Abstract
Allometric relationships for estimating stem volumes of Dalbergia sissoo Roxb. (Sissoo) trees were investigated in monoculture plantations in Bangladesh. The various allometric relationships between stem volume and different dimensions were tested and the coefficient of determination R2 values were used to compare the strength of the relationships. Although the allometric equations were highly significant (P<0.01) there was considerable variation among them as indicated by the R2 values. Our results suggested that tree volume is more correlated with basal area than with simple D (stem diameter at 1.3 m height above the ground). The allometric relationships of stem volume to the tree diameter at 10% of tree height (D0.1) did not improve the allometric strength in comparison with simple D as reported in case of some other tree species. The multiplication of tree height H with D in the allometric equation gives a little improvement in the degree of fitness of the allometric equations. However, for the Sissoo plantations studied the stem dbh alone showed a very strong accuracy of estimation (R2 = 0.997) especially when used as D2. It is concluded that the use of tree height in the allometric equation can be neglected for the species, as far as the present study area is concerned. Therefore, for estimating the stem volume of Sissoo, the use of D2 as an independent variable in the allometric equation with a linear or quadratic equation is recommended. The paper describes details of tree volume allometry, which is important in silviculture and forest management.