By: Komolafe O. O.; Ige P. O.;
Abstract:
Assessment of tree species composition, richness and diversity analyses were carried out in the International
Institute of Tropical Agriculture (IITA) forest with the aim of developing an efficient management plan for
promoting biodiversity conservation in the study area. Limited research work has been done on diversity with an
examination of what causes a reduction in the floristic composition in many tropical forests. Hence, this study was
conducted to assess biodiversity and to give an in-depth understanding of the status of the forest and the reasons
for the endemic tree species being currently endangered. Data used were collected from IITA forest Ibadan, Nigeria.
Simple systematic line transect of four parallel transects of 200m apart were used for plot laying. Sixteen sample
plots of 25m × 25m were laid for data collection, all trees with Diameter at Breast Height (dbh) ≥ 10cm were
measured to determine No the number of stand per hectare(Ni/ha), Quadratic mean dbh per hectare (DQ/ha) and
Volume per hectare (V/ha). Trees were sorted into species, families, frequency of occurrence, height and DBH
classes. The DBH, TH, N/ha, DQ, TSC, V and CD ranged from 10– 170cm, 7.7m – 38.1m, 96 – 704, 18.047 –
52.655cm, 22 – 225%, 0.003 – 24.676m3 and 3 – 13.7m, respectively. The stand comprises of 389 stem ha-1belonging
to 43 species in 19 families were recorded from this study. Apocynaceae family had the highest number of individual
species of 87. The most abundant family was Fabaceae which comprises of 10 species. Funtumia elastica had the
highest important value index of 11.03. The forest had a Shannon wiener and margalef index of 3.037 and 58.019,
respectively. Moraceae family had the highest basal area per hectare (7.62m2
). Fabaceae family had the highest
numbers of family Important Value Index (FIVI) of 60.21 and highest Shannon wiener diversity index of 0.65.
Inverse J shape pattern was observed in the DBH distribution curve. The lowest DBH class (10 – 20cm) had 218
species (56.04%), while the highest DBH class (≥100) had 4 species (1.03%). The damages observed on the tree in
the study area showed that 4% of the trees were affected by diseases, while 1% affected by anthropogenic activities
and the tree that are healthy ones were 89%. This implied that the forest could be in a healthy state and protected
for biodiversity conservation.
Keywords: Biodiversity; Tree growth characteristics; Tree damages; IITA;
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