Forest density and thinning intensity effect in mechanized thinning with harvester.

Abstract

The objective of this study was to evaluate how forest density and thinning intensity affect the harvester work performance. Were studied seven different harvesters, in nine situations of second thinning of pine, from northeast Argentina. Time studies comprises the establish of plots and the filming of operations. Forests have an average density of 656 trees.ha-1, with a mean volume of 0.53 m3. In thinning’s, a 45% of the trees were removed. Mixed plot-level models were adjusted for each activity, incorporating the forestry and operation characteristics as fixed factors, and the site as a random factor. The effective productivity was between 11 and 46 m3.h-1. A higher forestry density implied a reduction in time for reach the trees and an increase in the time required for head positioning, delimbing and bucking. In contrast, an increased in thinning intensity reduced the time for reach the trees and implied the harvesting of larger trees, with a positive impact on productivity. The elaboration of several products implied a reduction of 21.6% in productivity with respect to the any pulpwood assortment.