Thinning from below: effects on height of dominant trees and diameter distribution in eucalyptus stands

Abstract

This study aimed to evaluate the height and diameter growth of dominant trees in eucalypt plantations submitted to thinning from below. The thinning experiment was carried out in the north-east Bahia, Brazil in sites with different productive capacities. The treatments corresponded to a reduction of 20, 35, 50% of stand basal area and an additional treatment of 35% removal plus pruning. We evaluated the growth inheight before and after thinning, the dominant height × mean diameter ratio and the diameter distribution over time. There was no statistical difference in dominant height growth before and after thinning and neither between treatments, which allowed for the use of a single equation to represent dominant height growth. The average diameter and distribution of individuals across the diameter classes, on the other hand, were influenced by thinning weight. Our study reinforces that site index, as the mean dominant height at a reference age, would be used even after the application of thinning given that dominant height was not affected by this silvicultural treatment.