Non-segmented and segmented taper models to Tectona grandis in center-southern region of Mato Grosso

Abstract

The aim of this study was to compare the accuracy of the non-segmented polynomial models of Fifth degree and Hradetzky from 1976 and the segmented models of Max and Burkhart from 1976 and Clark et al. from 1991, in estimating diameters along the stem of Tectona grandis L.f., with adjustments for the full set of data and by diameter class in a 16 years old stand in the center-southern region of Mato Grosso State, Brazil. The database consisted of 114 trees, scaled by the modified Hohenadl method and distributed in diameter classes. The models adjustments were evaluated according to the adjusted coefficient of determination, standard eError of estimate and distribution of residuals. The accuracy of the models along the stem was evaluated by deviation, standard deviations of differences, sum of squares of relative residuals and percentage of residuals. The Hradetzky equation was the most accurate to estimate diameters along the stem of Tectona grandis, both for the total data set and for diameter classes, except Class 3, where Clark et al. model was more accurate.