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Structural diversity of tree stems of Elephant Camp Natural Forest in Omo Forest Reserve
Environmental Sciences Proceedings, 2020
Tree size diversity is an indicator for biodiversity values of a forest. Microsite conditions of forest determine the survival and growth of tree. However, the contribution of variable habitats to tree size hierarchy and segregation is poorly understood. Tree size variation in a population is caused by different competition mechanisms. Therefore, size distribution and spatial pattern of trees can identify the process governing resources utilization in the forest. The objective of the study was to investigate tree stems structural diversity of Elephant Camp natural forest in Omo Forest Reserve. Three and four 0.09ha sample plots were established in Riparian (RF) and Old-growth forests (OF) of Elephant camp, respectively. The tree stems (Dbh≥5cm) were identified to species level and enumerated within each plot and stem density was computed. The diameter-at-breast height (Dbh) was measured with diameter tape. Species diversity was assessed using Shannon-Weiner (H´) and Simpson indices (1-D´) while size inequality was assessed using Gini coefficient (GC), Coefficient of Variation (CV), H´ and I-D´. The performance of single two-and three-parameter Weibull models were evaluated; Kolmogorov-Smirnov (K-S) Chi-Square (χ 2), Root Mean Square Error (RMSE), Bias and Coefficient of determination (R 2). Data were analysed using descriptive statistics. A total of 27 and 24 tree species were identified in RF and OF, respectively. Stem density of RF was significantly higher than OF. The value of species diversity (H´, 1-D) and Evenness (E´) were higher in OF than RF while richness (Margalef and number of species) was higher in RF than OF. The Dbh were 38.30±21.4 and 42.87±19.2 cm in Riparian and Old-growth forests, respectively. Diameter distributions of both forests were positively skewed and expressed exponential pattern. The forest types of Elephant Camp natural forest comprise the same size frequency shape but different proportion of tree sizes and structural diversities.
International Journal of Agriculture and Forestry, 2022
Spatial species diversity and size inequality contribute to maintenance of tree species diversity in tropical forests. Coexistence of tree species requires interactions within and between spatial species and size diversity. However, elevation gradient has significant impact on growth and species interactions. Failure of most conservation efforts is due to inability to identify and maintain coexistence mechanisms existing in the forest. Understanding the contribution of elevation gradient to coexistence of tree species will improve conservation efforts and terrestrial carbon budgeting. Therefore, association between tree diversity and size inequality on elevation gradient of Elephant Camp Natural Forest was investigated. Eight (30m x 30m) plots were systematically demarcated on 1km line transects in each identified elevation (Hilltop and Valley-Bottom stands). Trees diameter-at-breast height (dbh) were enumerated and identified to species level. Tree dbh was measured and density estimated. Tree species diversity (Shannon-Weiner, Simpson and Margalef indices) and size inequality (Gini coefficient, skewness and Coefficient of variation) were computed. Stem volume and biomass were computed and converted to biomass carbon. Data collected were analysed using descriptive, correlation analysis and principal component analysis. Tree density varied from 435/ha to 767/ha. There was positive correlation between Skewness and Gini coefficient in Hilltop stand and negative correlation between Skewness and Simpson index in Valley-Bottom stand. The measures of tree size inequality and species diversity were strongly associated with each other in Valley-Bottom stand and not in Hilltop stand. Structural diversity and species diversity determined the competitive interaction among tree communities in Hilltop and Valley-Bottom stands, respectively.
Tree Species and Size Diversity of Akure Strict Nature Reserve, Nigeria
American Journal of Agriculture and Forestry, 2023
Size and species structures control the natural mechanisms maintaining high structural diversity. Use of size inequality and species diversity measures singly for conservation decisions brings about inconsistent results. Therefore, most conservation efforts fail due to lack of understanding of mechanisms promoting coexistence of tree species. However, relationship between size inequality and species diversity indicates the natural mechanism promoting coexistence of high species diversity. Therefore, this study investigated the relationship between tree size inequality and species diversity in Akure Strict Nature Reserve. Eighteen and twelve plots (30m × 30m) were laid on parallel transects of 3.60km long and 50m width in Old-growth and Riparian forests, respectively. Trees with diameter-at-breast-height (dbh) ≥ 10cm were counted and identified to species level. Tree diameter at base, middle and top and total height were measured using girth tape and Relaskop. Tree species diversity (Shannon-Weiner; Simpson; Margalef indices) and dbh inequality measures (Gini coefficient, Gini; Coefficient of Variation, CV; Skewness Coefficient, Skewness) were computed and compared. Stem biomass were computed and converted to carbon stock. Data were analysed using descriptive, and correlation analysis at α 0.05. Fifty-five (56) tree species representing 17 families were found in the forest. Species diversity indices were higher in Riparian while size inequalities in Old-growth forests. GC correlate with Shannon-Weiner (r=0.54; n=18, p≤0.018) and Margalef (r=0.473; n=18, p≤0.04) in Old-growth while GC correlate with CV (r=0.716; n=12, p≤0.09) in Riparian forests. The size inequality measures were strongly related with each other in Riparian while species and size inequality measures were strongly related with each other in Old-growth forests. The carbon stocks of Old-growth and Riparian forests were 117.21Mg/ha and 43.47Mg/ha, respectively. Triplochiton scleroxylon and Bridelia micrantha contained highest carbon stock in Old-growth and Riparian forests, respectively. Asymmetric mode of interaction in the absence of competition shows competition for below-ground resource, especially presence of moisture and nutrient gradient. Size inequality among different and within the same species determined coexistence tree communities in Old-growth and Riparian forests of Akure Strict Nature Reserve, respectively.
