Fabio Thaines

TAXA DE CORTE SUSTENTÁVEL PARA MANEJO DAS FLORESTAS TROPICAIS

There is a large gap in tropical forest management plans regarding to the intensity of logging and cutting rates. So far, it has been defined arbitrarily. This work aims at to define different cutting intensities for groups of tree species with different growth rhythm, in the state of Amazonas, Brazil. The study used the periodical annual increment, percentual in volume, of 26 species, obtained from permanent plots. The periodic increment percentage in volume for differentiating effect considered 1% difference as threshold. Three levels of logging intensity were identified for the commercial classes: 24.4% for group I, 35.4% for group II, and 42.4% for group III. The total sustainable cutting rate was 11.5m³ha -1 with cut intensity of 37%. The cutting rate calculation procedure is very simple and can be used by forest law and monitoring institutions.

Manejo da estrutura diamétrica remanescente de florestas tropicais

O incremento de uma floresta sob uma exploracao madeireira depende nao apenas do ritmo de crescimento das especies como tambem da distribuicao diametrica remanescente que devera permanecer pos corte. O trabalho avaliou, mediante simulacao, a estrutura diametrica remanescente de um talhao de floresta ombrofila no estado do Amazonas, visando a garantia de ter incremento que recupere a extracao. A simulacao do crescimento da floresta pos-exploracao, respeitando a taxa calculada e a estrutura, permitiram um incremento que pode recuperar o volume comercial inicial durante o ciclo considerado (25 anos). Observouse nas simulacoes que a remocao de todo volume comercial disponivel das especies estudadas impede a recuperacao da floresta no ciclo considerado. Observou-se tambem que as classes diametricas comerciais remanescentes (acima do centro de classe de 45 cm) sao responsaveis por 81 % do incremento necessario para recuperacao do volume comercial removido. Identificou-se um ponto otimo de classe diâmetro a ser mantida na floresta, acima do qual o retorno do volume comercial e nulo. O ponto crucial da recuperacao do volume extraido e o potencial de incremento da estrutura que deve permanecer no compartimento.

Management of Amburana cearensis var. acreana in Acre State, Brazil

This work has as its objectives: a) to assess the geographical distribution and population structure of Amburana cearensis var. acreana; b) to calculate sustainable cutting rates, according to stipulated cutting cycles, and c) to simulate the projected recovery potential in volume based on the calculated cutting rate. It was used data from sustainable forest management plans, and the results will contribute for future decisions about its endangered condition. The results did not corroborate the information that Amburana cearensis var. acreana is endangered in Acre state. However the management sustainability will only be feasible if considered the ideal remaining population structure and the estimative of the optimal cutting rate according to the cutting cycle.