ABSTRACT

Aboveground biomass refers to the total mass of living plant material present above the ground. Carbon sequestration aims to reduce atmospheric CO₂, a key driver of climate change. By capturing and storing this greenhouse gas, the impact of global warming on our planet's temperature can be reduced. This study aims to estimate the above-ground biomass and sequestering potential of the mixed forest stand in University of Benin for the effective management of the site. The aboveground biomass and carbon sequestration were estimated from 173 trees. The total amount of aboveground biomass is 148292.428kg/ha. Three allometric equation were used but the best one based on Model 3 – y = exp(lna+b·lnDBH+c·lnH) emerged as the most reliable predictor of AGB within the framework of this study based on its superior explanatory power R²  (0.541), smaller prediction errors RMSE (1836.224), optimal balance between goodness-of-fit and Model 3 complexity AIC (1045.807) and low MAB (908.935) and RSE (1825.424) as compared to Model 1 – y = exp(lna+b·lnDBH) and Mode1 2 – y = exp[lna+b·ln(DBH²·H)] indicating a R² value of 0.423 and 0.238, a RMSE value of 8040.462 and 2343338612.546, an AIC value of 1047.923 and 1048.888. a MAB value of 2371.456 and 209057076.789 and a RSE value of 7993.304 and 2329594572.519 respectively incidating that Model 1 -  y=exp(lna+b·lnDBH) was a close competitior. In Model 3 - y = exp(lna+b·lnDBH+c·lnH) the coefficient for ln(DBH) (29485.737) indicates a positive value which suggests that as DBH increases, Y increases exponentially and it is highly significant (p-value = 0.000), while (82.846) is a Coefficient for ln(H) which indicates a much less pronounced effect of height on Y compared to DBH and the coefficient of ln(H) is not significant (p-value = 0.401). Both diameter at breast height (DBH) and height (H) were highly significant contributors (p-value < 0.001) in Model 3 - y = exp (lna+b·lnDBH+c·lnH). The total amount of carbon sequestrated were 342555.51kg/ha and which shows that the UNIBEN uneven aged plantation has the potential to store an equivalent of CO₂ emissions of an estimate of 571 people in Nigeria. The Africa Carbon Markets Initiative (ACMI) estimated that Nigeria itself can generate as much as 30 million carbon credits every year by 2030, using a price of $20 dollars per credit, which indicates that this plantation is worth am estimate of $6800 carbon credits which is about N92m. This study shows promise for effectively capturing carbon dioxide and mitigating climate change in Nigeria and recommends developing species-specific allometric equations, exploring remote sensing integration, and promoting sustainable forestry practices to improve aboveground biomass estimates and carbon sequestration in UNIBEN-like plantations.