Andrew Merschel and colleagues at the Pacific Northwest Research Station and Oregon State University have constructed dozens of new fire histories in the western Cascades of Oregon and Washington. These histories refine our understanding of historical fire regimes in Pacific Northwest rainforests. For the first time, this research pairs direct evidence of historical fires with precisely dated tree establishment data. The novel fire and forest development histories reveal tremendous diversity in the tempo of historical fires and their influence on forest development and conditions.

Contrary to conventional theory, many old trees and forests in the Pacific Northwest were shaped by recurrent low- to moderate-severity fires. Across these landscapes, variation in the number of fires, their timing, and their effects increased diversity in forest successional conditions (e.g., ages) and diversity in tree structure and species composition. Many of the remarkable and beloved features of old forests in the Pacific Northwest including old trees with enormous and complex crowns, multi-layered canopies, and a diverse mixture of tree species developed with fire, not without fire.

In some study locations, exceptionally high fire frequency prior to European colonization is indicative of Indigenous fire stewardship practiced for millennia by Indigenous cultures. This highlights the critical role that Indigenous peoples of the Pacific Northwest had in stewarding and shaping the old trees and forests that contemporary forest management is aiming to restore and conserve. Merschel’s innovative research is sparking a shift in how we think about fires in the Pacific Northwest. Tune in to this webinar to learn some surprising things that we are learning about historical fire regimes and forest dynamics, and how this information might inform restoration of old-growth forests, fire mitigation, and adaptation to a warmer and drier climate.

To learn more and register, visit: https://www.fs.usda.gov/research/pnw/products/multimedia/webinars/hidden-stories-fire-tree-rings-reveal-fire-histories-pacific