Longitudinal variation of wood quality in the five forest species from Caatinga

The present study aimed to evaluate the dendrometric and chemical characteristics and variation of basic density and moisture content (green) of the wood of five Caatinga forest species along the commercial longitudinal direction (base-top) of logs. The studied species were pau-branco (Auxemma oncocalyx (Fr. All.) Taub.), jurema preta (Mimosa tenuiflora (Willd.) Poir.), jurema-de-embira (Mimosa ophthalmocentra Mart. ex Benth.), pereiro (Aspidosperma pyrifolium Mart.) and sabiá (Mimosa caesalpiniifolia Benth.). Fifteen trees were harvested, three of each species. The trees had diameter at breast height of 8 to 12 cm. Five disks with thickness of 10 cm were removed from each tree at the positions 0 (base), 25, 50, 75 and 100% of the commercial height. The dendrometric characteristics showed that the choices of the trees contributed to a better analysis of the physicochemical properties of the wood. The five studied species could be described by the same model of longitudinal variation of basic density, decreasing from the base to top, while the moisture content (green) presented inverse behavior, with an increase in this same direction. All species had good quality for the production of sawn lumber, veneers, firewood and charcoal. In the chemical composition, the wood presented constituents that convey natural durability, as well as use for energy purposes.