Diametric increment modeling of Pinus taeda in function of the crown variables and competition index

Abstract

The objective was to generate a periodic annual basal area increment (IPAG) model for Pinus taeda valid for stands located in Rio Grande do Sul and Paraná. Temporary plots were installed in stands of Cambará do Sul and Ponta Grossa, where the tree larger diameter was considered dominant in the sample. All tree diameters at breast height and total height were measured. The dominant trees was also measured the crown diameter, crown insertion height and crown length to calculate h/d ratio, crown proportion, crown formal, coverage ratio and crown/trunk diameter ratio. An increment core was obtained from each dominant tree to calculate the IPAG the last five years. The model was built by stepwise method in the statistical package SAS® and validated by regression constraints. The variables initial diameter, crown diameter, degree of slenderness, and competition index based on the total and relative basal area were selected. The model showed high determination coefficient and low standard error of the estimate. The statistical analysis showed no difference between actual and estimated curves, showing the developed model may be used in both analyzed sites and similar sites.