Estrutura e padrões de distribuição espacial de espécies arbóreas em uma amostra de Floresta Ombrófila Mista em Nova Prata, RS

Abstract

The objective of this study is to describe the vegetation structure and the spatial distribution patterns of tree and shrub species in one hectare of a Mixed Ombrophylous Forest, localized in the County of Nova Prata, state of Rio Grande do Sul, Brazil. Using the fixed area method, were installed 20 samples of 10 x 50 m (500 m2), completing one sample of the 100 x 100 m (10000 m2) and measured all individuals with diameter at breast height (DBH) ³ 9,6 cm (30 cm of circumference), that make up the canopy of the forest. The sample of vegetation studied showed a medium diversity of arboreal and shrub species (55 species with DBH ³ 9,6 cm) and a large density of individuals per ha (848 individuals/ha), similar to the ones found in secondary forests, in the domain of the Mixed Ombrophylous Forest. The vegetation in the sample presented a larger proportion of species aggregated or with aggregation tendency (46,7 %), revealing that the larger tree population make up small spots or groups in the vegetation, with larger values obtained for the Variance/Average rate. This study, even though treating of a small spatial scale analyze (10000 m2), depict the density and the distribution of the arboreal and shrubs species in a part of secondary forest, that was damaged by commercial exploitation important fragment of the present forests of the state of Rio Grande do Sul, Brazil.