Dinâmica da distribuição diamétrica de três espécies arbóreas em uma área manejada na flona do Tapajós.

Abstract

Knowledge of the composition of tree species and the distribution of their individuals is essential to efficiently plan the management and conservation of native Amazonian flora. The analysis of the distribution of individuals in diameter classes is a tool that can be used to infer about the past and future of plant communities. In this work we used data from a continuous forest inventory, collected for 31 years in permanent plots, and data from two forest inventories at 100% intensity, in order to analyze the diameter distributions of the species Hymenaea courbaril L., Goupia glabra Aubl. and Caryocar glabrum (Aubl.) Pers., after logging and applying silvicultural treatments. Diameter classes with an interval of 10 cm between them were established to analyze the diameter distributions of the numbers of trees of these three species. Weibull's probability density function of three parameters (3P) was used to project the diameter distribution, as it is one of the distribution models most used in forestry studies. Data adherence to the Weibull 3P distribution was assessed using the Kolmogorov-Smirnov (KS) test. The Kruskal-Wallis test was also used to find the difference in DBH between the years studied. As a result, there was adherence of the values estimated by the Weibull 3P functions for the three analyzed species, that is, the expected and observed frequencies were statistically similar. It was found that the three species studied can be used in a polycyclic management system, as they have sufficient numbers of trees for continuous timber production. The H. courbaril population has a decreasing diameter distribution of the number of trees in the forest before logging and during the entire period (32 years) evaluated after logging, which can guarantee its continuous production. The C. glabrum population also had a decreasing diameter distribution, although with a reduced number of individuals, but sufficient to maintain continuous production. G. glabra did not present a decreasing diameter distribution, however, after logging, the individuals were constant throughout the evaluated period, including a high abundance of young trees at the end of the cycle, 32 years after logging, guaranteeing their permanence in the area with continuous production.