RELATIONSHIP BETWEEN STEM BIOMASS WITH HEIGHT AND DIAMETER OF Pinus caribaea IN THE YAGIRALA FOREST RESERVE

Abstract

The biomass is an important measurement in commercial forestry maintained to producepulp, paper, chips, fuel wood products etc. The estimation of biomass of the tree is not aneasy task and a few studies were carried out so far on this problem.

The present study was conducted in 25 years old pine plantation in Yagirala ForestReserve, situated in low country wet zone. According to the geographical differences ofthe plantation, stratified random sampling was carried out and two 0.05 ha circular plotswere established in each stratum. Altogether 6 plots were used for the data collection.The diameter at the breast height (dbh) and total height were measured for all the trees inthese plots.

Biomass of the tree was estimated by extracting core samples at the breast height and midheight of the tree. The density of the core samples was estimated using oven dry weightand green volume of the core samples. When tested, there was no significant differenceof density along the stem. Therefore stem biomass was estimated using the density atbreast height. Also there was no significant density difference between three sites.

The regression analysis was used with pooled data to find out the relationship betweenthe stem biomass with the tree diameter and height. Using variables of stem volume (W),total height (h), diameter at breast height (d) and their transformations, several modelswere developed. The best model was selected by testing for the R2 value, standardresidual distribution, modelling efficiency and bias. The best relationship for the stembiomass, total height and diameter at breast height was given by the following equation,which has R2 value of90.3.

logW = -0.917 + 2.081ogd + O.0195h