In 2006, the Tripod Complex Fire burned more than 175,000 acres in north-central Washington. The fire, which was within the Okanogan-Wenatchee National Forest, was more than three times the size of Seattle. Yet while considered severe at the time, even larger wildfires in 2014, 2015 and 2021 have since dwarfed Tripod.
Past research shows that large and severe wildfires like these were much rarer in the western U.S. and Canada prior to the late 20th century.
“Fire exclusion policies for much of the 20th century yielded many dense forests with largely uniform composition,” said Susan Prichard, a research scientist with the UW School of Environmental and Forest Sciences. “By the turn of this century, we had mature and densely treed, multi-layered forests with high fuel content — and as a result, large, destructive wildfires can ignite and spread more easily. There’s simply more to burn across large landscapes.”
Prichard, along with colleagues from the U.S. Forest Service’s Pacific Northwest Research Station — Paul Hessburg, Nicholas Povak and Brion Salter — and consulting fire ecologist Robert Gray, have created a modeling tool that will allow managers and policymakers to imagine and realize a different future: one where large, severe wildfires like Tripod are once again rare events, even under climate change.
The tool, known as REBURN, can simulate large forest landscapes and wildfire dynamics over decades or centuries under different wildfire management strategies. The model can simulate the consequences of extinguishing all wildfires regardless of size, which was done for much of the 20th century, or of allowing certain fires to return to uninhabited areas. REBURN can also simulate conditions where more benign forest landscape dynamics have fully recovered in an area.
Read more at UW News »