FLORISTICS RELATIONS AND PHYTOSOCIOLOGY OF A SECONDARY MONTANE ARAUCARIA FOREST FRAGMENT IN LAGES, SANTA CATARINA STATE

O presente estudo teve como objetivos caracterizar a estrutura fitossociol\uf3gica de um fragmento de floresta secund\ue1ria em Lages, SC, contextualizar a composi\ue7\ue3o flor\uedstica do componente arb\uf3reo do fragmento em rela\ue7\ue3o a outros remanescentes da regi\ue3o do Planalto Sul-Catarinense e avaliar a influ\ueancia de vari\ue1veis geogr\ue1ficas e clim\ue1ticas sobre os padr\uf5es observados. O levantamento da composi\ue7\ue3o flor\uedstica e estrutural da vegeta\ue7\ue3o arb\uf3rea, do fragmento estudado, foi conduzido em 25 parcelas de 400 m2, onde todos os indiv\uedduos arb\uf3reos com DAP (di\ue2metro medido \ue0 altura do peito) 65 5 cm foram medidos e identificados. Para o estudo das rela\ue7\uf5es flor\uedsticas entre o fragmento estudado e outros remanescentes da regi\ue3o foi utilizada a \uc1rvore de Regress\ue3o Multivariada, que utilizou matrizes flor\uedsticas de esp\ue9cies arb\uf3reas de presen\ue7a e aus\ueancia e de vari\ue1veis geogr\ue1ficas e clim\ue1ticas de cada remanescente. Foram encontradas 87 esp\ue9cies, distribu\ueddas em 36 fam\uedlias bot\ue2nicas. As esp\ue9cies de maior valor de import\ue2ncia no fragmento estudado foram Araucaria angustifolia (Bertol.) Kuntze e Podocarpus lambertii Klotzsch. A distribui\ue7\ue3o diam\ue9trica da comunidade demonstrou padr\ue3o pr\uf3ximo ao J invertido e as popula\ue7\uf5es tiveram padr\uf5es de distribui\ue7\ue3o diferenciados. Foram descriminados tr\ueas agrupamentos flor\uedsticos associados \ue0 sazonalidade t\ue9rmica e \ue0 temperatura m\ue9dia anual. O presente fragmento esteve agrupado a outras \ue1reas de sazonalidade t\ue9rmica maior ou igual a 3,053\ub0C.This study investigated the floristic composition and the tree community structure in a secondary Araucaria Forest fragment in the Southern Plateau Region of Santa Catarina state, Brazil, the floristic context of this fragment in relation to other areas of Araucaria Forest in the region and the influence of climatic and geographic variables on the clustering patterns observed. The phytosociological survey of tree vegetation was assessed through 25, 400 m2, plots, where all trees with DBH (diameter at breast height) 65 5 cm were measured and identified.The floristic relationship among remnants and the influence of climatic and geographic variables were analized through a Multivariate Regression Tree, using a presence-absence species matrix and a climatic-geographic variables matrix. In the study area, 87 species were found, distributed into 36 botanic families. The species with the highest importance value were Araucaria angustifolia (Bertol.) Kuntze and Podocarpus lambertii Klotzsch. While the distribution of individuals in diametric classes was similar to an inverted J shape for the community, the populations demonstrated different shapes of diametric distribution. In the region, three floristic clusters were discriminated, influenced mainly by temperature seasonality and annual mean temperature. The study site was grouped with together with other areas presenting temperature seasonality higher or equal to 3.053\ub0C