
indica (20.85%), Ricinodendron heudelotii (16.77%), and Nauclea diderrichii (10.59%) dominated. Tree species with high
Importance Value Index were Gmelina arborea (5.82%),
Azadirachta indica (3.96%), and Khaya senegalensis (3.74%)
in Abuja city while Azadirachta indica (14.18%), Parkia biglobosa (10.09%), and Ricinodendron heudelotii (8.62%) were
species with high importance in the floristic composition of
Lugbe (Tables 2 and 3).
5.2. Benefits Derived from Urban Forests. Urban forest benefits are numerous, important, and beneficial to human
livelihood, reduce health related problems, and contribute to
the amelioration of both micro- and macroclimates. Table 4
indicates that people are aware of the various benefits derived
from urban forest. The majority of respondents (70%) in
Lugbe (periurban area) and Abuja (urban area) opined that
they derive fresh air from trees around them. A much
higher percentage (85%) of respondents in the periurban area
derived fuelwood for their cooking purposes from urban
forest when compared to the 10% of respondents in urban
area who indicated that they sourced fuelwood from urban
forests. About 50% and 65% of the respondents in urban
and periurban centres, respectively, derived edible fruits from
trees around them. Between 40 and 50% of the respondents
in urban and periurban centres of the FCT indicated that they
derived vegetables from trees around them, which they used
for their diet. High percentage (60 to 75%) of respondents in
both urban and periurban centres use tree as windbreak to
protect their buildings and other structures. The percentage
of respondents who use trees for shade for the purpose of
social gathering in both urban (Abuja; 60%) and periurban
areas (Lugbe; 75%) is relatively high, which is similar to
the percentage of those who use urban forest facilities for
relaxation/garden/bar/joint purposes (70 to 60%) (Table 4).
About 40% and 50% of the respondents in Abuja city and
Lugbe, respectively, make use of different parts of trees
around them for medicines for curing different diseases
(Table 4).
6. Relationship between Tree
Growth Variables
Generally, there was positive and significant linear relationship between tree growth variables in both urban (Abuja
city) and periurban (Lugbe) areas of the FCT (Tables 5 and
6). The correlation coefficient ranged from 0.16 to 0.96 in
the periurban area (Lugbe) and from 0.26 to 0.97 in the
urban area (Abuja city). The highest correlation coefficient
was obtained between logarithmic transformed basal area
and logarithmic transformed volume for trees in Lugbe
(periurban area), while it was between height and basal
area as well between logarithmic transformed basal area
and logarithmic transformed volume for trees in Abuja city
(urban area). Very weak correlation was observed between
height and basal area (0.16), height and diameter (0.18, 0.26),
and diameter and basal area (0.29) for urban and periurban
centres in the FCT.
7. Results of Thematic Map
Production and Green Area Index
of Federal Capital Territory
The thematic maps of the Federal Capita Territory (FCT)
were produced from its satellite imagery using ArcGIS 10.3,
which led to the generation of Normalized Difference Vegetation Index of the city for the years 2000 and 2015 (Figures
1(a) and 1(b)). Apart from the boundary of each FCT, the
locations visited for data collected and NDVI were shown in
the maps. The boundary was digitized to determine the size
of the FCT, which was georeferenced with the attribute data
collected from the field. The maps produced in this research
reflected the level of flexibility of GIS in creating, calculating,
International Journal of Forestry Research
5
Table 2: Biodiversity indices and growth parameters of individual trees in the urban areas (Abuja city) of the Federal Capital Territory,
Nigeria.
S/N
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Tree species
Adansonia digitata
Albizia falcata
Albizia ferruginea
Alstonia boonei
Anacardium occidentale
Anogeissus leiocarpa
Azadirachta indica
Bambusa vulgaris
Bauhinia monandra
Bauhinia polyantha
Blighia sapida
Bosqueia angolensis
Caesalpinia pulcherrima
Calliandra calothyrsus
Callitris intratropica
Cassia pleurocarpa
Casuarina equisetifolia
Ceiba pentandra
Citrus aurantifolia
Cleistopholis patens
Cocos nucifera
Cola gigantean
Corymbia citriodora
Dacryodes edulis
Daniellia oliveri
Delonix regia
Drypetis spp.
