Highlights • Annual growth is 287 million m 3 in the forests of the Nordic and Baltic countries. • Growth can be increased by new tree species, tree breeding, high-productive management systems, fertilization and afforestation of abandoned agricultural land. • We predict a forest growth increment of 50-100% is possible at the stand scale. • 65% of annual growth is harvested today.

No abstract

In this work, we studied the potentials offered by managed boreal forests and forestry to mitigate the climate change using forest-based materials and energy in substituting fossil-based materials (concrete and plastic) and energy (coal and oil). For this purpose, we calculated the net climate impacts (radiative forcing) of forest biomass production and utilization in the managed Finnish boreal forests (60°-70°N) over a 90-year period based on integrated use forest ecosystem model simulations (on carbon sequestration and biomass production of forests) and life-cycle assessment (LCA) tool. When studying the effects of management on the radiative forcing in a system integrating the carbon sink/sources dynamics in both biosystem and technosystem, the current forest management (baseline management) was used a reference management. Our results showed that the use of forest-based materials and energy in substituting fossil-based materials and energy would provide an effective option for mitigating climate change. The negative climate impacts could be further decreased by maintaining forest stocking higher over the rotation compared to the baseline management and by harvesting stumps and coarse roots in addition to logging residues in the final felling. However, the climate impacts varied substantially over time depending on the prevailing forest structure and biomass assortment (timber, energy biomass) used in substitution.

We employed a forest ecosystem model (SIMA) to study how the changes in forest conservation area and management affect the volume growth, harvested amount of timber, carbon stock, and amount of deadwood in Finnish boreal upland forests under current and changing climates (RCP4.5 and RCP8.5) over 2010–2099. Simulations were carried out on National Forest Inventory plots using three different forest conservation scenarios (baseline and 10% and 20% increases of conservation area) and three thinning regimes (baseline and maintenance of ±20% stocking in thinning compared with recommendations). An increase of forest conservation area increased the volume growth, carbon stock, and quantity of deadwood in forests, as did the maintenance of 20% higher stocking in thinning. Maintenance of 20% lower stocking in thinning increased, in general, the amount of harvested timber, but it could not compensate for the decrease of harvested timber due to increase of conservation area. Climate warming greatly increased all of the studied variables in northern Finland but decreased them in southern Finland, the most under the strongest climate warming scenario, RCP8.5. Climate warming also increased the quantity of deadwood throughout Finland. To conclude, we found clear trade-offs for production of different ecosystem services.

We studied the effects of climate change and forest management scenarios on net climate impacts (radiative forcing) of production and utilization of energy biomass, in a Norway spruce forest area over an 80-year simulation period in Finnish boreal conditions. A stable age-class distribution was used in model-based analyses to identify purely the management effects under the current and changing climate (SRES B1 and A2 scenarios). The radiative forcing was calculated based on an integrated use of forest ecosystem model simulations and a life cycle assessment (LCA) tool. In this work, forest-based energy was used to substitute coal, and current forest management (baseline management) was used as a reference management. In alternative management scenarios, the stocking was maintained 20% higher in thinning compared to the baseline management, and nitrogen fertilization was applied. Intensity of energy biomass harvest (e.g. logging residues, coarse roots and stumps) was varied in the final felling of the stands at the age of 80 years. Also, the economic profitability (NPV, 3% interest rate) of integrated production of timber and energy biomass was calculated for each management scenario. Our results showed that compared to the baseline management, climate benefits could be increased by maintaining higher stocking in thinning over rotation, using nitrogen fertilization and harvesting logging residues, stumps and coarse roots in the final felling. Under the gradually changing climate (in both SRES B1 and A2), the climate benefits were lower compared to the current climate. Trade-offs between NPV and net climate impacts also existed.