Möjligheter till ökat uttag av skogsbränsle (GROT) i Västerbottens och Västernorrlands län: - Produktionsnedsättningar hos gran och tall samt möjligheter till näringskompensation
Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
The possibility for an increased extraction of logging residues in Västerbotten and Västernorrland. Production decreases with spruce and pine and possibilities for nutrient compensation
Ethanol can be produced from logging residuals, especially from coniferous trees. The harvesting of the residuals causes only a small reduction of the total biomass in the forest but at the same time it is a big reduction of the nutrients forest. This study describes how the growth of the trees is affected by the extraction of the nutrients and what possibilities there are to compensate that loss within the region. A theoretical model showed that harvesting of logging residuals would cause a loss of base cat ions and nitrogen. Several of the field studies show that harvesting led to a growth reduction, caused by a lack of nitrogen. The survival rate of the seedlings was higher after extraction of logging residuals then after conventional clear cutting. Generally speaking all studies indicate that scots pine is less sensitive to extraction of logging residuals than the norway spruce. Since it seems to be nitrogen that causes growth reductions there is a need for nitrogen fertilization. Nitrogen fertilization gives an increased growth for 8-10 years. Nitrogen fertilization can however cause nitrogen leakage in poor soils. To compensate the growth reduction with sewage can be viewed as preferable from a recycling standpoint, but sewage contains almost no nitrogen at all. The Swedish National Board of Forestry recommends spreading of wood ash after extraction of logging residuals, but wood ash seems to cause a lower growth. The change from a fossil fuel to a bio alcohol fuel is only a small step towards sustainable society.
Place, publisher, year, edition, pages
2004. , 46 p.
coniferous stands, whole-tree harvesting, logging residues, nutrients, fertilization
IdentifiersURN: urn:nbn:se:umu:diva-32192OAI: oai:DiVA.org:umu-32192DiVA: diva2:301430
Holm, Stig-Olof, PhD