Specific gravity and carbon content of woody species in lowland moist forest and savanna vegetations of parts of Osun State, Nigeria

Abstract

This study assessed the wood-specific gravity (WSG), carbon content and above-ground biomass (AGB) of some woody species in forest and savanna vegetations of Osun State, Nigeria. Carbon concentration in the AGB was determined by oven-drying each woody stem core at 80o C to constant weight prior to analysis. WSG of the stem cores of tree species was determined from the oven-dry wood mass and green volume. WSG was lowest in Newbouldia laevis (0.20) and Piliostigma thonningii (0.38) in forest and savanna, respectively while Afzelia africana had the highest WSG in forest (0.89) and savanna (0.87) vegetations. Carbon content in AGB ranged from 40.0% (Oncoba spinosa) to 53.3% (Celtis zenkeri) in the forest, but it varied from 41.0% (Daniella oliverii, Ficus asperifolia, Gliridia sepium, Rauvolfia vomitoria) to 56.00% (Parkia biglobosa) in the savanna. In the forest, Mallotus mildbraedii (39.49 kg) and Funtumia elastica (2428.93 kg) had the lowest and highest AGB in the savanna vegetation; Cnestis ferruginea (38.16 kg) and Vitellaria paradoxa (1530.62 kg) had the highest and the lowest AGB, respectively. The study showed that the specific gravity of the woody species, AGB and carbon content varied within and among species in forest and savanna vegetations.