Volumetric tree growth models for aboveground biomass estimation of Pinus kesiya and Toona ciliata in Northeast India

Pinus kesiya and Toona ciliata are widely distributed commercially important tree species in Northeast India. However, precise tree volume estimation is absent; therefore, the estimation of biomass and carbon stock of these tree species is difficult. The present study attempted to bridge this gap by developing non-destructive allometric models for estimating the biomass and carbon stock of these trees. Allometric models were developed by selecting 46 trees of P. kesiya and 54 trees of T. ciliata from different diameter classes covering the entire girth range. For developing tree volume and biomass models in this study, total tree height (H), diameter at breast height (DBH) and various tree heights for both species were measured. The performance of these models was assessed based on the coefficient of determination (adjusted R2) and Akaike's Information Criterion (A.I.C.), besides many other statistics. The best-fit model of P. kesiya was: lnAGB = −3.7268 + 1.5908 (lnD*H) and for T. ciliata was: lnAGB = −2.0311 + 1.4858 (ln D*H*WD). The developed allometric models of P. kesiya and T. ciliata may be suitable for estimating the species-specific biomass and carbon stock of these species. The study will be useful in estimating the carbon stock and sequestration potential of the region, which will help in the assessment of global carbon cycling.