Floristic composition and structure of the tree component were analyzed in a coastal peat forest of the National Park Lagoa do Peixe (31º04' - 31º29'S, 50º46' - 51º09'W), located in the central region of the coastal plain of Rio Grande do Sul, Brazil. The tree component was sampled according to the point-centered quarter method, including individuals with a minimum DBH of 5cm. Sixty sample points were distributed along four parallel transects, approximately with the same NE-SW orientation as the lagoon system. Floristic composition resulted in 14 families, 18 genera and 21 species. The total tree density estimated for one hectare was 3,479 individuals. The family with highest species richness was Myrtaceae. The most important species were Syagrus romanzoffiana (Cham.) Glassman, Myrcia multiflora (Lam.) DC., Ilex pseudobuxus Reissek, Citharexylum myrianthum Cham. and Dendropanax cuneatum Decne. & Planch. The species diversity estimated by the Shannon index was 2,601 nats.ind.-1 and the evenness (J) was 0,854, which are similar values to others obtained for peat or swamp forests of southern and southeastern Brazil.
peat forest; tree component; phytosociology
