Artificial form factor equations for Tectona grandis in different spacings

摘要

The use of form factors is a practical alternative for estimating tree volume. However, only a few studies in this topic are relevant to Tectona grandis, and only few to those that evaluate the effect of spacing on it. The goal of this study was to generate form factor equations and evaluate spacing influence on it in teak plantations. Samples were taking in 3 × 2 m, 4 × 3 m, 5 × 2 m, and 6 × 2 m plots. The database consisted of rigorous cubage of 120 trees, 30 of which were utilised in spacing for the calculation of the artificial form factor models; these were compared using statistical indicators and graphic analyses. In order to assess possible differences among the equations, the identity test of models at the p < 0.05 significance level was utilised. The results of the identity test of models show that it is possible to utilise a single equation (the reduced model) to estimate the form factor for all spacings, indicating that the factor was not influenced by plantation spacing. It was found that with increasing diameter, teak tree trunks became more cylindrical. Stabilisation occurs starting at a diameter of 27 cm and a height of 25 m, with a form factor of 0.47.