Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha⁻¹), and 36% were at least satisfactory (≥1300 ha⁻¹). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.

Keywords:

• Competition
• partial harvesting
• patch clear-cutting
• Picea abies
• stand edges
• understorey vegetation

Acknowledgements

The study was based on the set of experiments established in terms of the MONTA project. We are grateful to the MONTA participants, the MONTA financiers, and the landowners (Metsähallitus, Metsämannut, Tornator, and UPM) for providing the study sites and implementing the treatments, and Metsämiesten säätiö for financial support for this particular study. Markus Strandström, Heikki Pajuoja, and Jari Varjo deserve our special gratitude for promoting the effort at all stages, and Ilkka Taponen, Erkki Salo, and Veijo Salo for their inexorable endeavor in the field. The results support the MC IF project RESTORE (236030) within the EU 7th Framework Program.