Aboveground biomass estimation of small diameter trees of Carpinus betulus, Fagus orientalis and Parrotio persica using power regression model

Today، measurement of the forest biomass is important from different aspects. The biomass estimation of small diameter trees as missing part of measurements is significant. The main objective of this study is to develop allometric equations for estimating the stem، branches، leaf، bark and total biomass of small diameter trees including Carpinus betulus، Fagus orientalis and Parrotio persica. To achieve this purpose، 10 intact trees from each species that have 2-8 cm diameter were randomly selected and collar diameter، diameter at breast height، diameter where crown started، crown diameter and height were measeured. Then trees were felled down and different parts were weighted. One sample from each part was transferred to lab and percent of dry weight was calculated. The most appropriate equations for estimating different parts of the trees biomass were selected by using power regression model. The results show that among the variables، diameter at breast height is the most appropriate estimator for estimating woody parts biomass of small diameter trees in all three species and equations can be produced by heigh R2. But، regression models for non-woody parts of small diameter trees can not be produced by sufficient accuracy.