Relações morfométricas e potencial de manejo de Maclura tinctoria (L.) D. Don Ex. Steud em formações secundárias no noroeste do Rio Grande do Sul

Abstract

The objective of this study was to characterize Maclura tinctoria individuals in anthropic secondary formations, as their growth aspects in diameter and basal area, their morphometric relationships, spatial distribution and crown regularity. Also analyzing the behavior of individuals with more than one trunk, called multitrunks, and establish regression models to estimate basal area increment, crown diameter and height. For this, they were measured in two distinct areas in Porto Mauá, RS, diameter at breast height, total height, crown diameter and punctual density of each individual (using Bitterlich method). The morphometric indices were calculated based on data obtained from the field. The regularity of the crown was obtained by the coefficient of variation of the crown rays. For spatial analysis was calculated K Ripley function. The annual periodic increment in diameter (IPAd) and basal area (IPAg) were obtained by analysis of growth rings. In order to verify if these variables influence increments, Pearson correlation analysis was performed. It was developed mathematical equations, the stepwise method to estimate the increment in basal area, crown diameter and total height. The tendency of multitrunks individuals in relation to the single-stem for all variables was verified using analysis of covariance. The multitrunks trees in general show a similar tendency to the trees with a single stem. The studied species have moderate growth to fast, presenting therefore great potential for management. The spatial distribution indicated groupings to a higher range to 15 meters. Morphometric indices varied widely, demonstrating the plasticity of the species. As the variation in crown rays was extensive, featuring its irregularity. The morphometric variables, did not exert significant influence on the increment in diameter of Maclura tinctoria individuals. This indicates that the growth in diameter is statistically the same regardless of tree form. However, the degree of slenderness and comprehensiveness index correlated with the periodic increment in basal area. It was possible to define equations with good settings for height, crown diameter and increment in basal area of the species. All the elaborate equations had dbh as dependent variable, indicating the strong correlation of this variable with the other characteristics of trees Maclura tinctoria.