Biomass and carbon stock estimation of five selected tree species in a secondary forest at Obafemi Awolowo University Campus, Ile-Ife, Nigeria

Biomass and carbon stock of five treespecies were investigated in a secondaryforest in Ile-Ife, Nigeria in order to assessthe contribution of individual tree speciesto above and below ground biomass, andcarbon stock in the forest. Fifty individualtrees each of Celtis zenkeri, Funtumiaelastica, Holarrhena floribunda, Sterculiatragacantha and Newbouldia laevis weresampled. The diameter at the base (at theground level), middle (approximately halfof the tree height), top (diameter of the tipof the tree) of the trees as well as at breastheight; height of individuals of eachspecies ≥ 10 cm DBH were measured.Above ground biomass was calculated as aproduct of stem volume and wood basicdensity while carbon stock was determinedas the product of dry weight and anassumed carbon content of 50% of the treebiomass while below ground biomass wasestimated using root:shoot ratiorelationship. Results showed significant (p< 0.05) differences in biomass and carbonstock between the tree species. The orderof biomass accumulation and carbon stockwas Celtis zenkeri > Holarrhenafloribunda > Funtumia elastica >Newbouldia laevis > Sterculiatragacantha. The lower DBH size class(21-30 cm) had the highest biomasscontribution in the species. The studyshowed that the forest was generallycharacterized by small individuals and alsoprovided information that will enhanceprediction of biomass and carbon stockdetermination in tree species