Elaeis guineensis
Eucalyptus camaldulensis
Eucalyptus citriodora
Eucalyptus forrestiana
Euphorbia dendroides
Ficus goliath
Gmelina arborea
Hildegardia baterii
Hura crepitans
Jatropha curcas
Khaya senegalensis
Lophira alata
Lophira procera
Mangifera indica
Milicia excelsa
Milicia regia
Millettia thonningii
Morinda lucida
Moringa oleifera
Nauclea diderrichii
Nauclea latifolia
Parkia biglobosa
Pueraria phaseoloides
Family
Bombacaceae
Fabaceae
Fabaceae
Apocynaceae
Anacardiaceae
Combretaceae
Meliaceae
Poaceae
Fabaceae
Leguminosae
Sapindaceae
Moraceae
Fabaceae
Leguminosae
Cupressaceae
Caesalpiniaceae
Casuarinaceae
Bombacaceae
Rutaceae
Annonaceae
Arecaceae
Malvaceae
Myrtaceae
Burseraceae
Leguminosae
Fabaceae
Nymphalidae
Arecaceae
Myrtaceae
Myrtaceae
Myrtaceae
Euphorbiaceae
Moraceae
Verbenaceae
Malvaceae
Euphorbiaceae
Euphorbiaceae
Meliaceae
Ochnaceae
Ochnaceae
Anacardiaceae
Moraceae
Moraceae
Fabaceae
Rubiaceae
Moringaceae
Rubiaceae
Rubiaceae
Fabaceae
Leguminosae
FQ
3
1
1
1
1
2
16
3
5
1
1
24
3
7
1
7
11
6
9
5
11
1
1
1
20
37
4
1
1
32
10
1
14
72
1
8
1
32
1
3
20
2
1
5
1
2
2
2
26
1
MHt
4.2
19.8
17.0
14.6
18.8
17.1
19.1
16.6
12.7
18.5
13.4
18.8
11.7
8.6
16.8
8.4
10.8
9.5
14.2
15.6
8.4
15.8
13.4
12.6
12.8
14.2
15.0
14.2
11.0
17.6
11.0
8.0
15.5
14.0
15.7
11.6
4.0
17.6
15.2
12.3
11.1
19.6
14.4
13.5
14.8
17.0
15.5
14.3
16.3
13.5
MDbh
51.0
16.0
138.0
86.4
32.0
84.1
11.9
12.8
11.7
105.0
65.0
3.2
6.0
8.3
112.0
4.6
6.6
21.6
7.9
17.4
5.3
109.0
36.0
74.8
7.2
1.2
23.1
47.8
42.0
4.3
4.2
52.0
5.0
1.2
89.6
10.8
16.0
4.3
115.0
15.4
2.1
57.5
90.1
14.5
68.8
16.5
68.0
96.1
4.5
132.0
B.A
1.84
0.02
1.50
0.59
0.08
2.22
2.86
0.12
0.27
0.87
0.33
0.46
0.03
0.26
0.99
0.08
0.41
1.31
0.39
0.59
0.26
0.93
0.10
0.44
1.62
0.17
0.67
0.18
0.14
1.46
0.14
0.21
0.38
0.63
0.63
0.58
0.02
1.46
1.04
0.17
0.13
1.04
0.64
0.41
0.37
0.09
1.45
2.90
1.09
1.37
Vol.
7.72
0.40
25.43
8.56
1.51
37.96
54.56
1.93
3.44
16.02
4.45
8.66
0.30
2.26
16.55
0.69
4.41
12.48
5.61
9.27
2.22
14.75
1.36
5.54
20.70
2.38
10.06
2.55
1.52
25.65
1.50
1.70
5.93
8.83
9.90
6.74
0.08
25.65
15.79
2.07
1.48
20.36
9.18
5.59
5.50
1.45
22.49
41.45
17.80
18.48
RD
0.43
0.14
0.14
0.14
0.14
0.29
2.31
0.43
0.72
0.14
0.14
3.47
0.43
1.01
0.14
1.01
1.59
0.87
1.30
0.72
1.59
0.14
0.14
0.14
2.89
5.35
0.58
0.14
0.14
4.62
1.45
0.14
2.02
10.40
0.14
1.16
0.14
4.62
0.14
0.43
2.89
0.29
0.14
0.72
0.14
0.29
0.29
0.29
3.76
0.14
RD𝑂
3.60
0.04
2.93
1.15
0.16
4.35
5.60
0.23
0.53
1.70
0.65
0.90
0.05
0.52
1.93
0.16
0.80
2.57
0.77
1.17
0.52
1.83
0.20
0.86
3.17
0.33
1.31
0.35
0.27
2.86
0.27
0.42
0.75
1.24
1.24
1.14
0.04
2.86
2.04
0.33
0.26
2.04
1.25
0.81
0.73
0.17
2.84
5.68
2.14
2.68
IVI
2.02
0.09
1.54
0.65
0.15
2.32
3.96
0.33
0.63
0.92
0.40
2.19
0.24
0.76
1.04
0.59
1.19
1.72
1.04
0.94
1.05
0.99
0.17
0.50
3.03
2.84
0.95
0.25
0.21
3.74
0.86
0.28
1.39
5.82
0.69
1.15
0.09
3.74
1.09
0.38
1.58
1.16
0.70
0.77
0.44
0.23
1.57
2.99
2.95
1.41
6
International Journal of Forestry Research
Table 2: Continued.
S/N
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
Tree species
Pinus caribaea
Pinus caribaea
Plumeria alba
Polyalthia longifolia
Psidium guajava
Ravenala madagascariensis
Ricinodendron heudelotii
Roystonea dunlapiana
Roystonea regia
Senna siamea
Spathodea campanulata
Tectona grandis
Terminalia catappa
Terminalia ivorensis
Terminalia macroptera
Terminalia superba
Treculia africana
Vachellia nilotica
Vitex doniana
Family
Pinaceae
Pinaceae
Apocynaceae
Annonaceae
Myrtaceae
Strelitziaceae
Euphorbiaceae
Arecaceae
Arecaceae
Fabaceae
Bignoniaceae
Lamiaceae
Combretaceae
Combretaceae
Combretaceae
Combretaceae
Moraceae
Fabaceae
Verbenaceae
FQ
7
6
19
31
3
1
1
24
21
6
1
11
37
42
31
9
1
17
2
692
MHt
11.9
7.1
12.1
13.2
19.4
15.4
6.8
16.6
17.8
21.2
22.2
16.0
7.9
9.1
11.6
12.7
6.0
9.2
16.4
MDbh
8.0
14.7
3.7
2.5
14.2
36.0
171.0
5.6
3.8
14.8
212.3
10.7
0.7
0.7
3.5
13.6
85.8
3.6
42.5
B.A
0.25
0.61
0.39
0.48
0.14
0.10
2.30
1.40
0.49
0.62
3.54
1.09
0.05
0.08
0.92
1.17
0.58
0.30
0.57
51.02
Vol.
