The present work is part of studies and researches developed at Long Duration Ecological Project - PELD/CNPq, located in São Francisco de Paula's National Forest (FLONA), RS. The objective of this paper was to identify and to characterize the different stages of succession in mixed rainy forest remains. The work had been accomplished in ten permanent conglomerates of 100m x 100m (10.000m
2), which were divided into ten strips of 10m x 100m (1.000m
2) and these ones subdivided into ten subunits of 10m x 10m (100m
2). In this research, a strip of 10m x 100m was selected for each conglomerate, totaling 100subunits (stands), where it had been installed, at DBH height, dendrometric bands in all trees with CBH ≥ 30cm, for annual diameters measurement. The cluster analysis was accomplished through the Twinspan program, using a data matrix with ninety-nine stands (one of those was unconsidered by the absence of individuals with CBH ≥ 30cm) having as variable the annual increment in diameter (obtained in two years of observations) of sixty nine species. Three floristic groups was obtained, indicating stages of succession in the forest: a group separated a less developed stage of succession denominated secondary forest, being
Nectandra megapotamica
and
Cryptocaria aschersoniana
the indicative species; a second group indicated an intermediate stage of succession in the forest, being
Sebastiania commersoniana and
Ocotea pulchella the indicative species; and a third group of primary forest, whose indicative species was
Araucaria angustifolia.