ABSTRACT
The aim of this paper was to know and analyze the floristic composition and describe the structure of the arboreous component of a fragment of Montane Mixed Ombrophylous Forest in Criúva - State of Rio Grande do Sul, Brazil. Were inventoried 673 individuous with DBH ≥ 5 cm eight 10 x 100 m plots, distributed into 37 species, 32 genera and 22 families. The Shannon diversity index was 2,768. The families which presented the largest number of individuous were: Araucariaceae, Myrsinaceae, Euphorbiaceae, Anacardiaceae and Rutaceae. The forest canopy is dominated by Araucaria angustifolia and the understory, by species of the families Lauraceae and Myrtaceae. The total density found was 841,25 individuous/ha, the mean DBH was 24,01 cm and the highest VI values, in descending order, were: Araucaria angustifolia, Sebastiania commersoniana , Lithraea brasiliensis, Zanthoxylum rhoifolium and Myrcia sp.. The fragment presents a considerable floristic diversity of species, in spite of the suffered disturbances in the past. For the vegetation to reach the floristic and structural characteristics close to the one of the original vegetation it is necessary to avoid the presence of bovine and equine in the area and explorations of the forest.
Key words:
fragment forest; Araucarian forest; Mixed Ombrophylous Forest