2.95
4.36
4.78
6.32
2.77
1.57
15.62
23.31
8.79
13.13
78.60
17.50
0.37
0.70
10.71
14.85
3.47
2.74
9.31
752.75
RD
1.01
0.87
2.75
4.48
0.43
0.14
0.14
3.47
3.03
0.87
0.14
1.59
5.35
6.07
4.48
1.30
0.14
2.46
0.29
RD𝑂
0.49
1.20
0.77
0.94
0.28
0.20
4.50
2.75
0.97
1.21
6.94
2.14
0.09
0.15
1.81
2.29
1.13
0.58
1.11
IVI
0.75
1.04
1.76
2.71
0.36
0.17
2.32
3.11
2.00
1.04
3.54
1.87
2.72
3.11
3.14
1.80
0.64
1.52
0.70
FQ: number of tree stems in the city, B.A.: 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 Territory,
Nigeria.
S/N
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Tree species
Albizia falcate
Azadirachta indica
Cleistopholis patens
Cocos nucifera
Delonix regia
Elaeis guineensis
Euphorbia dendroides
Ficus goliath
Gmelina arborea
Hildegardia baterii
Jatropha curcas
Mangifera indica
Nauclea diderrichii
Parkia biglobosa
Ravenala madagascariensis
Ricinodendron heudelotii
Senna siamea
Terminalia superba
Treculia Africana
Vachellia nilotica
Family
Fabaceae
Meliaceae
Annonaceae
Arecaceae
Fabaceae
Arecaceae
Euphorbiaceae
Moraceae
Verbenaceae
Malvaceae
Euphorbiaceae
Anacardiaceae
Rubiaceae
Fabaceae
Strelitziaceae
Euphorbiaceae
Fabaceae
Combretaceae
Moraceae
Fabaceae
FQ
1
16
5
11
17
1
1
4
72
1
1
20
2
26
1
1
6
9
1
17
213
MHt
19.8
19.1
15.6
8.4
14.2
14.2
8.0
15.5
14.0
15.7
4.0
11.1
15.5
16.3
15.4
6.8
21.2
12.7
6.0
9.2
MDbh
16.0
11.9
17.4
5.3
2.7
47.8
52.0
17.5
1.2
89.6
16.0
2.1
68.0
4.5
36.0
171.0
14.8
13.6
85.8
3.6
FQ: number of tree stems in the city, B.A.: basal area of trees in the city, Vol.: volume of trees in the city.
B.A
0.02
2.86
0.59
0.26
0.17
0.18
0.21
0.38
0.63
0.63
0.02
0.13
1.45
1.09
0.10
2.30
0.62
1.17
0.58
0.30
13.7
Vol.
0.40
54.56
9.27
2.22
2.38
2.55
1.70
5.93
8.83
9.90
0.08
1.48
22.49
17.80
1.57
15.62
13.13
14.85
3.47
2.74
191.0
RD
0.47
7.51
2.35
5.16
7.98
0.47
0.47
1.88
33.80
0.47
0.47
9.39
0.94
12.21
0.47
0.47
2.82
4.23
0.47
7.98
RD𝑂
0.15
20.85
4.34
1.93
1.22
1.31
1.55
2.79
4.60
4.60
0.15
0.97
10.59
7.97
0.74
16.77
4.52
8.53
4.22
2.18
IVI
0.31
14.18
3.34
3.55
4.60
0.89
1.01
2.34
19.20
2.54
0.31
5.18
5.76
10.09
0.61
8.62
3.67
6.38
2.35
5.08
International Journal of Forestry Research
7∘ 15 0 E
7∘ 18 0 E
7∘ 21 0 E
7
7∘ 24 0 E
7∘ 27 0 E
7∘ 30 0 E
7∘ 33 0 E
7∘ 36 0 E
9∘ 12 0 N
9∘ 12 0 N
9∘ 9 0 N
9∘ 9 0 N
9∘ 6 0 N
9∘ 6 0 N
9∘ 3 0 N
9∘ 3 0 N
9∘ 0 0 N
9∘ 0 0 N
NDVI value
High: 0.326541
N
8∘ 57 0 N
8∘ 57 0 N
7∘ 15 0 E
7∘ 18 0 E
7∘ 21 0 E
7∘ 24 0 E
7∘ 27 0 E
7∘ 30 0 E
7∘ 33 0 E
Low: −0.0765043
7∘ 36 0 E
Selected areas
0 1.75 3.5
7
10.5
(Kilometers)
14
(a)
∘
7 15 0 E
∘
∘
7 18 0 E
∘
7 21 0 E
∘
7 24 0 E
∘
7 27 0 E
7∘ 30 0 E
7∘ 33 0 E
7∘ 36 0 E
∘
9 12 0 N
9 12 0 N
9∘ 9 0 N
9∘ 9 0 N
9∘ 6 0 N
9∘ 6 0 N
9∘ 3 0 N
9∘ 3 0 N
9∘ 0 0 N
9∘ 0 0 N
NDVI value
High: 0.0416667
N
8∘ 57 0 N
8∘ 57 0 N
Low: −0.46789
7∘ 15 0 E
7∘ 18 0 E
7∘ 21 0 E
7∘ 24 0 E
7∘ 27 0 E
7∘ 30 0 E
7∘ 33 0 E
7∘ 36 0 E
Selected areas
0 1.75 3.5
7
10.5
(Kilometers)
14
(b)
Figure 1: (a) Normalized Difference Vegetation Index (NDVI) map for Abuja for the year 2000 and sampling locations. (b) Normalized
Difference Vegetation Index (NDVI) map for Abuja for the year 2015 and sampling locations.
