DENSITY AND PROPORTION OF SAPWOOD AND HEARTWOOD IN NEW Eucalyptus spp CLONES

The generation of new genetic materials to meet the diverse demands of the wood market requires a continual evaluation of their technological properties. In the present study, heartwood and sapwood relative content at three stem heights (0,10 m, 2,80 m and 5,50 m) as well also the variation of density in the axial and radial direction of pure Eucalyptus grandis (rose gum) and hybrid (Eucalyptus grandis (rose gum) x Eucalyptus camaldulensis (red gum) and Eucalyptus grandis (rose gum) x Eucalyptus tereticornis (red irongum)) clones of 11-years-old were evaluated. Pure clones showed 10 % more heartwood than the hybrids. The hybrid material reached the highest average value of densities, being more homogeneous in the radial and axial profile. In general, the density presented an increasing pattern in the radial direction. No significant differences were found in the density for the heights studied in the hybrid clones, while the pure clones showed significantly higher density values at 0,10 m. Sapwood density was greater than heartwood density for all three stem heights in all genetic materials. As a result, the hybrid clones could be suitable for the production of cellulose pulp due to the lower proportion of heartwood, which facilitates the bleaching process, as well as for their use as sawn wood or structural plywood due to their high density and homogeneity in height.