Regional Nutrient Budgets in Forest Soils in a Policy Perspective
Author
Summary, in English
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 decrease the present carbon dioxide emissions from fossil fuels.
The results highlight several conflicts, not only between production goals and environmental objectives, but also between environmental objectives regarding acidification, eutrophication and emissions of greenhouse gases. The methods of calculating nutrient and carbon budgets are considered suitable for decision support in policy-making, but should preferably be combined with other types of methods, for example, dynamic modelling.
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 decrease the present carbon dioxide emissions from fossil fuels.
The results highlight several conflicts, not only between production goals and environmental objectives, but also between environmental objectives regarding acidification, eutrophication and emissions of greenhouse gases. The methods of calculating nutrient and carbon budgets are considered suitable for decision support in policy-making, but should preferably be combined with other types of methods, for example, dynamic modelling.
Department/s
Publishing year
2005
Language
English
Full text
Document type
Dissertation
Publisher
Department of Chemical Engineering, Lund University
Topic
- Chemical Engineering
Keywords
- 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
Status
Published
Supervisor
- Harald Sverdrup
ISBN/ISSN/Other
- ISBN: 91-7422-076-4
Defence date
4 May 2005
Defence time
13:15
Defence place
Stora hörsalen, Ingvar Kamprad Designcentrum (IKDC), Sölvegatan 26, Lunds Tekniska Högskola
Opponent
- Martin Forsius (Professor)