Effect of Site Quality and Thinning in Pine Yield

ABSTRACT An experiment in Pinus taeda stands was conducted aiming to evaluate the effect of thinnings and forest site quality on basal area (G), total volume, stem volume (v) and assortment of Pinus taeda. Thinnings occurred between 8 and 9 years old, where the fifth row plus 66%, 54%, 42%, 30% e 19% of the existing trees was cut. Thinnings were followed by measurement of diameters and along the stem to calculate its volume. An analysis of variance in randomized blocks was made adopting the sites as blocks and the mixed thinnings as treatments. Volumetric relation was modeled for the plots and from this, log assortments could be estimated using a software named SISPINUS. In conclusion, thinning affect the volumetric relation especially to larger trees, while its inclination curve reduces from richest sites to poorest sites. Sites exert greater effect than thinnings when considering basal area, total volume, boles volume and volume per assortment.