Vegetation structure in a mangrove forest in Southeastern Brazil

The vegetation structure and spatial distribution pattern of mangrove species was analyzed in 17 study sites using plots in the estuary of the Paraiba do Sul river, located in southeastern Brazil. Only considering individuals > 1 m tall, the average height varied from 5.2 to 14.5 m, the average diameter at breast height varied from 2.6 to 23.5 cm, the basal area varied from 15.1 to 46.4 m 2 .ha -1 and density varying from 732 to 24,060 trunks.ha -1 . There was a greater contribution of basal area in the diameter class >10.0 cm (68%), indicating good structural development of forests. Avicennia germinans (L.) Stearn. was the dominant species in basal area (53%), followed by Laguncularia racemosa (L.) Gaertn.f. (28%) and Rhizophora mangle L. (19%). These species were dominant both at the edge and inside the forest and zonation was not observed. The vegetation structure data indicated that interspecific competition may be influencing the spatial distribution of these mangrove species in the studied area. -1 . Houve maior contribuicao em area basal na classe de diâmetro > 10,0 cm (68%), indicando o bom desenvolvimento estrutural da floresta. Avicennia germinans (L.) Stearn. foi dominante em area basal (53%), seguida por Laguncularia racemosa (L.) Gaertn.f. (28%) e Rhizophora mangle L. (19%). Estas especies foram dominantes tanto na borda quando no interior da floresta, nao havendo zonacao. Os dados indicaram que a competicao interespecifica pode estar influenciando a distribuicao espacial das especies de mangue na area estudada. Palavras chave: estuario, rio Paraiba do Sul, fitossociologia