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Tree regeneration in patch cutting in Norway spruce stands in northern Finland

Valkonen, Sauli, Siitonen, Juha
Scandinavian journal of forest research 2016 v.31 no.3 pp. 271-278
Picea abies, Pinus sylvestris, clearcutting, cutting, experimental design, growing season, natural regeneration, site preparation, surveys, tree growth, trees, Finland
The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37 ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000 ha ⁻¹, of which 1700 ha ⁻¹ crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100 ha ⁻¹, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.