The study, conducted by the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder and the U.S. Forest Service's Rocky Mountain Research Station, compares fire activity from 1984 to 2022 with data spanning 1600 to 1880. Using 1,850 tree-ring records from historically burned regions, researchers assessed past fire patterns and juxtaposed them with modern fire perimeter maps across the United States and Canada.
Results indicate that despite recent extreme fire years-such as 2020-the overall occurrence of wildfires remains significantly lower than in previous centuries. Data show that much of North America experiences only about 20% of the fire activity observed before 1880. In earlier centuries, larger portions of land burned annually, preventing excessive fuel accumulation. The current deficit, however, has created conditions conducive to more intense and destructive wildfires.
"It's a harbinger for far more bad fires to come unless we can get more beneficial management fires on the landscape," stated Chris Guiterman, a CIRES research scientist and member of NOAA's National Centers for Environmental Information (NCEI) paleoclimate team.
While historical wildfires covered vast areas, they were often less destructive. Surviving trees recorded the burn events in their growth rings, indicating that these fires typically cleared out underbrush while leaving mature forests largely intact. By contrast, modern wildfires, fueled by accumulated debris and dense tree stands, often lead to widespread forest mortality.
The study highlights how shifts in human interaction with fire have significantly altered wildfire dynamics. Prior to 1880, Indigenous fire management practices and naturally ignited wildfires played an essential role in shaping resilient forest ecosystems. These frequent, low-severity burns reduced fuel loads and helped maintain ecological balance.
However, the disruption of Indigenous burning practices, along with the introduction of widespread livestock grazing and aggressive fire suppression policies, has resulted in an unnatural build-up of combustible material. As a consequence, contemporary wildfires burn with much greater intensity, posing greater threats to communities and transforming forests into less fire-resistant landscapes, such as shrublands.
The findings complement other recent studies that suggest historical wildfires, though widespread, were generally less severe and often coincided with regional droughts. Researchers emphasize the importance of proactive fire management strategies to mitigate escalating wildfire threats.
"It's heartbreaking to witness how recent wildfires are devastating people, communities, and forests," said Sean Parks, research scientist with the U.S. Forest Service Rocky Mountain Research Station and lead author of the study. "Wildfires are inevitable, so preparing our forests for these events through fuel reduction treatments and prescribed fire will reduce their impacts to communities and forests."
Scientists advocate for methods such as mechanical fuel treatments and controlled burns to restore a more natural fire cycle. These approaches align with Indigenous fire stewardship traditions and long-standing ecological processes that have historically helped sustain North American forests.
Research Report:A fire deficit persists across diverse North American forests despite recent increases in area burned
Related Links
NOAA's National Centers for Environmental Information (NCEI) paleoclimate team.
Forest and Wild Fires - News, Science and Technology
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