article id 1016,
category
Research article
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.
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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
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Ring,
Skogforsk, The Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden
E-mail:
eva.ring@skogforsk.se
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Högbom,
Skogforsk, The Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden
E-mail:
lars.hogbom@skogforsk.se