Germination and seedling establishment of Norway spruce (Picea abies) after clear-cutting is affected by timing of soil scarification

Abstract

Natural regeneration of Norway spruce (Picea abies (L.) Karst.) is a relatively common practice in Norway on medium to low site indices. However, seedling establishment is often hampered by rapid regrowth of competing vegetation in scarified patches. The aim of our study was to examine the effect of coordinating scarification towards an expected seed-fall, by studying germination and seedling establishment in scarified patches of different age (fresh, one-and two-year-old). The experiment was conducted in two stands in southeast Norway that were clear-cut in 2007. Scarification was applied to subplots in autumn 2008-2010. To simulate seed-fall, seeds were sown in fresh scarification patches in spring 2009-2011, in one-year-old patches in 2010 and 2011, and in twoyear-old patches in 2011. Both germination and seedling survival were negatively affected by the age of the scarified patches. Germination was higher, and mortality lower, at the small fern woodland site, compared with the bilberry woodland site. Sowing in fresh patches also resulted in increased height and root collar diameter of the seedlings compared with sowing in older patches. It is likely that the competing vegetation both on the site and in the scarification patches affected the growth of the seedlings. In conclusion, the age of the scarified patches affected both germination and mortality, as well as early growth of the seedlings.

Comparison of Norway spruce artificial regeneration techniques tested in the area destroyed by spruce bark beetle in Kysuce Region (Slovakia)

“…In this study, placement of seed into the substrate regardless of seeding treatment (VCS, DS) had probably stimulating effect on germination as well as initial establishment success of germinated seedlings. First year seeding spot occupation rate reaching 72% for DS and 98% for VCS markedly outperform findings of Erefur et al (2008) and Fløistad et al (2018) with less than 40% germinated spruce seeds seeded directly into the mineral soil. Furthermore, germinated seedlings have showed also high initial adaptation ability to field condition reaching stem height and root collar diameter of nursery grown spruce seedlings of corresponding age (Slávik 2005;Vaario et al 2009).…”

Natural Regeneration of the Tree Stand in the Bilberry Spruce Forest—Clear-Cutting Ecotone Complex in the First Post-Logging Decade

“…The issue of natural recovery after logging of boreal forests has been studied quite well [32][33][34][35][36] etc. In poor conditions of lichen and cowberry pine forests on sandy soils, cuttings are overgrown with pine [37,38].…”

Various scarification treatments produce different regeneration potentials for trees and forbs through changing soil properties

“…Furthermore, natural regeneration has various economic advantages compared with planted forests, as tree species that are difficult to grow by planting (e.g., many broadleaf species) can be produced and management costs can be reduced by eliminating the need for planting operations (Shono et al 2007;Gonza´lez-Rodrı´gues et al 2011). However, there is a major disadvantage in natural regeneration, i.e., its reliance on natural seed dispersal; its success varies depending on the level of seed production and the suitability of the understory conditions (Löf et al 2012;Fløistad et al 2018). Therefore, assistance practices are often employed to improve the site conditions for seed germination and seedling establishment (Löf et al 2012;Nyland 2016).…”

“…When carrying out scarification, an appropriate method should be used that considers both the site conditions and species characteristics. Indeed, scarification has occasionally been shown to have a negative effect on the target species, with regeneration failing in some instances, likely due to the vigorous growth of competitive vegetation, such as tall forb species (Zaczek 2002;Yoshida et al 2005;Fløistad et al 2018). Therefore, a quantitative evaluation of the influence of scarification on not only the target tree species but also competitive vegetation is required.…”