Evaluation of Aboveground Biomass and Carbon Stock Content of Seven Most Abundant Tree Species in Oluwa Forest Reserve, Ondo State, Nigeria

Abstract

Climate change has become a topical issue in the recent time. Hence, several research efforts are geared towards mitigating the effects especially in Nigeria where deforestation rate is alarming. Carbon sequestration potentials of different tree species has been suggested as mitigating factor of climate change. Hence, the objective of this paper is to evaluate the aboveground biomass (AGB) and carbon stock (CS) content for seven most abundant trees species in Oluwa forest reserve, Ondo State Nigeria using systematic line transact, twenty temporary sample plots (25m x 25m) were demarcated. All tree species (diameter at breast height ≥ 10cm) were identified to species level and the seven most abundant (Funtumia elastica, Celtis zenkeri, Ricinodendron heudolotti, Diospyros crassiflora, Berlinia grandiflora, Picralima nitida and Buchholzia coriacea) selected. The tree height, diameters at the base, middle and top of each selected species were measured. Tree Volume (TV), AGB and CS were estimated and Wood Density (WD) determined following standard procedures. It was observed that Ricinodendron heudolotti had the least WD (360kg/m³) but highest TV, AGB and CS (4.7547 m³, 1711.683kg and 855.8415kg), respectively. Diospyros crassiflora had the highest WD (670kg/m³) but the least TV, AGB and CS (0.1480 m³, 99.191kg and 49.5953kg), respectively. This revealed that TV is an important determining factor of AGB.  This study shows that high WD alone does not result in high AGB but the TV must equally be high. The more a forest tree is left to mature, the more the AGB and consequently, the amount of carbon that can be sequestered from such forest.