Effect of forest structure and composition on carbon stocks in the primary and secondary forests of Budongo Central Forest Reserve, Western Uganda

Abstract

Tropical forests provide the largest terrestrial carbon stocks around the world, yet these carbon reserves fluctuate as a result of natural and man-made disturbances. In order to help efforts to conserve tropical forests, and enhance their carbon sequestration role, accurate estimates of forest carbon are critically needed. This study quantified aboveground carbon (AGC) stocks in the primary and secondary forests of Budongo Central Forest Reserve in relation to the forest structure. Data on tree diameter for 32, 20m x 20m plots in the primary, and the secondary forest, together with allometric equations, to estimate above ground carbon were used. Trees of diameter at breast height (DBH) ≥ 10 cm and saplings DBH ≥ 5 cm were measured. The study also quantified tree species richness and the number of stems in each of the forest types. The primary forest had 337 stems /ha, and 40 species. The secondary forest consisted of 290 stems/ha distributed into 55 species. Total estimated AGC in the primary forest was 171tonnes/ha, and 82.9 tonnes/ha for the secondary forest. The undisturbed forest was less species rich, but had more stems per ha and high biomass and carbon overall, emphasizing the need to better manage tropical forests, control encroachment on these forests, if we are to benefit from their carbon sequestration and climate change mitigation services.