Assessment of Diversity, Growth Characteristics and Aboveground Biomass of Tree Species in Selected Urban Green Areas of Osogbo, Osun State

Abstract

This study assessed the abundance and diversity of trees, estimated the growth characteristics and determined the aboveground biomass of the trees within three selected green areas, namely Riparian Corridor was abbreviated as Riparian corridor (RC), Industrial sites (IS), and Residential sites (RS) in Osogbo, Southwestern Nigeria. Species Diversity Index, Relative Dominance, and Importance Value Index of trees were also estimated. Trees\' diversity and ranking were determined using the R statistical package. A total number of 124 tree stems were enumerated and (RC), (IS), and (RS) had 49, 38, and 37 tree stems belonging to 27, 18 and 20 species respectively. Albizia zygia (Mimosaceae) was the most abundant species in both RC and IS, while Milicia excelsa (Moraceae) was the most abundant in the RS. Growth variables were recorded as 1.18 m2, 5.01 m2, and 11.06 m2 (basal area), and 13.49 m3, 64.03 m3 and 122.39 m3 (volume) for RC, IS, and RS, respectively. The highest mean aboveground biomass was recorded in the RS (28325.20±7639.57 Kg C ha−1). There was no significant difference (P≥ 0.01) between the aboveground biomass of RC and IS but a significant difference (P≥ 0.01) existed between the aboveground biomass of RC and RS. There is a continuous transition of the urban forest.