ASSESSMENT OF TREE BIOMASS CARBON STOCK OF A SUBTROPICAL SCRUB FOREST, SOAN VALLEY PAKISTAN

In Pakistan the lack of development for local allometric equations has led to the use of simple generic volume equations which may generate errors in forest carbon estimates This research was designed to quantify tree carbon stock and check the robustness of the existing models against local allometric models.The study was conducted in Hayat-ul-Mir subtropical scrub forest in Pakistan comprising of a bi-climax community of Acacia modesta Linn. and Olea ferruginea Royle.Tree measurements were taken in 47 plots of 0.04 ha and biomass carbon estimates were made using local allometric, existing generic pantropical model and i-Tree Eco tool.No significant difference in biomass carbon (ton/ha) was found between local (8.53) and pantropical models (8.68) for A. modesta and between the three models for O. ferruginea (10.92, 11.91 and 11.87 for local allometric, pantropical model and i-Tree Eco, respectively). All models fitted data well (p< 0.001), whereas the pantropical model incorporating three biophysical variables better predicted biomass and was found more robust for both species based on AIC, BIC, RMSE and R-2 adj. values. In the absence of local models, the pantropical model can provide better biomass estimates for deciduous and evergreen subtropical species to report carbon stock.