PNAS Early Edition has released a new paper last week, authored by several Novus Participants, analyzing fire regimes in boreal forests throughout the last 10,000 years. The study, spearheaded by lead author Ryan Kelly (University of Illinois, Urbana) and co-authored by Novus Steering Committee member Philip Higuera (University of Idaho), analyzed charcoal and pollen records from 14 lakes in the Yukon Flats of interior Alaska.
These records indicate increased periods of burning under warm and dry conditions such as the Medieval Climate Anomaly (1,000-500 cal yr BP) and recent decades. During the MCA, vegetation feedbacks modulated the severity and frequency of fires, suggesting that vegetation dynamics could stabilize fire regimes in this region. Recent decades have seen extreme fire severity and biomass burning, surpassing the previous maximum set during the MCA. This unique fire regime could be stabilized by vegetation feedbacks similar to those during the MCA, despite additional warming in coming years. The ecological and socio-economic importance of boreal forests underscores the importance of understanding long-term trajectories of fire regimes and associated feedbacks in response to climate change.