Taper functions to describe the stem profile and total bole volume for Pinus caribaea var. hondurensis in the Triangulo Mineiro

Abstract

The aim of this study was to evaluate the accuracy of taper functions for estimating diameters along the stem according to diameter classes and total volume. Studied was Pinus caribaea var. hondurensis in the Triangulo Mineiro region, state of Minas Gerais. The database consisted of 200 trees measured by the method of Hohenadl with ten sections, randomly chosen based on age and diameter distribution. The ages of the plantations ranged from 8 to 18 years. The twelve tested models had their performance assessed by the statistics: Schlaegel index; the standard error of estimate; deviation of diameters in each relative position along the bole; standard deviation of differences of diameters; sum of squares of relative residue and the percentage of the residual of diameters. Based on these statistics, ranking permitted to choose the best model to be used. The model from Hradetzky was the best for the total data set, being indicated for diameter estimates along the stem, the ratio di/dbh and the total volume of Pinus caribaea in the study region.