Diversity and Volume Assessment of Tree Species in the Tropical Forest at Obanla, Akure, Nigeria
Asian Journal of Research in Agriculture and Forestry , 2020
This study focused on the assessment of tree species diversity and abundance at The Federal University of Technology, Akure Tropical Forest Obanla. The research was carried out from May, 2019 to September, 2019. Complete enumeration sampling was adopted for the data collection and all trees with diameter at breast height (Dbh) above 0.1 m were identified and measured. Other tree growth variables, such as diameter at the base (db), diameter at the middle (dm), diameter at the top (dt) and the total height were all measured for volume estimation. Ricinodendron heudelotii Hd the highest number of stems (13), so it was the dominant tree species.The result shows that mean tree volume ranges from a minimum of 0.26 m 3 for Olalaceae family, to a maximum of 77.70 m 3 for Euphorbiaceae family. Ceiba pentandra of Malvaceae family had the highest mean volume (14.62 m 2) while the lowest was recorded for both Khaya senegalensis and Newbouldia laevis with a volume of 0.13 m 2. The family of Euphorbiaceae was regarded as the dominant family in the natural forest with 26 tree species which is the highest in this study and with the highest volume (77.70 m 2). Shannon Wiener diversity index and species equitability index according to Pielou's of 3.24 Original Research Article Olawoyin et al.; AJRAF, 5(4): 11-19, 2020; Article no.AJRAF.56230 12 and 0.92 were respectively obtained for the study area. This study revealed the efficacy of an undisturbed natural forest in in situ conservation. Active regeneration can be carried out for proper stocking of the forest so has to make it a potential biodiversity hotspot.
COMPARISON OF WOODY SPECIES DIVERSITY AND POPULATION STRUCTURE ALONG DISTURBANCE GRADIENT IN BABILE ELEPHANT SANCTUARY, ETHIOPIA, 2022
The study was conducted at Babile Elephant Sanctuary (BES), to identify and document the list of woody species, and to analyze the diversity, richness, evenness, and population structural status of woody species. The diversity of plant species and population structure of woody species were analyzed from 60 quadrats, each with 20 m x 20 m for trees and 5 m x 5 m for shrubs and climbers, using systematic sampling methods with three levels of disturbances regime, namely, low disturbed (LD), moderately disturbed (MD) and heavily disturbed (HD) sites. Vegetation parameters such as diameter at breast height (DBH), richness, evenness, and density of woody species were recorded. Shannon Weiner Diversity Index was used to analysis vegetation diversity and evenness. A total of 61 woody species were identified in the study area that falls within 29 families and 38 genera of which 50.8 % were shrubs, 39.3 % were trees and the rest 9.83 % were climbers. Fabaceae was represented by the highest number of species (14 species = 22.90). The highest plant species richness was recorded from the low disturbed sites, followed by moderately disturbed and heavily disturbed sites respectively. The population density of vegetation was significantly higher in the MD site, followed by the LD site. The total basal area of LD, MD, and HD were 27.2, 19.8, and 11.2 m2/ha, respectively. LD site had significantly (P= 0.04) highest Shannon’s diversity index value (3.21) than the others two disturbance levels. This result suggests that the consequence of human-induced disturbance on woody species diversity and population structure appeared to be negative depending on the type and intensities of the disturbances.
Ecological and Structural Analyses of Trees in an Evergreen Lowland Congo Basin Forest
Floristic inventory and diversity assessments are necessary to understand the present diversity status and conservation of forest biodiversity. Studying the variation height-diameter woody provides insight into the general characteristics of the trees diversity pattern. This study mainly focuses on aimed to assess the effectiveness of trees diversity and structure in two study sites. The study was conducted at Ipendja evergreen lowland moist forest in northern Republic of Congo. The sampling design was systematic consisted of parallel transect 1 or 2 km part, and divided into consecutive rectangular plots, each 5000m 2 (25 x 200 m, i.e. 0.5 ha). Within eight plots censuses, all trees with a DBH ≥ 10 cm were identified and measured. A total of 1340 trees has been recorded belonged 145 species and 36 families (n = 607 and n = 733, respectively in Mokelimwaekili and Sombo sites). The results show that the leading botanical families were Sapotaceae follows by Euphorbiaceae, Meliaceae, Caesalpiniaceae, Sterculiaceae, Annonaceae and Rubiaceae. The most representative species were C. mildbraedii, S. kamerunensis and P. oliveri, i.e. 62.06%, 30.34% and 28.27% respectively, demonstrated that they were the leading dominant species of this forest ecosystem. Shannon index were 4.29 bits for Mokelimwaekili and 4.22 bits for Sombo. While Pielou's evenness index was between 0.88 and 0.90, respectively for the Mokelimwaekili and Sombo sites. The similarity coefficient for Jaccard was 62% and 58% for Sorensen. There are highlight variations in tree diversity indices across sites and plots in Ipendja forest.
Journal of Applied and Natural Science, 2021
Forests are the main repository of biodiversity and play an important role in maintaining the ecological balance of nature. The status of species diversity reflects the health of the ecosystem. Therefore, the information on variation in the flora, for example, species composition, diversity and the basal area within any ecosystem like the forest of Mizoram University campus, Tanhril village, Aizawl would be important in understanding the forest wealth of the campus. Keeping in view, the study was analyzed the composition and diversity of Mizoram University campus by laying 16 (10 m ×10 m) quadrats at random locations during 2015-2016. A total of 35 tree species belonging to 30 genera and 22 families were recorded in the forest communities of University Campus. Aporusa octandra was the most dominant tree species with maximum 31.50 importance value index (IVI), 3.29 Shannon diversity index (H0) and 6972 Simpson’s index (D) followed by Castanopsis tribuloides (28 IVI, 0.22 H0 and 525...