Análise de danos de colheita de madeira em floresta tropical úmida sob regime de manejo florestal sustentado na Amaz?nia ocidental

摘要

The objective of this work was to identify, qualify and quantify the intensity of damage from natural causes and forest harvest in a non-exploited old growth forest (FPNE) and in a harvested old growth forest (FPE). The studied area is located in the counties of Manicoré, Amazon, Brazil, with an area of 204 ha of FPNE and 202 ha of FPE, respectively. The inventory was carried out applying the randomized sampling method, in both areas. Sampling collection was carried out in two levels of approach. In level I, five plots of 100 x 100 m (1 ha) were established, and the individuals with DBH 3 15 cm were evaluated. In level II, the plots of level I were systematically subdivided in subplots of 10 x 10 m (100 m2), being randomly sampled only five of these per plot of level I, with an area of 2,500 m2, where all the individuals between 5.0 ￡ DBH < 15 cm (large samplings) were evaluated. The assessment of damage caused to the remaining trees indicate that only 10% of the adult vegetation presented damages in the non-exploited forest. In the exploited forest, the damage caused by harvest operations, such as felling log extraction, skidding trails and clearcut, was of 29%. The changes in the structures of volume, basal area and diameter were more evident in the greater diameter classes, where reductions of 30%, 29% and 27%, occurred respectively. Nevertheless, this reduction can be considered normal, since the sampling was collected immediately after forest harvest operations.