Scientific publications

Long-term changes in stand structure and productivity, as well as the features of natural regeneration in a mixed bilberry-type Scots pine stand subjected to high-intensity selection cutting in 1996, were analysed. Compared with the control, the harvested stand showed an increase in stand density due to active recruitment of Norway spruce from advance regeneration into the main stand layer. During the same period, the control stand exhibited a decrease in stand density, mainly due to the loss of Scots pine and birch. Mean diameter and height increased in both plots; however, growth increments were consistently higher in the selectively cut stand. Twenty-seven years after harvesting, the growing stock recovered to 86 % of its initial level, while the current increment rates substantially exceeded those observed in the control plot. The increment averaged over the entire post-harvest period was 4.8 m³ha^–1yr^–1, the average during the last measurement interval (9 years) being 6.6 m³ha^–1yr^–1. The respective figures for the control plot are 1.6 and 1.4 m³ha^–1yr^–1. Selection cutting had a positive effect on the natural regeneration of tree species, including conifers. Twenty-seven years after harvesting, the total density of Scots pine and Norway spruce regeneration reached 2.6 thousand individuals ha^–1, which was four times higher than in the control plot. Of these, 0.4 thousand individuals ha^–1 belonged to the large-size regeneration category, indicating favourable prospects for maintaining the species composition and the formation of a complex vertical stand structure. The results presented in this study demonstrate the effectiveness of selection cutting in protective mixed mid-boreal coniferous–deciduous stands for maintaining stand stability and ecosystem functions, as well as the possibility of sane and sustainable utilization of timber resources.