Preliminary Biomass Studies in Young Eucalypts

Abstract

The wet and oven-dry biomass of various above-ground components of four to five-year-old Eucalyptus deanei, E. globulus ssp. globulus, E. nitens, E smithii and E. viminalis were determined from small samples on the Transvaal Highveld. Close relationships were established between the oven-dry mass of twigs and branches, leaves, stem wood and stem bark respectively and the square of breast height diameter. Tree height was not significant as an additional predictor variable because of the close relationship between height and diameter, the trees being the same age and growing on the same site. Total above-ground biomass and the relative proportions of the various components for various diameter classes is given for each of the above species. There are considerable differences in these proportions between the species. However, the results of this study indicate that the total biomass production for young eucalypts can be increased by 40 to 55 % by making use of above-ground components other than stem wood. The inverse relationship between specific gravity and moisture content of the stem wood was clearly illustrated.