SORTIMENTO DO ESTOQUE VOLUMÉTRICO E RENDIMENTO DE MADEIRA SERRADA EM FLORESTA DE Pinus spp.

Abstract

The assortment of volumetric stock and efficiency saw lumber in Pinus spp. were studied in the municipality of Bituruna, in the southern region of the Paraná state, Brazil. Complete forest inventory (census) and a sampling forest inventory were taken (random and systematic sampling) with circular and rectangular plots with different sampling intensities (1, 2 and 5%). A completely randomized design was used to evaluate the assortment of standing forest using either complete or 100% (census) inventory and forest inventory by sampling, as well as testing different assortment alternatives. The data were submitted to the Bartlett test, analysis of variance (ANOVA) and the Tukey test to verify the differences between the means of the treatments. The relative losses of the forest harvest were studied, generating downgrade assortments coefficients. Sawmill efficiency were evaluated in a conventional sawmill and the optimization simulation was performed with MaxiTora software. The results showed that the assortment used, directly influences the commercial volume, ranging from -21.51 to 1.94%. The losses related to the forest harvest were 11.92%. The assortments downgrade resulted in losses of 5.41% in gross revenue of the forest stand, which are caused by tree stems nonsymmetry (bifurcations and tortuosities), by pest damage and lack of precision of the processor head. The efficiency of non-scheduled logs sawing lumber varies form 35.79 to 45.09%, however the efficiency of a sawing lumber, considering the use of a timber optimization software, ranges from 36.81 to 55.15%. The greatest economic benefit of sawed lumber was observed in logs with diameters ranging from 16 to 23.