Revista Árvore (Aug 2005)
Emprego do método BDq de seleção após a exploração florestal em Floresta Ombrófila Densa de Terra Firme, Amazônia oriental The BDq selection method after logging in a terra firme dense rain forest, eastern Amazonia
Abstract
Este estudo teve como objetivos analisar a estrutura diamétrica pós-colheita seletiva da Floresta Ombrófila Densa de Terra Firme, aplicar o método BDq nas atividades de tratamento silvicultural e manejar a floresta, visando a uma estrutura balanceada dos diâmetros. A pesquisa foi realizada na Unidade de Manejo Florestal (UMF) da Fazenda Tracajás (02º35'53"S e 47º47'10"W), empresa Nova Era Agroflorestal, município de Paragominas, Estado do Pará, Brasil. A floresta foi estratificada em áreas homogêneas, denominadas classes I, II e III de estoques volumétricos, empregando-se as técnicas de análises de agrupamento e discriminante. Em cada classe de estoque foram instaladas, aleatoriamente, cinco parcelas de 100 x 100 m (1,0 ha), para medição dos indivíduos com dap > 15 cm. No centro de cada parcela de 100 x 100 m, foi instalada uma subparcela de 10 x 100 m (0,1 ha), para medição dos indivíduos com 5 cm The objectives of this study were to analyze the diameter structure of a terra firme dense rain forest after selective logging, to apply the BDq method in the silvicultural treatment activities and to manage the forest aiming at a balanced diameter structure. The research was carried out at the Forest Management Unit (FMU) in Tracajás Farm (02º35'53" S and 47º47'10"W), owned by Nova Era Agroflorestal, in Paragominas, Pará, Brazil. The forest was stratified into homogeneous areas, called classes of volume stock I, II, and III. In each of the stock classes, five plots of 100 x 100 m (1 ha) were randomly set up for measurement of the individuals with dbh > 15cm. In the center of each 100 x 100 m plot, a subplot of 10 x 100 m (0,1 ha) was established for measurement of the individuals with 5cm < dbh < 15 cm. The BDq selection method was used taking into account the remaining basal area (B), maximum diameter (D) and the De Liocourt constant (q). In the stock class I, the proposed management method allowed the removal of 56.4 trees/ha, 3.33 m²/ha and 67.64 m³/ha, with a 13.1% reduction of the basal area. In the stock class II, 53.7 trees/ha, 3.88 m²/ha and 65.96 m³/ha were removed, with a 16.2 % reduction of the basal area. In the stock class III, 63.3 trees/ha, 3.13 m²/ha and 46.76 m³/ha were removed, with a 14.0% reduction of the basal area. Few trees or a deficit was observed in the higher diameter classes due to the selective logging. The periodical removal of trees should occur in the lower diameter classes, aiming at a balanced diameter distribution and the conduction of the forest to a balanced structure during the cutting cycle, leading to a continuous use of the forest woody products.
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