ABSTRACT
The present work was developed to observe and quantify the possibility of stem gain in five native euxylophorous species [Angico (Parapiptadenia rigida), Canjerana (Cabralea canjerana), Cedro (Cedrela fissilis), Grápia (Apuleia leiocarpa), and Louro (Cordia trichotoma)] in non managed native forests of São João do Polêsine municipality, state of RS. There were studied 17 temporary plots of 10 x 100 m. In the trees of the five elected species for this study, that presented diameter at breast height (dbh) larger than 5 cm, the total height, the commercial height and the potential commercial height of the stems were measured. The stem gain was defined as the difference between the current and potential commercial height, in relation to current commercial height and was expressed in percentage. The average percentile of shaft gain for all the species was larger than 70%, while Louro showed a stem gain significantly smaller than the other species. By a regression analysis (stepwise procedure), mathematical models were selected to describe the stem gain of each species and all the species together. The results showed that there is a potenctial for value adding to the native forest formations of the area, not yet explored by silviculture practices.
Key words:
commercial height of the trees; pruning; formation of the shaft; value of the forest