ABSTRACT
The native vegetation from Brazilian Northeast has been explored and used intensively and inadequately as a source of energy and material for rural constructions. Now, it is recognized how important it is to get to know the characteristic of the wood produced by this vegetation. Thus, this study aims to provide information on the physicochemical and energetic characteristics of wood, carbonization yields and characterization of the charcoal from wood of Poincianella pyramidalis Tul. L.P.Queiroz and Handroanthus impertiginosus (Mart. ex DC.) Mattos. To meet the goal five trees from each species were cut down and randomly sampled at Santa Barbara Farm, located in the municipality of São Mamede-PB. The trees were properly identified and transported to the Department of Forest Products Technology (STPF) at the Federal University of Campina Grande. Thirty centimeters sections were removed from each tree at 0 (base), 25, 50, 75 and 100 % of the commercial height (trunk diameter > 5 cm). A 2.5 cm thick disc was removed from the median part of each 30 cm section, and each disc was subdivided in four wedge pieces, passing through the trunk pith. Two opposite wedge pieces were used to determine the basic density of wood, ant the other two pieces were put aside in order to carry out physical, chemical and energetic analyses, carbonization yields and characterization of the charcoal produced by the studied species. Basic density was determined according to the method of hydrostatic balance and to determine the average basic density of each tree, the volume between sections of each disc was used as a weighting factor. After the air drying, the samples intended for chemical analysis were transformed into sawdust and quantitative determinations of total extractives were performed, lignin, ashes, and the holocellulose content was estimated by difference. The samples intended for carbonization were processed into chips, and carbonized in an electric oven (furnace) for 5h30mim. Determinations of the yield of products of carbonization were carried out as well as physical and chemical properties of wood charcoal. In general, the studied wood showed similar physical characteristics. Regarding to chemical properties, Pau-d'arco wood showed a higher lignin content (28.40 %), and there were not any significant differences among species for the holocellulose content The superior calorific power of Catingueira wood (4413.50 kcal.kg-1) showed the lowest values for wood (4413.50 kcal.kg-1) and charcoal (6247.80 kcal.kg-1) respectively. The catingueira wood showed a higher charcoal yield (43.03 %), but lower quality. The Pau-d'arco charcoal had the highest fixed carbon content (67.68 %). These species showed similar charcoal true density and fixed carbon production. It is concluded that the two species which occurs in the Northeastern semiarid, have good properties for charcoal production. The Pau-d'arco showed the best properties for energy use.
Keywords:
Caatinga; wood; charcoal