Propriedades físicas e mecânicas da madeira de Bertholletia excelsa bonpl. em função de tratamentos silviculturais, em um plantio na Amazônia central

Abstract

Some recent research suggests that liming, phosphorus fertilization and thinning may influence the growth and development of Bertholletia excelsa plantations. In this sense, we evaluated how these treatments influence the wood quality variables. The objective of this study is to analyze the relationship between the physical properties of wood and the variables moisture content, basic density and dimensional stability, as a function of the mechanical properties of resistance to static flexion and parallel compression of fibers, based on the responses to the effect of applied silvicultural treatments, besides classifying the best result to the improvement of technological properties, applied in a forest stand implanted in Central Amazon. The analysis of variance statistics was used to determine if there was a significant effect on the values of the properties tested in relation to the treatments. Liming has no significant effect on growth, but phosphorus and thinning increased by 47% and 82%, respectively, and the responses of trees to thinning were independent of liming and phosphorus addition. The treatments presented a significant effect among themselves, with the best response in relation to the technological properties, being the interaction between the silvicultural treatments of liming, thinning and phosphate fertilization, presenting an average density of 0.65 g/cm³, low dimensional volumetric variation, and with values of 104.77 MPa and 49 MPa for the modulus of static bending rupture and parallel compression of fibers, respectively, and 17,495 MPa and 5,173 MPa for the modulus of elasticity in the same tests. It should be noted that the thinning treatment also obtained satisfactory results, presenting values similar statistically to the liming + P + thinning treatment, being classified as the best treatment, if related to the economic and practical bias. Our results suggest the use of chestnut wood from plantations for commercial use in the timber industry, except in structural use.