Above ground pruning, aiming better quality of seedlings of Pinus taeda, in Caçador, SC

Abstract

The objective of this paper was to evaluate the effects caused by the above ground pruning over the survival, height (h), neck diameter (d_n) and h/d_n relation, of Pinus taeda L. seedlings, in the municipal district of Caçador, Santa Catarina State, Brazil, aiming to obtain seedlings of better quality. Six different types and intensities of pruning were tested. The data were analyzed by the variances homogeneity test (Bartlett´s test), variance analysis (ANOVA) and, by the Tukey´s test of means comparison (α = 5%). Sixty days after the experiment installation, there was no seedlings mortality ; the removal of the upper portion of the seedlings showed abundant formation of side shoots, significant decrease of seedling heights and h/d_n relation, improving the quality pattern of the seedlings. On the other hand, the removal of the lower portion of seedlings leaves caused significant increase of heights, but did not affect the h/d_n relation. None of the treatments resulted in significant increase in neck diameter. However, the most intensive above ground pruning (upper portion removal + removal of the 2/3 of the lower portion of leaves) caused significant reduction of the neck diameter and, consequently, of the seedlings quality.