Density of basic components of above-ground biomass of poplar clones.

Abstract

The experimental material was obtained from 20 trees of Robusta clone and 21 trees of I-214 clone on the territory of Slovakia. Samples of wood and bark were taken from three parts of stem and two parts of tree crown. Volume of the green samples was determined in calibrated graduated cylinders with precision of 1 ml and their dry weight with precision of 0.01 gram. Influence of 7 predictors, of them 3 factors (biomass fraction, location on tree and clone) and 4 variables (site index and age of stand, height and diameter of tree) on density of biomass fractions (wood, bark and small-wood) was analyzed by the generalized analysis of variance. Statistically significant influence appeared for all predictors except for height and diameter of tree. Average density of all biomass fractions were approximately in the range of 350-470 kg.m-3 and variation coefficients in the range of 4-13 %. Statistical tests showed that Robusta clone has higher wood density than I-214 clone. These differences are approximately 15 % on stem base and in middle stem, 10 % on crown part of trees and 4 % for small-wood. Differences in bark density between clones were not confirmed.