Ecological factors that determine the occurrence of Araucaria angustifolia and Podocarpus lambertii in Mixed Ombrophylous Forest at Sao Francisco de Paula's FLONA, RS, Brazil/Fatores ecologicos determinantes na ocorrencia de Araucaria angustifolia e Podocarpus lambertii, na Floresta Ombrofila Mista da FLONA de Sao Francisco de Paula, RS, Brasil

• Published in: Ciência rural Vol. 40; no. 1
• Main Authors: Longhi, Solon Jonas, Brena, Doadi Antonio, Ribeiro, Sylviane Becker, Gracioli, Cibele Rosa, Longhi, Regis Villanova, Mastella, Tarso
• Format: Journal Article
• Language: Spanish
• Published: Universidade Federal de Santa Maria 01-01-2010
• Subjects: Analysis; Forest reserves
• ISSN: 0103-8478

The present research was accomplished at Sao Francisco de Paula's National Forest (FLONA), in Rio Grande do Sul. The objective was to determine, through logistics regression analysis, the environmental and competition factors that could influence on the occurrence of Araucaria angustifolia (Bertol.) Kuntze and Podocarpus lambertii former Klotzsch Endl. species in Mixed ombrophylous forest. For the study, the individuals with cap=30cm had been evaluated, in 1000 samples of 10 x 10m, demarcated in ten permanent conglomerate of 1ha (100 x 100m) previously installed in the forest. In each sample the factors that might influence the occurrence of the species and the factors related the habitat was assessed as physical of the soil (depth, rocky outcrop and humidity), exhibition to the light and the relief inclination. The competition factors were: basal area, sub-forest density and individuals' frequency. For the obtained results it had been possible to conclude that the Araucaria angustifolia prefers places with deep soils, north exposition and low individuals frequency. On the other hand, Podocarpus lambertii prefers no stony places, little sloping, with south exposition, relatively humid, with high frequency of individuals and high sub-forest density Key words: logistics regression, multivariate analysis, araucaria's forest. O presente trabalho foi realizado na Floresta Nacional (FLONA) de Sao Francisco de Paula, no Rio Grande do Sul. Teve como objetivo determinar, via analise de regressao logistica, os fatores ambientais que influenciam a ocorrencia das especies Araucaria angustifolia (Bertol.) Kuntze e Podocarpus lambertii Klotzsch ex Endl. em uma area de Floresta Ombrofila Mista na FLONA de Sao Francisco de Paula. Para o estudo, foram avaliados os individuos com cap=30cm, em 1.000 subunidades amostrais de 10 x 10m, demarcadas em 10 conglomerados permanentes de 1ha (100 x 100m) previamente instalados na floresta. Em cada subunidade amostral, foram avaliados os fatores passiveis de influenciar a ocorrencia das especies, como os fatores relativos ao habitat: fisicos do solo (profundidade, presenca de afloramentos rochosos e umidade), exposicao a luz e inclinacao do terreno; e os fatores relativos a concorrencia: area basal, densidade do sub-bosque e frequencia de individuos. Pelos resultados obtidos, foi possivel concluir que a Araucaria angustifolia ocorre em locais com solos profundos, expostos para o norte e com baixa frequencia de individuos. Por outro lado, Podocarpus lambertii prefere locais nao pedregosos, pouco inclinados, com exposicao sul, relativamente umidos, com alta frequencia de individuos e alta densidade do subbosque. Palavras-chave: regressao logistica, analise multivariada, floresta com araucaria.