Determine the most suitable Allometric equations for Estimating Above-ground Biomass of the Juniperus excelsa

Today, modeling and determination of allometric equations of forest trees, especially Junipers trees, are very important for determination of biological status and carbon storage capacity of forest species. The aim of this study was to determine the most suitable allometric equations for estimating the biomass of leaf, sub branch, main branch, trunk, and biomass of total Juniperus excelsa trees in Chaharbagh region of Golestan province. For modeling, at least 3 trees were selected in each diameter class for harvesting leaf and branch samples. A total of 35 sample trees were harvested and in the laboratory after weighing and drying samples, the biomass of leaf, branch, trunk and total was calculated. Allometric equations were obtained based on power, exponential and polynomial regression models. For validating the models, the criterion of determination coefficient, standard deviation of fitted model, regression analysis, and compliance with the distribution of residual values from normal distribution were used. The results showed that independent variables, diameter at beast height, crown surface and mean diameter of the crown produced equations with better modeling indices. Also, the power and polynomial models of the exponential model were more appropriate. The correlation coefficient obtained from regression models showed that these allometric equations are suitable for estimating the biomass of Junipers trees in the study area.