This work was carried out with the objective of studying the growth in diameter, commercial volume, form factor, mean annual increment of the commercial volume in percentage for two dominant trees of Nectandra megapotamica, in a Decidual Seasonal Forest, located in the municipal district of Santa Maria in the central depression of the State of Rio Grande do Sul, Brazil. The data were obtained from stem analysis and the growth trend in diameter, commercial volume, form factor and mean annual increment of the commercial volume in percentage, were fitted using the models of Mitscherlich & Sontag (1982), Backman (1943), Richards (1959), and a second degree parabolic model. The adjustment of the models indicated that for the diameter and commercial volume, the best model was that one from Mitscherlich & Sontag, for tree number one and for tree number two, the Richard's model presented better adjustment. For the mean annual increment of the commercial volume in percentage, the best model was that one from Backmam, being the parabolic model better for the form factor .
Nectandra megapotamica; stem analysis; growth
