Allometric equations to predict stem volume of important north-western himalayan tree species in Himachal Pradesh
Aditi Sharma, DP Sharma, Jaya Shree Behera
The study was conducted in Kotgarh Forest Division of Himachal Pradesh to develop allometric models for estimation of tree volume where tree species viz., Pinus roxburghii, Pinus wallichiana, Cedrus deodara, Abies pindrow, Picea smithiana and Quercus leucotrichophora were studied. Various linear and non-linear relationships developed taking DBH and tree Height as predictor variables individually. Out of linear and non-linear function, the power functions were best fitted for all the species with significant adjusted R2 with diameter at breast height as independent variable as: Pinus wallichiana (0.99), Picea smithiana & Pinus roxburghii (0.98), Abies pindrow & Cedrus deodara (0.97), Quercus leucotrichophora (0.96). Similarly, adjusted R2 valuesfor stem volume with tree Height as independent variable were as: Pinus roxburghii (0.95), Pinus wallichiana (0.93), Cedrus deodara (0.86), Abies pindrow & Picea smithiana (0.87), Quercus leucotrichophora (0.75). However, Model comparison and selection was based on adjusted R2, chi-square test of goodness of fit and thereafter-using Theil’s-U statistics were cross-validated to ensure further adequacy. The allometric models developed can be utilized for future estimation of tree volume and biomass carbon of species under study as it fit the data well and gives user the opportunity to predict stem volume from the DBH and tree height for these temperate species. The role of allometric equations in volume estimation has thus been highlighted through the findings of this study.