Karin Johansson, Eva Ring, Lars Högbom. (2013). Effects of pre-harvest fertilization and subsequent soil scarification on the growth of planted Pinus sylvestris seedlings and ground vegetation after clear-felling. Silva Fennica vol. 47 no. 4 article id 1016. https://doi.org/10.14214/sf.1016

Keywords: nitrogen; establishment; regeneration; Scots pine; disc trenching; carryover; competing vegetation

Highlights: Pre-harvest N fertilization had no significant effect on seedling growth and ground vegetation biomass; Scarification improved seedling survival and growth and reduced the amount of ground vegetation; Without scarification, pre-harvest fertilization increased the amount of damaged seedlings.

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Fertilization and scarification are both performed to increase tree production at different stages of forest rotation periods. In this study, the effects of previous nitrogen fertilizations and scarification after clear felling on planted Pinus sylvestris L. seedlings and ground vegetation were investigated. Two fertilization experiments established around 1980 were harvested in 2006, after which the plots were scarified by disc trenching and re-planted. The plots had been repeatedly fertilized over a 20-year period before harvesting, with total N doses of 0, 450, 900 or 1800 kg N ha^-1. After five growing seasons, the growth, survival and nutrient contents of the seedlings were measured, and ground vegetation was collected to estimate its biomass and nutrient content. Pre-harvest fertilization alone had only minor effects on the results, but scarification increased both the survival and growth of the planted seedlings. However, without scarification, seedling mortality increased with increasing fertilization intensity. The ground vegetation biomass was higher in plots without scarification, but the total biomass of seedlings and ground vegetation was similar in all treatments. Scarification thus favored seedling growth at the expense of ground vegetation. Only a few effects on nutrient content were found, but there were no signs of nutrient imbalance in any of the treatments. At higher levels of fertilization, the K:N ratio in the seedlings decreased while the K content in the ground vegetation increased. Overall, scarification had a greater impact than pre-harvest fertilization on the planted seedlings and the ground vegetation.

Johansson, Skogforsk, The Forestry Research Institute of Sweden, Ekebo 2250, SE-268 90 Svalöv, Sweden & Southern Swedish Forest Research Centre, SLU, Box 49, SE-230 53 Alnarp, Sweden E-mail: karin.johansson@skogforsk.se
Ring, Skogforsk, The Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: eva.ring@skogforsk.se
Högbom, Skogforsk, The Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: lars.hogbom@skogforsk.se

article id 146, category Research article

Karri Uotila, Juho Rantala, Timo Saksa, Pertti Harstela. (2010). Effect of soil preparation method on economic result of Norway spruce regeneration chain. Silva Fennica vol. 44 no. 3 article id 146. https://doi.org/10.14214/sf.146

Keywords: Picea abies; soil preparation; cleaning; disc trenching; forestry investment analysis; pre-commercial thinning; regeneration chain; spot mounding; sprouting

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Economic result of forest regeneration chains, based either on spot mounding or on disc trenching and planting of Norway spruce (Picea abies [L.] Karst.) seedlings, were clarified and compared to each other. First, effects of soil preparation method on early development of Norway spruce stands were measured from field experiments. Second, the effects of soil preparation method on stand level management programs were modelled. The modelling was based on growth simulation and investment calculations. The soil preparation methods substantially affected early development of a stand. The density of the removed trees in early cleaning was 56% higher on the disc-trenched area compared to the spot-mounded area. The difference was especially high (120%), close by (< 25 cm) the remained spruce seedlings. There was also a difference between the methods in the growth of crop spruces; at biological age of 8 years, the mean height of spruce was 110 cm on the spot-mounded area and 68 cm on the disc-trenched area. The differences led to divergent management programs between the areas. The disc-trenched area needed three young stand management operations whereas two was enough at the spot-mounded area. Although disc trenching is a less expensive method than spot mounding, the total management costs were higher in disc trenching than in spot mounding. Furthermore, incomes from the first commercial thinning were higher when regeneration based on spot mounding. At the interest rate of 3%, the investment in spot mounding had 329 EUR ha^–1 higher net present value than the investment in disc trenching.

Uotila, Finnish Forest Research Institute, Suonenjoki, Finland E-mail: karri.uotila@metla.fi
Rantala, Finnish Forest Research Institute, Suonenjoki, Finland E-mail: jr@nn.fi
Saksa, Finnish Forest Research Institute, Suonenjoki, Finland E-mail: ts@nn.fi
Harstela, Finnish Forest Research Institute, Suonenjoki, Finland E-mail: ph@nn.fi

Category : Research note

article id 403, category Research note

Timo Saksa, Juha Heiskanen, Jari Miina, Jaakko Tuomola, Taneli Kolström. (2005). Multilevel modelling of height growth in young Norway spruce plantations in southern Finland. Silva Fennica vol. 39 no. 1 article id 403. https://doi.org/10.14214/sf.403

Keywords: Norway spruce; Picea abies; height growth; mounding; disc trenching; container seedlings; intra-level correlation; variance-component model

Abstract | View details | Full text in PDF | Author Info

Height development of Norway spruce (Picea abies (L.) Karst.) transplants was studied on 22 sites prepared by disc trenching or mounding. At the age of 4–9 years the plantations were surveyed using a multistage sampling design. For every planted spruce on a plot, the past annual height increments were measured as far into the past as possible. Multilevel mixed linear modelling was used to analyse the variation in growth at different levels (year, stand, cluster, plot, tree) and the effects of climatic and site characteristics on height growth. The within-plantation variation in height growth was higher on mounded sites than on disc-trenched sites. The mean temperature and the precipitation sum of the summer months affected height growth positively. Soil characteristics measured from undisturbed soil did not explain the height growth of seedlings on mounded sites, whereas on disc-trenched sites, the depth of the organic layer and the soil temperature had a positive effect and the depth of the eluvial horizon a negative effect. The modelling approach used proved to be a useful method for examining the sources of variation in development of young plantations.

Saksa, The Finnish Forest Institute, Suonenjoki Research Station, FI-77600 Suonenjoki, Finland E-mail: ts@nn.fi
Heiskanen, The Finnish Forest Institute, Suonenjoki Research Station, FI-77600 Suonenjoki, Finland E-mail: jh@nn.fi
Miina, The Finnish Forest Institute, Joensuu Research Centre, P. O. Box 68, FI-80101 Joensuu, Finland E-mail: jm@nn.fi
Tuomola, The University of Joensuu, Mekrijärvi Research Station, FI-82900 Ilomantsi, Finland E-mail: jt@nn.fi
Kolström, The University of Joensuu, Mekrijärvi Research Station, FI-82900 Ilomantsi, Finland E-mail: tk@nn.fi

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