and manipulating different research data for production
of different maps. Normalized Difference Vegetation Index
(NDVI) values of the city were calculated in ArcGIS 10.3
environment to determine the level of greenness of the city.
The NDVI value (0.327) for 2000 was relatively low but
moderate. There was drastic reduction in the NDVI value
(0.042) for 2015 which may be an indication of reduction
and scattering in the vegetative cover of the FCT as a result
8
International Journal of Forestry Research
Table 4: Benefits derived by respondents (%) from urban and
periurban forests in the Federal Capital Territory, Nigeria.
Benefits derived
Medicine (herbs)
Relaxation/garden
Animal fodder
Fuel wood (cooking)
Shade (meetings)
Vegetable (soup)
Fresh air
Beautification
Edible fruits (food)
Windbreak
Abuja (FCT)
Urban area (%)∗
Periurban area (%)∗
40
70
15
10
65
50
70
90
50
60
50
60
50
85
70
40
70
50
65
75
∗
Respondents were allowed to choose more than one option (i.e., multiple
responses).
of infrastructural development and population increase. The
low value of NDVI in year 2015 has greater effects on the
Land Surface Temperature (LST) and climate change of the
city. The lower the NDVI value, the higher the LST, which
tend to expose the city to more higher temperature and the
climate change on the populace. Increase in NDVI value and
reduction in LST value will create conducive environment for
increase in tree diversity and green space coverage.
8. Discussion
8.1. Biodiversity Indices and Tree Growth Yield Variables.
Forest ecosystems are pivotal to the functioning and conserving of biosphere, as they are the origin of many plants
and animals [27]. The urban forests include trees planted
along streets, compounds, school gardens, parks, riverbanks,
city cemeteries, city vacant lots, adjacent wood land, and
anywhere else where trees grow in urban areas [28, 29].
Urban forests are among the in situ conservation methods
that are essential in protecting and conserving tree species for
the greatest benefits of the society. The results of this study
confirmed that urban forest is a repository of many indigenous tropical hardwood and exotic tree species in different
families, judging by the tree species richness of Abuja city,
which is similar to or higher than what has been reported
in some natural forest ecosystems in Nigeria [30–33]. For
example, [30, 31] reported 31 and 51 trees species in tropical
rainforest ecosystems of southwestern Nigeria. A total of 56,
55, and 54 tree species were found in Sapoba, Shasha, and
Ala forest reserves in Nigeria, respectively [32, 33]. Thus, the
large numbers of tree species that are found in tropical forests
[30, 31] could also be said to be characteristics of urban
forest landscapes. This similarity of tree species richness of
urban centres and natural forest ecosystems underscores the
importance of urban forests in biodiversity conservation and
thus is evidence that urban forests can be both reservoirs and
contributor to global biodiversity conservation.
Biodiversity indices of urban and periurban forests are
generated in order to appreciate the level of diversity and
abundance of species in built-up environment. IIRS [34]
noted that biodiversity indices are generated to bring the
diversity and abundance of species in different habitats to
similar scale for comparison and the higher the value, the
greater the species richness.
Konijnenddijk et al. [35] had noted that the levels of
biodiversity in urban and periurban areas are often surprisingly high even when compared with forest trees diversity.
The Shannon-Wiener diversity and Evenness indices of this
study are higher than the values of Parthasarathy [36] and
Yang et al. [37]. In another study, Duran et al. [38] obtained
Shannon-Wiener diversity index range of between 2.69 and
3.33 which is within the range of the values reported for
urban and periurban areas of FCT in this study. The ShannonWiener diversity index of Abuja city (i.e., urban area) in the
study is within the range of the values reported for some
natural tropical forest ecosystems [30, 31, 33] as well as the
values obtained by Agbelade et al. [11] for urban forests
in Ibadan, southwestern Nigeria. However, the ShannonWiener diversity index of Lugbe (i.e., periurban area) is lower
than the values reported by the studies mentioned above. The
implication of this is that urban centres have higher species
diversity than periurban areas, which is further confirmed
by the higher species richness in Abuja city (urban area)
compared to that of Lugbe (periurban area).
Though Alvey [39] reported that, traditionally, urban forest areas have been regarded as locations of low biodiversity
that are dominated by nonnative species; evidence from this
study as well as those from published information is mounting that urban and suburban areas can contain relatively high
levels of biodiversity [40–42]. Contrary to the conclusion of
Alvey [39], there are indications from the results of this study
that urban and periurban forests have good store of both
native and nonnative species. However, a higher percentage
of the very common species are exotic species. Our results
showed that Azadirachta indica, Eucalyptus species, Acacia
species, and Gmelina arborea are the four most common
species in Abuja, which is in agreement with the earlier study
of Fuwape and Onyekwelu [2]. Three of these four most
common species are exotic species. The tree planting and
landscaping mechanism in Abuja may be responsible for the
high level of tree species diversity encountered in it. The
infrastructural development in Abuja city had low impact on
the level of tree species diversity, which could be attributed to
the careful planning, managing, and planting of trees. Thus
it could be concluded that infrastructural development in
Abuja city did not negatively affect the extent of biodiversity
in it. This could imply that landscaping of the city was
considered alongside with the infrastructural development.
