Qualidade da madeira de galhos residuais pós-colheita de Hymenaea courbaril L.

Abstract

Branches remain at the forest as residue after logging activity. Since the large Amazonian trees have branches with considerable diameter suitable for industrial processing, it may be an alternative sustainable wood source that could be proper for several uses. Due to the reaction wood formation in branches, macro and ultrastructural important variations may occur in its characteristics in relation to the trunk. For appropriate knowledge and suitable use with added value, it is important to study the variability of such characteristics and their effects on the wood properties. This study aimed to investigate the branch wood quality of Hymenaea courbaril L., comparing to trunk wood. In each of the two sampled trees, one disc was removed from the branch (diameter>30cm) located at 1 m from its base and from its respective trunk one disc was cut at 1.3 m height above the ground. For fibers biometry, microfibril angle, physical and mechanical properties studies, in each disc samples were cut in eight radial positions, four in the tension and opposite wood each. For chemical analyses it was obtained six radial samples, three from each wood type. The analyses were accomplished according to standard procedures, and microfibril angle was realized by polarized light microscopy. The results were analyzed with descriptive statistic, as well as Pearson correlation and multiple regression models adjusted to estimate compressive strength, anisotropy coefficient and basic density. In general wood properties were different comparing branch and trunk wood. However, almost all tension and opposite wood properties were similar, which indicates appropriate processing and use with no need to separate both wood types. By using stepwise regression analysis, it was possible to estimate the compressive strength parallel to the fibers, density and anisotropy coefficient as a function of fiber biometry, physical and chemical wood properties. The adjusted coefficients of determination indicated that variations in strength, density and anisotropy coefficient are explained by 97%, 78% and 70%, respectively, by the variations in the wood characteristics that were significant for each adjusted model. It is recommended the branch wood utilization for furniture, production of artefacts, decorative items and tools in general. Other uses as flooring may be viable, since additional tests that evaluate this possibility be carried out.