This work describes species composition and structure of the tree component of an area of lower to upper montane seasonal semideciduous forest located at Serra de São José, Tiradentes, SE Brazil. Floristic and structural comparisons are made with 23 other forest areas of the region using canonical correspondence analysis differentiating environmental and spatial variables. The floristic analyses indicated that, despite the transitional character between lower and upper montane forests, the tree flora of Serra de São José showed stronger link than the former. Floristic and structural variation among the 24 forests was significantly related to altitude, duration of the dry season and soil saturation of bases. Furthermore, a significant correlation was also found with spatial proximity of the areas.