The spatial arrangement of trees as well as the choice and
combination of tree species clearly distinguishes Abuja as
a well-landscaped city. Nowak and Walton [43] noted that
expanding urbanization increases the importance of urban
forests in terms of their extent and the critical ecosystem
services they provide to sustain human health and environmental quality in and around urban areas. In Guangzhou
city, China, Jim and Liu [44] found over 250 plant species
International Journal of Forestry Research
9
Table 5: Correlation coefficients for tree growth variables in periurban area (Lugbe).
Height
Diameter
Basal area (BA)
Volume (Vol.)
Ln BA
Ln Vol.
Height
1.00
.18
.16
.41
.17
.44
Diameter
Basal area (BA)
Volume (Vol.)
Ln BA
Ln Vol.
1.00
.96
.86
.93
.88
1.00
.90
.81
.76
1.00
.71
.74
1.00
.96
1.00
Table 6: Correlation coefficients for tree growth variables in urban area (FCT, Abuja).
Height
Diameter
Basal area (BA)
Volume (Vol.)
Ln BA
Ln Vol.
Height
1.00
.26
.97
.87
.94
.91
Diameter
Basal area (BA)
Volume (Vol.)
Ln BA
Ln Vol.
1.00
.26
.47
.25
.49
1.00
.93
.83
.80
1.00
.73
.76
1.00
.96
1.00
after surveying over 115,000 plants in the parks on university
grounds and along streets. This affirmed that there are
relatively high numbers of stems found in urban centre,
which could be higher than the number in conservation
centres. Araújo [45] also asserted that human actions directly
or indirectly increase the total number of species through
introduced species and increase in landscape heterogeneity.
8.2. Benefits Derived from Urban and Periurban Forests. Tree
species encountered in urban and periurban centres of the
Federal Capital Territory, Abuja, are used for food (e.g., edible
fruits/seeds, vegetables), nutrition supplement, medicinal
substances, fuelwood, and animal fodder. Onyekwelu and
Olaniyi [10] had observed that urban forestry practices
improve food security of poor urban inhabitants through
collection of wild edible plants as vegetable, planting of lowcare fruit bearing trees, including a gardening component,
in multifunctional parks, or creating edible public parks.
There are environmental benefits derived from urban forest
such as purification of air (fresh air) wind break, provision
of shade, beautification, relaxation parks, and gardens. Fuelwood, animal fodder, and edible fruits are among urban forest
products sold for income generation. The higher percentage
of respondents who collected fuelwood and animal fodder
in Lugbe (periurban centres) compared to Abuja city (urban
centre) could be compared. This could be an indication that
higher percentage of periurban residents is more interested
in income generation from urban forests. Income generation
from urban and periurban forest products in Akure, Nigeria,
ranged from $30 to $150 [10, 46], which could further attest
economic viability of urban forests in developing countries.
Parks and recreation centres employ people as service men
and women; thus the livelihood of these people depends
on the income from these parks and recreation centres.
Recreational centres differ from one another because of their
relatively small size and type of use with relative amount
of income generation for the people and government [10].
Recreation centres are suitable places for causal meetings,
lunch outing, association meeting, family relaxation, business
meetings, and holiday relaxation. Fuwape and Onyekwelu [2]
observed that parks and recreation centres in cities across
West Africa serve as small businesses centres, community
meeting, religious worship centres, and shades for groves in
some urban and periurban centres.
8.3. Green Index Mapping Using Normalized Difference Vegetation Index (NDVI). The low value of Normalized Difference Vegetation Index (NDVI) generated for Abuja proved
that the vegetation coverage is scattered around the cities.
In urban area, green spaces play important role in the
quality of life and healthy nature of the ecosystem, which
will improve the healthy nature of communities. The Federal
Capital Territory (FCT) NDVI value indicated the presence
of shrubs and scattered trees around the city. Xu et al. [47]
and Miguel-Anyanz and Biging [48] opined that NDVI values of 0.1 to −0.1 represent degraded land; moderate values of 0.2 to 0.3 represent shrubs and grass land while
0.6 to 0.8 represent tropical forest land with vegetation
coverage. Gillies and Carlson [49] reported that vegetation
coverage has different impacts on recreation potential and
microclimate of the environment, as well as improving the
socioeconomic values of green spaces. Normalized Difference
Vegetation Index (NDVI) is important parameter for the
determinant of urban and periurban climate change and the
Land Surface Temperature (LST), which relate the temperature generation and the cooling system of the vegetation
coverage [50]. High level of tree species richness will enhance
healthy vegetation coverage and reduces temperature of the
atmosphere through evapotranspiration processes in green
vegetation, which would be achieved if the high tree species
10
richness in Abuja city is both maintained and improved.
