Resilience and regeneration after wildfire in dry mixed-conifer forests of the U.S. northern Rockies

<p>Presentation given to the Northern Rockies Fire Science Network on Feburary 26, 2015.</p> <p>Over the past several decades, increases in area burned in the western U.S. have caused considerable concern about forest resilience following large wildfires. This concern is especially pronounced in dry mixed-conifer forests, where the combined effects of 20th century land management and land use have altered species composition, fuel loads, and fire regimes.</p> <p>This research documents patterns of post-fire regeneration of tree species across gradients in elevation, latitude, aspect, and burn severity in dry-mixed conifer forests of the US Northern Rockies burned 5 to 13 years prior. We investigated how different landscape characteristics (e.g., topography, elevation) interacted with legacies of the fire environment (e.g., burn severity, patch size, canopy cover) to influence where trees regenerate following large, mixed-severity fires.</p> <p>Our research indicates that distance to viable seed sources may be the key mechanism that determines post-fire regeneration in dry mixed-conifer forests of the Northern Rockies. However, the majority of the landscape burned by large wildfires is sufficiently close to a live tree edge to successfully naturally regenerate. Furthermore, the mix of species present and the patch diversity of the burn mosaic within mixed-severity fires indicates that dry mixed-conifer forests are highly resilient to current patterns of fire. However, climate change could impact forest resilience in the future if fire frequency or the proportion of area burned severely increase.