Hannu Hökkä , Jaakko Repola, Mikko Moilanen, Markku Saarinen

Seedling establishment on small cutting areas with or without site preparation in a drained spruce mire – a case study in northern Finland

Hökkä H., Repola J., Moilanen M., Saarinen M. (2012). Seedling establishment on small cutting areas with or without site preparation in a drained spruce mire – a case study in northern Finland. Silva Fennica vol. 46 no. 5 article id 920. https://doi.org/10.14214/sf.920

Abstract

A large proportion of drained spruce mire stands is currently approaching regeneration maturity in Finland. We studied the effect of cutting – small canopy openings (78, 177, and 314 m²) and small clear-cuts (0.25–0.37 ha) – with or without site preparation (scalping) on the establishment of natural Norway spruce seedlings in one experimental drained spruce mire stand in northern Finland. The cuttings were made in winter 2004–2005 and site preparation with scalping in early June 2005. The experimental design was composed of four blocks with altogether four clear-cuts and 33 canopy openings. The seedling establishment was surveyed annually (2006, 2008–2010) from five circular sample plots (one 10 m² and four 5 m² plots in size) located within the canopy openings and from 18 circular 5 m² sample plots systematically located in the scalped and untreated halves of the clear-cuts. Site preparation was found unnecessary, because it resulted in a clearly lower number of seedlings in the openings. A slight negative effect was also found in the clear-cuts. In the two years following the cuttings, the number of seedlings increased quickly in the canopy openings, but more gradually in the clear-cut areas. In 2010, on average 15 500 new seedlings were observed in the canopy openings and 6700 in the clear-cut areas, of which 5050 and 1200, respectively, were >0.1 m tall spruces. The proportion of birch increased in the last two years, being ca. 22% in the openings and 45% in the clear-cuts in 2010. The spatial distribution of seedlings was more uneven in the clear-cuts than in the openings, with 41% and 20% of survey plots empty, respectively.

Keywords
Picea abies; site preparation; canopy gaps; natural regeneration; drained peatlands; seedling establishment; clear-cut

Received 12 September 2012 Accepted 22 November 2012 Published 31 December 2012

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