There is also need to substantially improve the vegetation
cover of Lugbe, which is expected to contribute to reducing the usual high seasonal temperature. Miller [51] and
Türk and Hastaoğlu [52] reported that areas where Land
Surface Temperature (LST) is low, the Normalized Difference
Vegetation Index (NDVI) values measurement are usually
high which a sign of healthy vegetation coverage of the city.
This can as well translate to healthy environment with healthy
humans and other animals; it can also increase economic
values of households.
9. Conclusion and Recommendation
The result of this research has provided baseline information on urban and periurban forests in the Federal Capital
Territory (FCT) of Nigeria (Abuja), which can be used for
the development of tree species database of the territory. The
potentials of urban and periurban forests in conserving biodiversity and providing essential products and services towards
environmental management, economic empowerment, and
social services to the society were revealed. Different goods
(edible fruits/seeds, vegetables, fuelwood, herbs, animal fodder, etc.) and services (parks, windbreak, pollution reduction,
beautification, etc.) were provided by urban forests in the
FCT. The sale of tree products provided much needed income,
especially for periurban inhabitants.
This similarity of tree species richness of Abuja city
(urban centre) and some natural forests confirms and underscores the importance of urban forests in biodiversity conservation; it is evidence that urban forests can be reservoirs and
contributor to biodiversity conservation. The urban centre
(Abuja city) had higher tree species richness and diversity
than the periurban areas (Lugbe). The high species richness
and diversity in Abuja city, despite its high infrastructural
development, showed that infrastructural development in the
city did not negatively affect its biodiversity conservation
potential. The spatial arrangement of trees as well as the
choice and combination of tree species shows that Abuja is
a well-landscaped city. The maintenance and improvement
of the high tree species richness and diversity in Abuja
city will enhance healthy vegetation coverage and reduce
temperature. There is need to substantially improve the
vegetation cover of Lugbe in order to reduce its usually high
seasonal temperature.
Forestry extension services should do more in educating
the people on the benefits, importance, and contributions
of urban forest to the environment and the people. It is
important for government at all levels to be involved in
planting trees in urban areas and create measures for the
development of urban forests. Therefore, during the process
of construction, expansion and infrastructure development
attention should be paid to conserving trees rather than
cutting them down.
Competing Interests
The authors declare that there is no conflict of interests
regarding the publication of this paper.
International Journal of Forestry Research
Acknowledgments
This research was supported by the International Foundation for Science (IFS), Stockholm, Sweden, through a grant
(D/5609-1) to Aladesanmi D. Agbelade. The authors also
acknowledge International Institute of Tropical Agriculture
(IITA), Ibadan, Nigeria, for scholarship in data processing
and Normalized Difference Vegetation Index (NDVI) Map
Production.
References
[1] D. J. Nowak and J. F. Dwyer, “Understanding the benefits and
costs of urban forest ecosystems,” in Urban and Community
Forestry in the Northeast, J. E. Kuser, Ed., pp. 25–46, Springer,
Dordrecht, The Netherlands, 2nd edition, 2007.
[2] J. A. Fuwape and J. C. Onyekwelu, “Urban forest development
in West Africa: benefits and challenges,” Journal of Biodiversity
and Ecological Sciences, vol. 1, no. 1, pp. 77–94, 2011.
[3] UN-Habitat, State of African Cities; Re-Imagining Sustainable
Urban Transitions, UN-Habitat Rapidly Expanding Regional
Ststes of Cities Report Series, Design and Layout by Michael
Jones Software (MJS), Nairobi, Kenya, 2014.
[4] United Nations, World Urbanization Prospects: The 2014 Revision, Department for Economic and Social Affairs, United
Nations, New York, NY, USA, 2014.
[5] S. Angel, S. C. Sheppard, and D. L. Civco, The Dynamics
of Global Urban Expansion, World Bank, Transport, Urban
Development Department, Washington, DC, USA, 2011.
[6] M. Rajkumar and N. Parthasarathy, “Changes in forest composition and structure in three sites of tropical evergreen forest
around Serigaltheri, Western Ghats,” Current Science, vol. 53,
pp. 389–393, 2008.
[7] K. C. Seto, A. Reenberg, C. G. Boone et al., “Urban land
teleconnections and sustainability,” Proceedings of the National
Academy of Sciences, vol. 109, no. 20, pp. 7687–7692, 2012.
[8] P. O. Akunnaya and O. Adedapo, “Trends in urbanisation:
implication for planning and low-income housing delivery in
Lagos, Nigeria,” Architecture Research, vol. 4, no. 1, pp. 15–26,
2014.
[9] J. F. Dwyer, D. J. Nowak, M. H. Noble, and S. M. Sisinni,
“Connecting people with ecosystems in the 21st century: an
assessment of our nation’s urban forests,” General Technical
Report PNW-GTR-490, U.S. Department of Agriculture, Forest
Service, PNRS, Portland, Ore, USA, 2000.
[10] J. C. Onyekwelu and D. B. Olaniyi, “Socio-economic importance
of Urban and peri-urban forests in Nigeria,” in Proceedings of the
6th Annual Conference of SAAT, FUTA, Adebayo, Ed., pp. 200–
210, Akure, Nigeria, November 2012.
[11] A. D. Agbelade, J. C. Onyekwelu, and O. Apogbona, “Assessment of Urban tree species population and diversity in Ibadan,
Nigeria,” Environmental and Ecology Research, vol. 4, no. 4, pp.
185–192, 2016.
