Physical and chemical properties of wood from Eucalyptus and Corymbia clones in different planting densities

The present work aimed to evaluate some technological characteristics of the wood of two commercial hybrid clones of Eucalyptus spp and two hybrid clones of Corymbia spp, implanted in three different planting spacings, at 24 months of age. Four trees per clone were sampled at each spacing to determine the following wood characteristics: basic density, gross calorific value, energy density and cellulose, hemicellulose, lignin, ash and carbon contents. There was a significant effect of the clone x spacing interaction for the basic density, energy density, lignin and cellulose contents of the wood. Eucalyptus showed the highest levels of lignin and cellulose, and hybrid clones of Corymbia the highest values of basic density and energy density of wood, with emphasis on clone C3, where the highest averages of the study were verified. For the levels of hemicelluloses and ash in the wood, the clone effect and spacing effect were observed. As for the carbon content and the gross calorific value in the wood, there was no significant effect, either from the clone, the spacing or the interaction of these two factors. The results show that there is variability in the characteristics between the genetic materials evaluated and in relation to the planting spacing tested. It should be noted that the choice of the best genetic material should be based on the technological characteristics of the wood, but also the forest productivity associated with good silviculture of the species should be evaluated.