Gerson Luiz Selle

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.

Dendrogramas de densidade para Hovenia dulcis Thunberg na região central do estado do Rio Grande do Sul, Brasil

The objective of this study was to elaborate dendrograms for the management of density, for populations of Hovenia dulcis located in the central region of Rio Grande do Sul, Brazil. To this end, we used information from 4 stands, aged 25 years, located at the Fundacao de Pesquisa Agropecuaria (FEPAGRO) and a population of free trees with diameters at breast height (DBH) ranging from 5 to 45 cm, located on the campus of the Universidade Federal de Santa Maria (UFSM), RS. In stands under competition, the data were collected from trees of the dominant, intermediate, and dominated stratas by the method of density point. In trees free of competition, the data were collected in the form of census. It was found that the model Reineke adjusted satisfactorily to estimate line density of canopy closure and anthropic, with slopes approaching -1.5, showing that the -3/2 self -thinning power law was contemplated and that the hypothesis postulated by Reineke was also satisfied. The population density for canopy capacity was 42.5% of the maximum number of trees, making it possible to construct diagrams for the management of density from 5 to 31 cm in diameter of average basal area of the tree.

Composição florística e estrutura fitossociológica de um "capão" de Podocarpus lambertii Klotz., no Rio Grande do Sul.

The present work studies the floristic composition and fitosociological structure of a natural “capao” of Podocarpus lambertii klotz. Located in Fazenda Vista Alegre in the Municipio of Sao Sepe, Rio Grande do Sul. In five samples of 10.00 x 50.0m (500 m²), were collected data of all trees with diametre higher ore qual to 10.0 cm at one metre height. Twenty nine species were found of which Podocarpus lambertii klotz. Is more important and characteristic. Also, were found Lithraea molleoides (Vell.) Engl., Casearia silvestris Sw. and Sebastiania klotzschiana Mull. Arg.