Allometric Relationships for Estimating Stem Volume of Rubber Tree (Hevea Brasiliensis Muell-Arg.) in Bangladesh

Abstract

The estimation of stem volume is needed for both sustainable planning of forest resources and for studies on the energy and nutri¬ents flows in ecosystems. Tree volume equation provide to the tree biomass and carbon estimation in non-destructive way. The aim of this study is to developed allometric relationships for estimating stem volumes of rubber tree (Hevea brasiliensis Muell-Arg.) were investigated in monoculture plantations of Bangladesh. The various allometric relationships between stem volume and different tree dimensions were tested and the values of coefficient of determination (R2) were used to compare strength of these relationships. Although the allometric equations were highly significant (P<0.001), there were considerable variations among them which was also indicated by R2 value. The results suggested that tree volume is more correlated with simple G (stem girth at 1.3m height from ground). The allometric relationships of stem volume to various dimensions such as G2 and LnG did not improve the allometric strength in comparison to simple G which was also reported for some other tree species. The multiplication of tree height, H and girth, G in the allometric equation gives a little improvement to consider the degree of fitness. However, in this plantation, girth at breast height, GBH only showed a very strong accuracy of estimation (R2=0.953) especially when used variable G. Therefore, for stem volume estimation, it is recommended to use independent variable G2 in the allometric equation. The paper describes the tree volume allometry in details which has significant importance in the field of silviculture and forest management.