Modelagem volumétrica para Bertholletia excelsa Bonpl. em povoamentos experimentais no Oeste do Pará

Abstract

This work aimed to adjust volume equations for the species (Bertholletia excelsa Bonpl.) (Castanheira) in two experimental stands in western Pará, in the municipalities of Belterra and Prainha. The studied plantations were installed in the 70's, being the Belterra area with 45 years, planted in 4 x 4 m spacing and Prainha, with 40 years, in 5 x 5 m spacing. Forty-five trees with the best representativeness were selected regarding the variation of the diameters and visual quality of the stems (free of bifurcations, defects or degradations), being 20 trees in the Belterra area and 25 in Prainha. The trees were cubed at height (m) 0.1, 0.3, 0.7, 1.3, 2.0 and every two meters to commercial height, non-destructively using the Criterion® RD1000 dendrometer. From these data, 4 double and single entry volumetric models were used, analyzing the parameters obtained for each adjustment, where we observed the highest values of R²aj and the lowest values of Sxy and CV%, comparing the actual volume with the estimated and graphical analysis of the two. waste. Regression analysis showed efficient estimates of the species for the two areas under study, highlighting the Spurr models for Belterra and Schumacher-Hal experimental planting for Prainha experimental planting, presenting precise patterns with significant R²aj values (0.96; 0.97), low CV% (11.29; 21.21), acceptable Syx (0.18; 0.27) and randomly distributed residues around the axis, ranging from 25.54 ≥ ≤ -22.07 and 27.59 ≥ ≤-26.27. Therefore, it is concluded with this study that the use of the Schumacher-Hall and Spurr mathematical models can be recommended for estimating the volume of the species (Bertholletia excelsa Bonpl.) In planted forests in the western region of Pará because it presents significant regression parameters.