Allometric equations for estimating aboveground biomass for Paulonia trees (Paulownia fortunei) in the Dr. Bahramnia Forests Plan of Gorgan

The aim of this research was to pick out the most relevant allometric equations to estimating aboveground biomass of Paulownia Fortunei species in Dr. Bahramnia Forestry Plan. Totally, 16 Paulownia Fortunei trees were cut, and then they were transformed and weighted. After that, to determine the coefficient of dryness this species, some samples were taken from the different parts of trunk, branches, leaves and fruits. The samples were dried in Oven at 110 ° C for 48 hours (for trunk and main branches) and 70 ° C for 48 hours (for other sections). Using 29 allometric equations, the relationship between aboveground biomass as dependent variable and D.B.H, height and dry wood density as independent variables were analyzed. The results indicated that among the various models, Model No. 21 was used using combination of two variables of diameter at breast height and height as independent variables with an explanation coefficient of 0.947 and the mean square error of 26.77% of the best fit. The results showed that the model number 21 that used combination of diameter at breast height and tree height as independent variables were the best prediction for aboveground biomassof Paulownia Fortunei species, with R2 0.947 and RMSE% -26.07%. The result was not improved by adding dry density as other independent variable along with diameter at the breasts and height trees. In sum, among the all investigated independent variables, the variable of diameter of the breasts height showed the most fit on total biomass of Paulownia Fortunei species.