The effect of planting, seeding and soil preparation on the regeneration success of Scots pine (Pinus sylvestris L.) on drained peatlands – 10-year results

We studied the effect of regeneration (planting/seeding) and soil preparation methods (no soil preparation/scalping/mounding) on the regeneration success of Scots pine (Pinus sylvestris L.) on three drained peatland Scots pine stands in northern Finland. After ten years, planting and sowing showed no differences in the total number of Scots pine seedlings (one seedling per sowing spot accepted) with the exception of the Sievi experiment. Without soil preparation the total number of Scots pine seedlings was 350–600 per ha. Scalping increased the number of Scots pine seedlings to 550–900 per ha, with the exception of seeding at Sievi. In mounded plots, with the exception of seeded plots at the Sievi site, the number of planted or seeded seedlings was 1,325–2,350 per ha. The number of crop seedlings in all the experiments and for all the soil preparation treatments reached the target of 2,000 seedlings per ha if naturally regenerated Scots pine, Norway spruce (Picea abies (L.) H. Karst.) or birch (Betula spp.) seedlings were accepted as such. Moose (Alces alces L.) damage in Scots pine crop seedlings ranged from 4% in Sievi to 65% in Simo. The proportion of planted or seeded Scots pines of the crop seedlings was 23% in unprepared plots, 30% in scalped plots and 75% in mounded plots. Mounding increased the share of Scots pine seedlings in the overall crop seedlings. Planted seedlings were taller than seeded seedlings. Planting in mounds gave the best overall results in terms of the number of crop seedlings and their height ten years after the treatment.