Edge presence and orientation drive wind-induced mortality in Swedish forests

Abstract Key message Newly created forest edges, particularly those facing westerly winds, substantially raise the risk of wind damage in Swedish forests. Taller and spruce-dominated stands are more vulnerable. Integrating edge orientation and harvest timing into long-term management planning can lower vulnerability and strengthen forest resilience to increasing storm impacts under future climate conditions. Context Windstorms are a major disturbance in boreal forests. Although future storm conditions remain uncertain, forest vulnerability to wind damage may increase regardless due to altered growth rates, soil conditions, and management practices. Understanding how different factors influence wind risk is therefore essential for adaptive management. Aims This study aimed to determine the relative importance of edge orientation, stand structure, and management history in explaining wind-induced mortality in Swedish forests. Materials and methods We analyzed data from over 57,000 permanent plots in the Swedish National Forest Inventory (2003–2022) using a generalized linear mixed-effects model. Stand height, species composition, thinning intensity and timing, and the presence and direction of new stand edges were evaluated in relation to wind damage probability. Results Newly created stand edges markedly increased the probability of wind damage, particularly those facing prevailing westerly winds. Stands with taller trees and a higher proportion of Norway spruce ( Picea abies ) were more susceptible. Thinning within 5 years slightly increased risk, whereas thinning 6 to 10 years earlier reduced it. Conclusions Edge presence and orientation emerged as the strongest determinants of wind vulnerability. Planning harvests to limit newly exposed windward edges, while coordinating thinning timing, can substantially reduce storm risk and enhance forest resilience under future climate conditions.