A pilot study of Continuous Cover Forestry in boreal forests: Decreasing the harvest intensity during selection cutting increases piece size, which in turn increases harvester productivity

While even-aged forestry is the dominating forest management system in Sweden, there is an increasing interest in Continuous Cover Forestry. Consequently, the conversion of even-aged stands into uneven-aged ones using e.g. selection cutting can be expected to become more common in Sweden. However, there are no up-to-date studies available on harvester productivity during selection cutting under Nordic conditions. Studying harvest intensity during selection cutting is of interest because lighter harvest intensities lead to higher volume growth and better-preserved forest ambience than heavier intensities. The objective of this study was to examine the effect of harvest intensity on harvester productivity during selection cutting. The field study entailed harvesting either 14%, 28% or 48% of a mature stand's basal area. Harvester productivity was mainly explained by piece size (stem volume), while other factors, including harvest intensity, had only minor effects. This reality means that during selection cutting (thinning from above), piece size increases with decreasing harvest intensity, which in turn increases harvester productivity. Moreover, we observed a mild tendency that operators could select the stems' felling directions and order more freely when fewer trees are harvested. This amelioration increases productivity additionally during lighter harvesting intensities.