Efeitos do solo, adubação e tipo de fuste nos parâmetros de produção e qualidade da madeira de Tachigali vulgaris visando fins energéticos

Abstract

Current discussions on climate change require research that scales up the use of sustainable energy sources. Tachigali vulgaris is a South American species whose wood has been widely studied for energy purposes. Although previous studies have shown that T. vulgaris wood has promising characteristics, silvicultural aspects, such as fertilization and its effects on wood quality and species growth, are unknown. In addition, it is essential to understand the effect of bifurcations, commonly found in the species, on the characteristics of its wood. The aim of this study is to evaluate the effects of soil, fertilization, and bifurcation on the yield and quality of Tachigali vulgaris wood. The research was carried out in 2 experimental plantations of T. vulgaris located in the mesoregion of the lower Amazon, state of Pará, Brazil. The plantations have different soil textures: Yellow Latosol sandy loam texture and Yellow Latosol clay texture. The experiment was installed in 2010 and has a spacing of 3x2 m between trees. 4 blocks per area and 3 fertilization tests were considered: the control, in which there was no fertilization with phosphorus and potassium; treatment 2, in which only phosphorus was fertilized; and treatment 3, in which phosphorus and potassium were fertilized. In each test, a tree with a single stem and a bifurcated tree were sampled. The dissertation was divided into 2 chapters: the first discusses the effect of the treatments on the characteristics of the wood and charcoal produced from the species, and the second discusses the effect of the inorganic composition present in the wood on the quality of the wood for thermal energy generation. Analyses of the basic density of the wood, ash content, calorific value, extractive content, lignin content and inorganic components present in the wood were analyzed. Charcoal was also produced from the wood of the species. For this charcoal, yields, bulk density, immediate chemical composition and superior calorific value were evaluated. The results do not show effects of the evaluated treatments on the basal density. Woods with a diameter at breast height (DBH) less than 15 cm had a density below 0.500 g/cm3. There was an effect of the evaluated parameters on ash (0.35%, dry basis - db), total extractives (4.65% (db) and total lignin (31.34%, efdb). Growth parameters have a great effect on energy productivity (2.65 GJ/tree) and should be considered in the evaluation of the potential of the species for energy plantation composition. The inorganic composition present in the wood affected the growth characteristics and quality of the wood, in addition to presenting important implications in the use of the wood of the species for energy, mainly due to the absence of K2O and the high values of F2O3 (9.32%) and Al2O3 (39.73%) estimated for the ashes. The study shows that the characteristics of the species' wood are suitable for energy use. However, the large variation in volume should not be ignored, as it affects the energy productivity of wood and charcoal.