[12] C. C. Konijnendijk, R. M. Ricard, A. Kenney, and T. B. Randrup,
“Defining urban forestry—a comparative perspective of North
America and Europe,” Urban Forestry & Urban Greening, vol. 4,
no. 3-4, pp. 93–103, 2006.
[13] L. M. Westphal, “Urban greening and social benefits: a study of
empowerment outcomes,” Journal of Arboriculture, vol. 29, no.
3, pp. 137–147, 2003.
[14] O. Balogun, The Geography of Its Development, The Federal
Capital Territory University Press, Ibadan, Nigeria, 2001.
International Journal of Forestry Research
[15] P. E. Adakayi, “Climate,” in Geography of Abuja, Federal Capital
Territory, P. D. Dawam, Ed., Famous/Asanlu Publishers, Abuja,
Nigeria, 2000.
[16] F. Ujoh, I. D. Kwabe, and O. O. Ifatimehin, “Understanding
urban sprawl in the Federal Capital City, Abuja: towards
sustainable urbanization in Nigeria,” Journal of Geography and
Regional Planning, vol. 3, no. 5, pp. 106–113, 2010.
[17] R. W. J. Keay, Trees of Nigeria, Oxford University Press, Oxford,
UK, 1989.
[18] H. Liu and A. R. Huete, “A feedback based modification of the
NDVI to minimize canopy background and atmospheric noise,”
IEEE Transactions on Geoscience and Remote Sensing, vol. 33, pp.
457–465, 1995.
[19] M. C. Imhoff, W. T. Lawrence, C. D. Elvidge et al., “Using
nighttime DMSP/OLS images of city lights to estimate the
impact of urban land use on soil resources in the United States,”
Remote Sensing of Environment, vol. 59, pp. 105–117, 1997.
[20] B. Husch, T. W. Beers, and J. A. Keenshaw Jr., Forest Mensuration, John Wiley & Sons, Hoboken, NJ, USA, 4th edition, 2003.
[21] M. B. Brashears, M. A. Fajvan, and T. M. Schuler, “An assessment
of canopy stratification and tree species diversity following
clearcutting in central Appalachian hardwoods,” Forest Science,
vol. 50, no. 1, pp. 54–64, 2004.
[22] M. P. Aidar, J. R. Godoy, J. Bergmann, and C. A. Joly,
“Atlantic Forest succession over calcareous soil, Parque Estadual
Turı́stico do Alto Ribeira—PETAR, SP,” Revista Brasileira de
Botânica, vol. 24, no. 4, pp. 455–469, 2001.
[23] M. Kent and P. Coker, Vegetation Description and Analysis: A
Practical Approach, John Wiley & Sons, Chichester, UK, 1992.
[24] Y. Guo, P. Gong, and R. Amundson, “Pedodiversity in the
United States of America,” Geoderma, vol. 117, no. 1-2, pp. 99–
115, 2003.
[25] P. C. Nath, A. Arunachalam, M. L. Khan, K. Arunachalam,
and A. R. Barbhuiya, “Vegetation analysis and tree population
structure of tropical wet evergreen forests in and around
Namdapha National Park, northeast India,” Biodiversity and
Conservation, vol. 14, no. 9, pp. 2109–2135, 2005.
[26] T. Sørenson, “A method of establishing groups of equal amplitude on similarity of species content,” Biologiske Skrifter K.
Danske Videnskbernes Selskab, vol. 5, no. 4, pp. 1–34, 1948.
[27] European Union, “Forest biodiversity as a challenge and
opportunity for climate change adaptation and mitigation,”
in Informal Meeting of EU Environment Ministers, 12 pages,
Ljubljana, Slovenia, April 2008.
[28] C. M. Shackleton, “Urban forestry—a Cinderella science in
South Africa?” Southern African Forestry Journal, vol. 208, pp.
1–14.
[29] J. C. Onyekwelu, “Urbanization and challenges of urban
forestry. Green economy: balancing environmental sustainability and livelihoods in an emerging economy,” in Proceedings
of the 36thannual conference of the Forestry Association of
Nigeria, Uyo, Akwa Ibom State, Popoola et al., Ed., pp. 402–419,
November 2013.
[30] J. C. Onyekwelu, R. Mosandl, and B. Stimm, “Tree species
diversity and soil status of primary and degraded tropical
rainforest ecosystems in South-Western Nigeria,” Journal of
Tropical Forest Science, vol. 20, no. 3, pp. 193–204, 2008.
[31] D. L. Owen, “The glossary of forestry terminology,” in South
African Forestry Handbook 2000, D. L. Owen, Ed., pp. 724–734,
SAIF, Pretoria, South Africa, 2000.
11
[32] R. G. Lowe, “Volume increment of natural moist tropical forest
in Nigeria,” Commonwealth Forestry Review, vol. 76, no. 2, pp.
109–113, 1997.
[33] V. A. J. Adekunle, “Conservation of tree species diversity in
tropical rainforest ecosystem of southwest Nigeria,” Journal of
Tropical Forest Science, vol. 18, pp. 91–101, 2006.
[34] IIRS (Indian Institute of Remote Sensing), Biodiversity
Characterization at Landscape Level in Western Ghats India
Using Satelite Remote Sensing and GIS, Department of Space
Dehradun, Indian Institute of Remote Sensing, National
Remote Sensing Agency, Dehradun, India, 2002.
