Regional Nutrient Budgets in Forest Soils in a Policy Perspective

• Main Author: Akselsson, Cecilia
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Department of Chemical Engineering, Lund University 2005
• Subjects: Chemical Engineering; pedology; cartography; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; klimatologi; geomorphology; Physical geography; Miljökemi; Environmental chemistry; skogsteknik; skogsbruk; Skogsvetenskap; forestry technology; forestry; Silviculture; Näringslära; Nutrition; Växtekologi; policy-making; Plant ecology; regional scale; deposition; eutrophication; carbon sequestration; acidification; Nutrient budget; Northern Sweden
• Online Access: https://lup.lub.lu.se/record/544693; https://portal.research.lu.se/files/4627511/544694.pdf

Sweden's forests are one of its most important natural resources, as well as being important from ecological and social perspectives. Nutrient sustainability is essential to maintain the production capacity and reduce the effects of acidification and eutrophication. Nutrient sustainability is strongly affected by anthropogenic influences such as air pollution and forestry practices. Regional assessments of the nutrient sustainability with different deposition and harvesting scenarios are thus required in policy-making. This thesis deals with the nutrient sustainability regarding nitrogen, calcium, magnesium and potassium on a regional scale in Swedish forests, and the potential effects of forests on carbon sequestration. It includes method development of regional weathering rate modelling, regional budget calculations for Sweden, and a discussion of the results in a policy context. Estimates of base cation budgets showed that the pools of exchangeable base cations are decreasing and that the stores are being depleted at rates that could lead to negative effects within the period of one forest rotation. The whole-tree harvesting scenario indicated substantially higher base cation losses than the stem harvesting scenario in spruce forests, while the losses were significantly lower in pine forests. The nitrogen budget calculations indicated a risk of nitrogen leaching in southern Sweden and increased nitrogen shortage in northern Sweden. Consequently, policies affecting the supply of nitrogen must take into account regional differences if they are to be effective. Calculations showed that carbon sequestration in Swedish forest soils is not an effective way of decreasing national net carbon dioxide emissions, since the long-term capacity is low and involves the accumulation of nitrogen, increasing the risk of acidification and eutrophication of aquatic and terrestrial ecosystems. Whole-tree harvesting, combined with the use of branches, tops and needles as biofuel to replace fossil fuels, would substantially ...