Forest management strategies for CO₂ mitigation

The concentration of greenhouse gases in the atmosphere has increased since pre-industrial time and a further increase is expected to lead to profound global climate change. Forests can play an important role in counteracting green house gas emissions as they are ubiquitous and are one of the currently available mechanisms for mitigating the increase of atmospheric CO₂. This thesis focuses on how carbon sequestration considerations can be incorporated in forest management analysis and planning. In Paper I the carbon status of forest biomass and soil in forest stands in southern Sweden were scrutinized under various thinning regimes and fertilization programmes. Biofuel production was also considered. Thinning and biofuel harvest decreased on-site carbon sequestration. Off-site forest carbon storage in products and fossil fuel substitution were, however, not considered. In Paper II an optimizing model that could handle a large forest area and the monetary value for carbon sequestration was presented. The objective was to maximize the net present value of harvested timber, biofuel production and carbon sequestration. The model was applied to the county of Västerbotten (3.2 million hectares) in northern Sweden using Swedish National Forest Inventory data. Applying a monetary value to carbon sequestration increased carbon storage and decreased harvest levels. In Paper III the model developed in the previous paper was used to model short–and long-term potential carbon sequestration together with timber and biofuel production. In-depth analyses of the same data set as in Paper II, i.e., the county of Västerbotten, were performed. Carbon prices ranged from zero up to the same level as the Swedish carbon dioxide tax (2310 SEK per tonne C). Harvest levels ceased at about 1000 SEK per tonne C. The decrease in harvest was more pronounced in the western low productive areas of the county. The focus in Paper IV was to investigate the impacts of climate change uncertainty in solutions to forest management problems for typical Swedish stands. Only the effect of raised temperature was considered. The economic value increased almost 5 % when the maximum temperature trend (+6.0°C) was applied, compared to the value under the minimum trend (+2.5°C). However, the economic importance of optimizing management plans according to the correct temperature scenario appeared to be limited.