Table 2. Definitions of thinning treatments in the experiments. In all treatments, the width of the strip road was between 4.0–4.5 m, and the strip roads were pre-marked in the centre of the plot. In selective thinning (Sel) treatments, the areas between strip roads were thinned from below, where primarily, the smallest, poorer and possibly damaged trees were removed. In systematic boom-corridor (BCTp, BCTf) treatments, 2.5-m-wide corridors, with 7 m between the machine position, were harvested. In all BCT treatments, the areas between the corridors were left untreated.
Treatment Definition
Sel1 Selective thinning. Pre-clearing of undergrowth was not needed.
Sel2 Selective thinning, pre-cleared. The undergrowth hindering harvester work was removed before test cutting.
BCTp Completely systematic perpendicular boom-corridor thinning. Pre-clearing of undergrowth was not needed. Corridors 90o from each machine position were harvested. The trees to be removed from the corridors were marked with a sign.
BCTf Completely systematic fan-shaped boom-corridor thinning. Pre-clearing of undergrowth was not needed. Corridors 30o from each machine position were harvested. The opposite corridors of the machine positions were staggered at 2 m. The trees to be removed from the corridors were marked with a sign.
BCTsemi1 Semi-selective boom-corridor thinning. Pre-clearing of undergrowth was not needed. In the middle of the plot, the advisory corridor locations on opposite sides of the strip road were marked. The width and distance of the corridors were, on average, the same as in BCTp and BCTf. The operator chose the exact location of the corridors based on the standing trees. The trees to be removed from the corridors were not marked.
BCTsemi2 Semi-selective boom-corridor thinning, pre-cleared. The undergrowth hindering harvester work was removed before test cutting. In the middle of the plot, the advisory corridor locations on opposite sides of the strip road were marked. The width and distance of the corridors were, on average, the same as in BCTp and BCTf. The operator chose the exact location of the corridors based on the standing trees. The trees to be removed from the corridors were not marked.
BCTsemi3 Semi-selective boom-corridor thinning, no pre-clearing. The undergrowth hindering harvester work was not removed before test cutting. In the middle of the plot, the advisory corridor locations on opposite sides of the strip road were marked. The width and distance of the corridors were, on average, the same as in BCTp and BCTf. The operator chose the exact location of the corridors based on the standing trees. The trees to be removed from the corridors were not marked.
BCTsel Selective boom-corridor thinning. Pre-clearing of undergrowth was not needed. The width and distance of the corridors were, on average, the same as in BCTp and BCTf. The operator independently chose the location of the corridors based on the standing trees.