[35] C. Konijnenddijk, S. Sadio, T. Randrup, and J. Schipperijn,
“Urban and peri-urban forestry in a development contextstrategy and implementation,” Journal of Arboriculture, vol. 30,
pp. 269–276, 2004.
[36] N. Parthasarathy, “Changes in forest composition and structure
in three sites of tropical evergreen forest around Sengaltheri,
Western Ghats,” Current Science, vol. 80, no. 3, pp. 389–393,
2001.
[37] K.-C. Yang, J.-K. Lin, C.-F. Hsieh et al., “Vegetation pattern
and woody species composition of a broad-leaved forest at the
upstream basin of Nantzuhsienhsi in mid-southern Taiwan,”
Taiwania, vol. 53, no. 4, pp. 325–337, 2008.
[38] E. Duran, J. A. Meave, D. J. Lott, and G. Segura, “Structure and
tree diversity patterns at landscape level in a Mexican tropical
deciduous forest,” Boletin De Sociedad Botanica De Mexico, vol.
79, pp. 43–60, 2006.
[39] A. A. Alvey, “Promoting and preserving biodiversity in the
urban forest,” Urban Forestry and Urban Greening, vol. 5, no. 4,
pp. 195–201, 2006.
[40] A. Balmford, J. L. Moore, T. Brooks et al., “Conservation
conflicts across Africa,” Science, vol. 291, pp. 2616–2619, 2001.
[41] J. Cornelis and M. Hermy, “Biodiversity relationships in urban
and suburban parks in Flanders,” Landscape and Urban Planning, vol. 69, pp. 385–401, 2004.
[42] I. Kühn, R. Brandl, and S. Klotz, “The flora of German cities is
naturally species rich,” Evolutionary Ecology Research, vol. 6, pp.
749–764, 2004.
[43] D. J. Nowak and J. T. Walton, “Projected urban growth (2000–
2050) and its estimated impact on the US forest resource,”
Journal of Forestry, vol. 103, pp. 383–389, 2005.
[44] C. Y. Jim and H. T. Liu, “Species diversity of three major urban
forest types in Guangzhou City, China,” Forest Ecology and
Management, vol. 146, pp. 99–114, 2001.
[45] M. B. Araújo, “The coincidence of people and biodiversity in
Europe,” Global Ecology and Biogeography, vol. 12, pp. 5–12,
2003.
[46] J. C. Onyekwelu, “Biodiversity, socio-economic and cultural
importance of trees in emerging Nigerian urban centres: case
study of Akure city, Nigeria,” in Proceedings of the 15th World
Forestry Congress, Technical Paper, 8 pages, Durban, South
Africa, September 2015.
[47] H. Xu, X. Wang, and G. Xiao, “A Remote Sensing and Gis
Integrated Study On Urbanization with Its Impact On Arable
Lands: Fuqing City, Fujian Province, China,” Land Degradation
& Development, vol. 11, no. 4, pp. 301–314, 2000.
[48] J. S. Miguel-Anyanz and G. S. Biging, “Comparison of singlestage and multi-stage classification approaches for cover type
mapping with TM and SPOT data,” Remote Sensing of Environment, vol. 59, pp. 92–104, 1997.
12
[49] R. R. Gillies and T. N. Carlson, “Thermal remote sensing of
surface soil water content with partial vegetation cover for
incorporation into climate models,” Journal of Applied Meteorology, vol. 34, pp. 745–756, 1995.
[50] R. R. Gillies, T. N. Carlson, J. Cui, W. P. Kustas, and K. S. Humes,
“A verification of the triangle method for obtaining surface soil
water content and energy fluxes from remote measurements
of the Normalized Difference Vegetation Index (NDVI) and
surface radiant temperature,” International Journal of Remote
Sensing, vol. 18, pp. 3145–3166, 1997.
[51] R. W. Miller, Urban Forestry: Planning and Managing Urban
Green Spaces, Prentice-Hall, Upper Saddle River, NJ, USA, 2nd
edition, 1997.
[52] T. Türk and K. Hastaoğlu, “Mobile GIS application in urban
areas and forest boundaries: a case study,” in Proceeding of the
5th International Symposium on Mobile Mapping Technology,
Padua University, Padua, Italy, May 2007.
International Journal of Forestry Research
Journal of
Journal of
Waste Management
Environmental and
Public Health
Hindawi Publishing Corporation
http://www.hindawi.com
The Scientific
World Journal
Volume 2014
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
International Journal of
Ecology
Scientifica
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Journal of
Ecosystems
International Journal of
Oceanography
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Volume 2014
Submit your manuscripts at
https://www.hindawi.com
Journal of
International Journal of
Marine Biology
Atmospheric Sciences
Hindawi Publishing Corporation
http://www.hindawi.com
International Journal of
Geological Research
Volume 2014
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Journal of
Computational
Environmental Sciences
Journal of
Earthquakes
Hindawi Publishing Corporation
http://www.hindawi.com
International Journal of
Journal of
Biodiversity
Hindawi Publishing Corporation
http://www.hindawi.com
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Volume 2014
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Forestry Research
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Geophysics
Applied &
Environmental
Soil Science
Hindawi Publishing Corporation
http://www.hindawi.com
Journal of
Climatology
Volume 2014
Volume 2014
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Advances in
International Journal of
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Environmental
Chemistry
Advances in
Meteorology
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014
Hindawi Publishing Corporation
http://www.hindawi.com
Volume 2014