Comparison of Allometric Models For Biomass Prediction in a Mixed Forest Stand, Edo State, Nigeria

Above and below ground biomass refers to the total mass of living plant material present above and below the ground. In this study, three (3) allometric models were used to estimate biomass and these models were adjudged based on five (5) test fit statistics. A total of one hundred and seventy-three (173) trees were used in the estimation of biomass in this study. The total amount of aboveground biomass is 148292.428kg/ha. Model 3 with the expression Y = exp(lna+b·lnDBH+c·lnH) emerged as the best predictor of AGB & BGB within the framework of this study based on its superior explanatory power R² of 0.541, smallest values for RMSE (1836.224), AIC (1045.807), MAB (908.935) and RSE (1825.424) respectively as compared to Model 1 and Mode1 2 which had a R2 values of 0.423 and 0.238, RMSE of 8040.462 and 2343338612.546, AIC of 1047.923 and 1048.888, MAB of 2371.456 and 209057076.789 and a RSE values of 7993.304 and 2329594572.519 respectively. Model 1 with the expression Y = exp (lna+b·lnDBH) was a close competitor. In Model 3 the coefficient for ln(DBH) was (29485.737) indicates a positive value which suggests that as DBH increases, Y increases exponentially and it was highly significant (p-value = 0.000), Both diameter at breast height (DBH) and height (H) were highly significant contributors (p-value < 0.001) in Model 3 making it the best model in estimation of total biomass for this study.