ABSTRACT
The effect of different thinning intensities on the production of Eucalyptus grandis HILL ex Maiden, planted in 1981, with a spacing of 3.0 x 2.0 m, in Cachoeira do Sul, Rio Grande do Sul, was studied in a randomized block design, in four treatments with two repetitions: control treatment, without thinning, and maintenance of 40%, 50% and 60% of the basal area proportionally to the control. Significant differences among the treatments were detected with 5% probability. Maximum yield (756.2 m3cc/ha) was obtained on the control, which was not statistically different from the treatment with 60% of the basal area (639.6 m3cc/ha) only. The reduction in the basal area increased the concentration of the frequencies of the larger diameter classes, skewing the distribution to the right; however, there was an expressive loss of total yield and a significant increase in diameter. The maintenance of 60% of the basal area allowed the least loss of production, at about 15.4%, and an increase of 6.4 cm or 23.9% in diameter of the remaining trees when compared with the control.
Key words:
Thinning; yield; Eucalyptus grandis