Soil preparation method affects outplanting success of Norway spruce container seedlings on till soils susceptible to frost heave

Abstract

Soil preparation method affects outplanting success of Norway spruce container seedlings on till soils susceptible to frost heave Heiskanen J., Saksa T., Luoranen J. (2013). Soil preparation method affects outplanting success of Norway spruce container seedlings on till soils susceptible to frost heave. Silva Fennica vol. 47 no. 1 article id 893. 17 p. AbstractSoil preparation is a common practice that precedes outplanting of Norway spruce (Picea abies (L.) Karst.) in Finland as it enhances the survival and early growth of seedlings. Mounding in particular has become more common with Norway spruce planting in recent years. However, on fine-grained soils, the postplanting performance of seedlings has been poorer than on coarser soils even with mounding. This study examined the effects of different soil preparation treatments (spot and ditch mounding with varying mound height, inverting, unprepared control with or without a herbicide) on the postplanting performance of Norway spruce container seedlings on till soil susceptible to frost heave in two outplanting forest sites in central Finland. The results indicate higher soil temperature and lower soil water content especially in the highest mounds. Mounds, however, subsided gradually during the study years. Seedling mortality was higher and the proportion of vigorous seedlings was lower in the unprepared treatments, mainly due to increased pine weevil (Hylobius abietis L.) damage. Frost heave was present mainly on ditch mounded and inverted spots. Glyphosate herbicide treatment showed no benefit compared to the untreated control in two years. Consequently, seedling damage and conditions in the planting spots were reflected in seedling growth which was enhanced in the mounded spots. However, varying mound height or thickness of mineral capping showed no clear difference in seedling growth. The results therefore suggest that ditch or spot mounding should be used on frost heave susceptible forest soils to promote plantation establishment. Inverting or having no soil preparation with or without herbicide is not recommended.

Influence of spot mounding on height growth and tending of Norway spruce: case study in Latvia

“…Frost heave primarily affects areas on drained peat soils in Latvia (Mangalis, 2004). Study in central Finland found that it has been present mainly on areas with ditch mounded and inverted soil (Heiskanen et al, 2013). Similar to our results, superior height growth of trees planted on mounds had been found also in numerous studies in Sweden and Finland (Saarinen, 2007;Lehtosalo et al, 2010;Uotila et al, 2010;Hallsby & Örlander, 2013).…”

“…These fi ndings are in line with our results where largest height differences were found between spruces growing on mounds and on unprepared soil (Figure 3). Lack of soil scarifi cation leads to much more frequent pine weevil damages even if the plants are treated by insecticide in the nursery (Heiskanen et al, 2013). For example, study in Finland had found 76% of Norway spruce seedlings gnawed in unscarifi ed spots during fi rst growing season in fi eld in contrast to only 1% gnawed on mounded spots (Heiskanen & Viiri, 2005).…”

“…Also other studies have concluded that mounds creates favourable moisture regime that is essential for early survival of Norway spruce (Schlyter et al, 2006). Planting on mounds improves not only the survival, but also initial growth of the trees (Nordborg et al, 2003;Hallsby & Örlander, 2013;Heiskanen et al, 2013). Young trees on mounds are less likely to be affected by frosts (Langvall et al, 2001;Heiskanen et al, 2013) and better protected from pine weevils (Örlander et al, 1990;Heiskanen & Viiri, 2005;Saksa, 2008;Heiskanen et al, 2013) that tend to avoid rather large open soil area around the seedling (Wallertz, 2009).…”

“…Also studies indicate that planted spruce stands have considerably higher productivity than naturally regenerated ones (Gradeckas & Malinauskas, 2005). It is achieved partly due to realization of tree breeding results (Jansons et al, 2015) and partly due to positive infl uence of soil preparation (Nordborg et al, 2003;Heiskanen et al, 2013).…”

“…Planting on mounds improves not only the survival, but also initial growth of the trees (Nordborg et al, 2003;Hallsby & Örlander, 2013;Heiskanen et al, 2013). Young trees on mounds are less likely to be affected by frosts (Langvall et al, 2001;Heiskanen et al, 2013) and better protected from pine weevils (Örlander et al, 1990;Heiskanen & Viiri, 2005;Saksa, 2008;Heiskanen et al, 2013) that tend to avoid rather large open soil area around the seedling (Wallertz, 2009). Furthermore, mound excluded competition from surrounding vegetation for a longer period of time than furrows (Lehtosalo et al, 2010).…”