Qualidade da madeira serrada e demarcação do lenho juvenil e adulto do mogno africano

Abstract

The aim of this work was determine the transition from juvenile and mature wood and evaluate the wood quality for the lumber production of two species of African mahogany (Khaya ivorensis and Khaya senegalensis). The material researched (19 years old) was from experimental plantation of Vale Natural Reserve, Linhares, ES, Brazil. Were measured at commercial height, diameter at breast height - DBH and the longitudinal residual strain (method CIRAD- FORÊT). After cut the trees, discs at the height of DBH and logs were removed along the stem, being the top bottom of the logs photographed. The morphology of fibers and vessels was analyzed by microscopic study of wood; the microfibril angle measured using by polarized light microscopy; apparent density, determined by the technique of X-ray densitometry; and basic density and volumetric shrinkage, determined in accordance with current technical standards. The end splits of the logs were measured using an images analyzer software and defects of dried boards also were examined. Through the radial variation of fiber length and frequency of vessels was possible to demarcate the point of transition between the juvenile and mature woods for the two species of African mahogany. The juvenile wood corresponded the highest portion of diameter of the stem (height DBH) and its properties were more variable and inferior than the mature wood, for both species of African mahogany. There were not differences of longitudinal residual strain, index end splits of logs and boards and displacement of the pith between species. However, were observed in the logs and boards of the species K. ivorensis the larger splits, while the highest index warping was observed in the boards of the species K. senegalensis.