THE EFFECT OF INITIAL STAND DENSITY ON CLEAR WOOD YIELD IN Loblolly pine PLANTATIONS

Abstract

This paper  analyzed  the influence of initial stand density on mean tree dbh, mean top height, mean height at the lowest branch, mean total tree volume, clear mean volume, mean volume at 25 cm, 18 and 8 cm diameter, in loblolly pine plantations in southern Brazil. Special attention is given to clear wood yield. The experiment was established in the Jaguariaíva county, Paraná State, on the Pisa Florestal S.A. lands. The experiment was evaluated at several occasions since its establishment, but onlydata collected in the last measurement (1999, at age 12) were used. The results indicated that large inital spacing determine more remarkable increase in dbh and other related variables (mean total tree volume, mean volume at 25 cm, 18 and 8 cm diameter). No significant effect of stand density on mean top height was noticed. It was also noticed that stand density affects knot formation; the higher the density the lower the height at the lowest branch and the lower the clear volume. It was concluded that if the key objective is wood yield for veneer (and sawnwood in some cases), it is recommendable to use larger stand spacings in combination with artificial prunning. When pruning is not feasible, the intermediate spacings (as 2.5 x 2.8 m) should be used, which may result in same clear wood yield as compared to larger spacings (as 2.5 x 3.6 m or larger).