This work analyses the tree diametric structure of a Sub-montane Atlantic Forest remnant in Silva Jardim-RJ, Brazil. Twenty 100 m x 5 m plots were established, and all trees with DBH > 5 cm were surveyed. The diametric structure was analyzed for the entire community and its main populations (ordered according to the importance value - VI), using diameter class histograms defined by Spiegel's formula. Species were also grouped within successional categories (Pi: pioneer; SI: early secondary; ST: late secondary). The diametric curves (J-reverse shape) and values of Liocourt's 'q' quotient suggested problems involving lack of regeneration for the main populations for most of the SI species. However, some ST populations (ex. Plathymenia foliolosa and Euterpe edulis) showed a tendency to disappear from the community in the long term, while other SI species became part of the community. These results strengthen the findings of the floristic survey, also suggesting changes in the diametric structure due to the fragmentation process and past disturbance practices. Actions to guarantee protection to the forest remnant and seedling bank enrichment through planting the most threatened tree species are urgently needed for the recovery of the environmental quality of this remnant.
Demographic structure; ecological groups; succession
