EVALUATION OF GROWING STOCK, BIOMASS AND SOIL CARBONS AND THEIR ASSOCIATION WITH A DIAMETER: A CASE STUDY FROM A PLANTED CHIR PINE (PINUS ROXBURGHII) FOREST

The statistical association between the capacity for carbon sequestration and planted Pinus roxburghii tree diameter classes are not recorded in Pakistan.Through the forest inventory approach, a comprehensive study was conducted in planted P. roxburghii forest in Pakistan's Swat Hindu Kush area to determine the carbon stock (CS) of a live tree, forest floor and soil (SOC) and their association with three diameter classes (6-22, 23-40, 41-60 cm).The results specified that stem density had a polynomial relation with the diameter (R2 = -0.54),while tree height had a linear relationship with the diameter (R2 = 0.73).Association of tree volume, stem biomass, total tree biomass with basal area against diameter classes were positively linear [(R2 = 0.86, 0.80, 0.80) for DBH (41-60 cm)].As the diameter increases, grass CS reduced while litter and deadwood CS increased significantly.Association of diameter classes with (SOC) at various depths was negatively linearly correlated [R2 = -0.99;for DBH (41-60 cm)], while the topsoil layer (0-20 cm) SOC rose significantly with increase in diameter class.With the increase in tree diameter, the tree age increased definitively (R2 = 0.99).An increase in diameter class ultimately increased CS amount, and the trend was as follows: live tree > soil > forest floor.This study significantly demonstrated the diameter relationship with the tree, forest floor and soil CS of planted P. roxburghii forest.