Effects of silvicultural treatments on the dynamics of diametric distribution in an area of the Amazon rainforest using the Weibull function

This study analyzed the diametric distributions before and after forest management in a rainforest area of the Amazon in the Amapá State, Brazil. It aimed to understand how the diametric distribution of the forest was recovered after 27 years of forest management between 1984 and 2011. For this purpose, data from 40 permanent plots were used. The Weibull function for the diametric distribution was fitted to data from 1984, 1990, and 2011 by applying the Table Curve statistical package over the control treatments T0 (0% exploration and 0% thinning), T07 (25% exploration and 50% thinning), and T11 (35% exploration and 50% thinning). Comparisons between the diametric distributions before and after the forest management were conducted using the χ2 test. After fitting the Weibull function, the results showed good adherence by the Kolmogorov–Smirnov test (p > 0.05) for all treatments and periods. There were no differences in the diametric distributions before and after management for T0. In contrast, diametric distributions were different before and after forest management regarding the intervention levels for T7 and T11. Therefore, for T11, the diametric distribution recovered after management, indicating that forest management during 1984-2011 was enough to recover the diametric distribution to its initial state.