Basic density of the wood from Eucalyptus species grown in Rwanda
No Thumbnail Available
Date
1982
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Dar es Salaam
Abstract
Basic density of the wood from Eucalyptus matidenii, Eucalyptus microcorys and Eucalysaligna grown in Rwanda was studied. The objectives of the study were:To provide information on the variation in basic densities of the species.To provide information on the variation in basic densities within and between trees of the species. To find whether a relationship existed between basic density and tree age and site.To compare the basic densities of the three species from Rwanda with those of the same species grown in other countries. Each of the three species was sampled at Butare, Gisenyi and Musha, sites which are located in different geographic regions. Three 5 cm thick discs were cut from each tree, one at breast height, one at 33 per cent and one at 66 per cent of total tree height. A strip of 2 x 2 cm cross section was extracted from each disc from bark to bark through the pith. The radial strips were then cut into two pieces through the pith and each of these pieces was finally divided into three equal length sections which were used as final samples for the laboratory measurements. Basic density was calculated from oven dry weight and green volume of the samples. The main results from the study are: There were no significant differences between sites. Although the effect of age on basic density could not be confirmed due to intervening factors, tree average basic densities from younger stands seemed to be lower than the overall values for the species. Highly significant differences existed between specie; and represented alone about 55 per cent of the total estimated variation. Significant differences existed between trees but represented only 8 per cent of the total estimated variation E. microcorys aged 38 years at Butane, 26 years at Gisenyi and 26 years at Musha had average wood basic densities of 732, 618 and 719 kg/m3 respectively. Out of the three species considered, this species was found to have the densest wood. It was significantly denser than E. saligna but not significantly different from the 23-24 and 35 year old E. maidenii. E. maidenii aged 35 years at Butane, 9 years at Gisenyi and 23-24 years at Musha had average densities of 693, 583 and 693 kg/m3 respectively. The average basic densities of the 24, 9 and 23-24 year old E. saligna from Butane, Gisenyi andMusha were 589, 475 and 551 kg/m3 respectively. This species was found to be the least dense of the three. The average tree basic densities from stands in Rwanda are lower than the values for the same species growing in Australia. Compared to results from Brazil, averages for E. saligna from Rwanda are higher than those of the same species grown in Itupeva and in the same range as those grown in Mogi Guacu. In the axial direction, basic density increased significantly with height in the stems of E. microcorys. In E. maidenii and E. saligna, the increase was not significant at the 0.05 level. In the radial direction, basic density increased significantly from the pith outwards at height levels 1.3 m and at 33 per cent, but not at 66 per cent. It is suggested that E. maidenii, because of its dense wood and fast growth should be selected for large scale plantations for the production of fuel wood and construction wood urgently needed in Rwanda.
Description
Available in print form
Keywords
Eucalyptus, Rwanda, Wood density, Forests and forestry
Citation
Gashumba, E (1982) Basic density of the wood from Eucalyptus species grown in Rwanda, masters dissertation, University of Dar es Salaam. Available at (http://41.86.178.3/internetserver3.1.2/detail.aspx )