Productivity of energywood harvesting chain in different stand conditions of early thinnings.

摘要

The objective of this study was to investigate the effects of stand conditions on the productivity of a harvesting machine chain in early thinning stands. The studied harvesting chain consisted of Pro Silva Assa 810 harvester equipped with an accumulating Naarva-Grip 1600-40 felling head and Timberjack 810 forwarder. The study was implemented on two separate stands, which were divided into nine blocks; each with unique stand conditions. The stand densities of the studied blocks varied from 2,000 to 7,750 stems per hectare and average tree length on the blocks were between 5.3-9.9 meters. In these conditions the productivity in cutting varied between 4.7-8.5 m3/h. Average productivity in cutting was 5.8 m3/h. Forwarding productivity was 7.9 m3/h in average varying between 6.0-9.2 m3/h. The increase in stand density and decrease in average stem size reduced less cutting productivity than forwarding productivity compared to separate machine studies.