Modeling and optimizing alpine forest management to maximize carbon sequestration

Forests affect the Earth’s carbon cycle in different ways: by absorbing carbon into biomass and soils, by transferring carbon to the pool of harvested wood products (HWP), and by allowing some of these products to save emissions by replacing climate-intensive materials. However, management also affects the forest carbon balance in more subtle ways, such as by modifying the age structure of the forest and hence the strength of its carbon sink, and by influencing the occurrence of natural disturbances, which could reduce future sink capacity. A comprehensive estimate of the effects of forest management on climate mitigation needs to integrate all these factors, but studies that jointly take into account all this information are rare. Thus, it remains unclear what strategy maximizes climate mitigation for each forest. We couple a forest dynamic model, which simulates future forest growth, harvest and disturbance in two mountain forest catchments, to an optimisation algorithm that explores the strategy space for maximum cumulative climate mitigation up to 2100. Our optimized management generates an additional climate mitigation potential of 9.2 to 10.2 tCO2 ha− 1, compared to current management. Our results consistently prioritised stand-level carbon retention, highlighting the dominant role of retaining carbon in living biomass, and the secondary benefit from HWPs and substitution when integrated judiciously. Also, the optimal mix of interventions varies among stands and forest-cover types, demonstrating that there is no one-size-fits-all solution. Altogether, the study demonstrates that coupling landscape-level forest modelling with formal optimisation provides a robust framework for evidence-based, climate-smart forest management and planning. Finally, the study proposes a comprehensive approach with the aim of including all relevant processes in the assessment of the carbon-related climate change mitigation potential of forests, with recommendations for action for all major types of alpine forests present in the study area.