Climate mitigation potential of the Swedish forest under different forest management regimes and levels of substitution effect

Sammanfattning: The Swedish forest is currently being debated as to how it should be managed to provide climate mitigation. Forest management can contribute to climate mitigation in mainly two ways. Either through increased sequestration and storage of carbon in the forest or as a consequence of the substitution effect, through which emissions can be avoided by utilizing harvested wood products to replace other emission-intensive products. However, these two climate benefits are at odds with each other, as efforts to increase the sequestration of carbon in the forest by increased conservation will decrease the amount of harvested biomass available for substitution. This fact has led to a disagreement between scholars regarding the climate benefits of increased forest conservation versus the climate benefits of maintaining a high harvest level. The climate benefit of increased forest conservation is influenced by how much additional carbon the growing forest can sequester over time. The climate benefit of forest harvest is instead directly related to the level of achieved substitution effect. As the substitution level is dynamic, it may change in the future due to various technological, economic, and societal developments, which would influence the potential climate benefit of forest harvest. In addition, intensifying forest management as a means to increase forest growth is also commonly suggested as a possible measure for enhancing the climate mitigation potential of the Swedish forest. This study aimed to investigate how the climate mitigation potential of different forest management regimes develops over time based on different potential levels of achieved substitution effect. Based on input data from the National Forest Inventory, the Heureka RegWise system was used to simulate the impact on sequestration of carbon dioxide and the available harvested biomass to be used for substitution for the different forest management regimes over a 150-year period. The results indicate that increased forest conservation provides a higher climate mitigation potential throughout a majority of the 150-year period. However, the climate benefit of increased conservation does diminish over time due to the set-aside forests' declining ability to sequester additional carbon. The rate at which the forest management regimes without increased conservation can catch up is influenced on which level of substitution that is applied. The results also indicate that increased utilization of growth-enhancing practices increases the climate mitigation potential of forest management.