Hot and dry conditions following wildfires can make it difficult for forests to regrow. Researchers, led by North Central CASC affiliate Dr. Kim Davis, compiled a large dataset to test how wildfire severity levels and post-fire environmental conditions affect the regeneration of eight conifer species in the western United States. The dataset included information from over 10,000 field locations from 334 wildfires that have occurred over the past four decades. The study published in PNAS demonstrated that hotter and drier conditions after fires do lower the ability of trees to regenerate, and that this is especially true after high-severity fires: fewer seeds survive hotter fires, and those that do survive face harsh conditions. This is a destructive combination for forests that are expected to continue to experience intense fires. Managers could consider forest treatments like forest thinning to lower the severity of future fires and possibly offset these negative effects of climate change on forest regrowth. Managers in the western United States can use the predictive maps generated from this NC CASC-supported study to identify which species and forests face the highest risks in coming decades, and to inform their management plans. 

This work is supported by the North Central CASC project, “Anticipating Forest Vulnerability to Fire-Catalyzed Ecosystem Change in the Northern Rocky Mountains.”