Characterizing Measures of Aboveground Biomass Parameters of Irvingia gaboneensis (Bush Mango) and Rainforest in Isoko Region, Nigeria

Abstract

This research characterised measures of aboveground biomass of isolated Irvingia gaboneensis stands within Isoko South Local Government Area’s rainforest, Nigeria. The design of the study was based on quasi experimental approach. The region was divided into 10 based on the existing major communities using stratified sampling technique. From each community, an isolated I. gaboneensis stand was chosen while the adjacent mature rainforest served as control thus, gave a total of 20 sampling sites. Data collected were tree heights (TH) and diameters at breast height (DBH) which were easily obtained through quadrant (10metre x 10metre) approach. Measurement and methods of trigonometry were employed in the determination of TH, while measurement using tape was employed to measure the tree DBH. The data were analysed with the use of graphs, mean, standard deviation (SD), coefficient of variation (CV), t-test and regression statistics. Findings showed that: The mean, SD and CV for the TH were 28.57m, 2.08m, 7.28% for the stands of I. gaboneensis; and 34.50m, 1.17m, 3.39% for adjacent rainforest trees (ART). The mean, SD and CV values for tree DBH were 0.43m, 0.02m, 4.65% for the stands of I.  gaboneensis; and 0.73m, 0.01m, 1.37% for the ART. With t-value and p-value of 6.9810 and 0.0000 for TH; 11.9940 and 0.0000 for DBH, the differences in the aboveground biomass parameters between I. gaboneensis and ART are significant at 95% alpha level. Height of I. gaboneensis correlated weakly with DBH; while the relationship between TH and DBH is not significant at 95% alpha level, for I. gaboneensis and RF. The aboveground parameters of the standing I. gaboneensis shows that it supports effective productivity and functioning of the RF ecosystem thus, its conservation is necessary.