Adaptation to climate change in forestry has become a growing concern, in part due to the impact of storms and other events that have raised the awareness of such risks amongst forest owners. Sweden is one of Europe's most densely-forested countries, with this sector playing a major role economically. However adaptation has, to a large extent, been limited to the provision of recommendations to forest managers, most of which have only been partially implemented. This paper summarizes research with direct implications for adaptation to climate change within the forestry sector in Sweden. The focus is based in particular on providing examples of adaptations that illustrate the specific Swedish orientation to adaptation, in line with its relatively intensive forest management system. The paper thus illustrates a specific Swedish orientation to adaptation through active management, which can be contrasted with approaches to adaptation in other forestry systems, in particular those with limited management or management based on maintaining natural forests in particular.
In Sweden, where forests cover more than 60% of the land area, silviculture and the use of forest products by industry and society play crucial roles in the national carbon balance. A scientific challenge is to understand how different forest management and wood use strategies can best contribute to climate change mitigation benefits. This study uses a set of models to analyze the effects of different forest management and wood use strategies in Sweden on carbon dioxide emissions and removals through 2105. If the present Swedish forest use strategy is continued, the long-term climate change mitigation benefit will correspond to more than 60 million tons of avoided or reduced emissions of carbon dioxide annually, compared to a scenario with similar consumption patterns in society but where non-renewable products are used instead of forest-based products. On average about 470 kg of carbon dioxide emissions are avoided for each cubic meter of biomass harvested, after accounting for carbon stock changes, substitution effects and all emissions related to forest management and industrial processes. Due to Sweden’s large export share of forest-based products, the climate change mitigation effect of Swedish forestry is larger abroad than within the country. The study also shows that silvicultural methods to increase forest biomass production can further reduce net carbon dioxide emissions by an additional 40 million tons of per year. Forestry’s contribution to climate change mitigation could be significantly increased if management of the boreal forest were oriented towards increased biomass production and if more wood were used to substitute fossil fuels and energy-intensive materials.
It is well known that a large proportion of available logging residues intended for extraction will not reach the energy-conversion industry, because some are lost during transportation or left on the clear-felled area. However, there is little understanding of where logging residue losses occur in the supply chain. In this study, the distribution of logging residues for two methods (dried- and fresh-stacked method) to extract logging residues were studied in one clear-felled area. In addition, residue fractions were examined in a detailed comparison. Even though the fresh-stacked method left somewhat more logging residues at the clear-felled area, the differences are small between the methods. Approximately 30% of the total amount of logging residues was left behind between the harvester heaps, with an additional 10%-15% under these heaps and approximately 2%-3% beneath the windrows. The final product that was delivered to the energy-conversion industry was very similar, regardless of the extraction method used. The delivered chipped logging residues had moisture contents of 37% and 36% following fresh- and dried-stacked methods respectively, and in both cases the needle content in the processed logging residues was approximately 10%. However, the total amount of fine fractions (needles and fines) was slightly higher following dried-stacking.
Even though the growth rates of most tree species in Sweden is expected to increase in the near future as a result of climate change, increased risks of damage by storms and various pests and pathogens, notably root rot and bark beetles, may also occur. Thus, forest management practices such as changes to thinning regimes, reductions in rotation lengths, and switching to other species (native or exotic) may represent adaptive management strategies to increase the resistance and resilience of Swedish forests to climate change. Clearly, thorough analyses examining the effects of anticipated climatic changes on damage levels, and the potentially relieving effects of possible management adaptations are needed before implementing such changes. In this study, damage caused by storms, root rot and bark beetles (single and in various combinations) under selected climate and management scenarios were simulated in Norway spruce (Pice abies L. Karst) stands. The results indicate that reductions in thinning intensity and rotation lengths could improve both volume production and profitability in southern Sweden. In addition, cultivation of rapidly growing species, such as hybrid larch (Larix × marschlinsii Coaz.) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.), could be as profitable as Norway spruce cultivation, or even more profitable. However, slow-growing species, such as Silver birch (Betula pendula Roth), Downy birch (Betula pubescens Ehrh.) and European beech (Fagus sylvatica L.) indicated low economic output in terms of Land Expectation Value.
The literature contains a large number of bioclimate, climate and biometric models for estimating the production of different species or stands under specific conditions on a defined site or models giving the distribution of a single species. Depending on the model used, the amount of input data required varies considerably and often involves a large investment in time and money. The purpose of this study was to create a model to estimate the annual above-ground biomass production of various species from site conditions defined by mean annual temperature and mean annual precipitation. For this approach, the Miami model of Lieth was used as a base model with some modifications. This first version of the modified model was restricted to sites in Sweden, where changes in the soil and groundwater level were relatively small, and where the growth of land vegetation was mostly dependent on temperature. A validation of this model has shown that it seems possible to use the Miami model to estimate the annual above-ground biomass production of various species, and that it was possible to compare the annual above-ground biomass production of different species on one site, as well as the annual above-ground biomass production of different species on different sites using the modeled data.