Resumo. In order to identify the floristic and structure patterns of the tree component and to determine the environmental variables that influence these patterns in a sector of montane Araucaria Forest remnant, 50 plots of 10 × 20 m were allocated, using systematic sampling, 30m apart from each other, in Campos Novos, SC. Within the plots, all living trees with cbh (circumference at breast height) ≥ 15,7 cm were identified and measured (cbh and total height). Environmental data related to chemical and physical properties of soils and topography were also collected from each sampled plot. To describe the tree vegetation richness, diversity and structure, the Shannon-Wiener index (H’), the Pielou evenness index (J’) and the phytosociological estimates were obtained. The floristic and structural organization of the fragment was analyzed through a NMDS (Nonmetric Multidimensional Scaling). The environmental variables were fitted a posteriori in the produced ordination, being those significant (p < 0.05) plotted as vectors. A total 1.027 individuals were sampled, which represented a basal area of 43.57 m 2 , distributed in 88 species and 41 families. The diversity of the fragment studied was relatively high (H’=3.59) with low dominance (J’=0.80). The specie with higher VI was Araucaria angustifolia (Bertol.) Kuntze (14.44%). The NMDS indicated a floristic-structural gradient related to the mean elevation (altitude), soil base saturation, soil pH and P soil content.