Dinâmica e produção de uma floresta sob regime de manejo sustentável na Amazônia Central

Abstract

Nowadays sustainable forest management is considered one of the best options for using the natural resources without environmental degradation. However, there is still a need for greater understanding of the effects of impacts and future production capacity of the forest. Thus, the aim of this study was to evaluate the short and medium term effects of polycyclic silvicultural system, dynamics and production, in a dense rain forest in the state of Amazonas, based on three Annual Production Units (APU) of forest management the company Mil Madeiras Preciosas in Itacoatiara/AM, explored between the years 1996 to 1998. The continuous forest inventories were performed before and after logging in 1996, 1997, 1998, 2001 and 2014 in 41 permanent plots of 1 hectare installed in the APU B, C and D, which were measured all trees with DBH less than 15 cm. Admission rates and mortality were calculated, DBH, basal area, volume, and their periodic annual increments (PAIs), and the variation of the number of trees and species. It was noted that the forest did not change significantly in number of species after the operation, on the other hand, a significant increase in the total number of species in the last reporting period, occurring equivalently in three compartments. On average values, before the exploration, 297.65 trees.ha-1 were recorded, equivalent to basal area of 26.42 m².ha-1 and the volume of 393.62 m³.ha-1. In 2014, 16-18 years after the operation, all APUs showed a significant increase in the three variables (number of trees, basal area and volume), surpassing in number of trees, the values found before the operation, considering all species. In the last period of analysis, the population had an average rate of inflow of 3.20%. year-1, and 1.47% .year-1 for mortality. Considering only the species of commercial value, the rates were 2.50%. year-1 and 1.30% year-1 for admission and mortality, respectively. On average values, the volume growth rate was 4.63 m3.ha-1.year-1, of which 1.69 m3.ha-1.year-1 commercial species. Analyzing the forest by diameter class, it was observed that this increase tends to increase as you increase the diameter class, reaching its peak in the trees of 75 and 85 cm, with the highest rates recorded soon after the operation. It was also observed that the growth of the forest, 16-18 years after the operation, provided the regeneration of most clearings observed soon after the operation, they, passing to the stage of forest under construction or even mature. The forest studied had stock in basal area and volume of the total population and commercial species (16 to 18 years after logging), equivalent to those recorded in the first measurement, indicating that the applied felling intensity is favoring the recovery of the stock timber into a second cycle. However, due to the different measuring ranges, it was not possible to conduct a transition matrix that includes all APUs. This fact limited the analysis and consequently prevented reliable projections in the long term