The Atlantic Forest covered most of the Northern region of Rio de Janeiro state, being reduced, nowadays, to less than 10% of its original area. However, little is known about the floristic composition and structure of the forest fragments of this region. This study aimed to characterize the floristic composition and structure of a Dense Ombrophilous Submontane Forest at Parque Natural Municipal Fazenda Atalaia (PNMFA - Macaé, RJ). Two areas with different historical use were analyzed. In each area, 30 plots of 100 m² (10 × 10 m) were established and the arboreal plants with DBH > 5cm were recorded and identified. A total of 639 individuals from 118 species, within 86 genera and 39 botanical families, were sampled. The most representative families were Fabaceae, Euphorbiaceae, Myrtaceae, Meliaceae and Sapotaceae, with different proportions of occurrence between the two areas analyzed. Artocarpus heterophyllus Lam. (jackfruit) had the highest values of all parameters in the phytosociological analysis. The basal area of PNMFA is considered medium to high compared to other locations. Despite the invasion by A. heterophyllus and low densities of most species, the two areas seem to be recovering, and with the management of this exotic species, it is possible that the area will preserve a portion of the biological diversity of northern Rio de Janeiro state.
submontane forest; phytosociology; Rio de Janeiro northern region; natural recovery
