PIERCE COUNTY, Wash. — Although eastern Washington tends to see more wildfires than the west side, that's something that could be changing. The Department of Natural Resources (DNR) found 40% of the state's wildfires in two of the past three years were on the west side of the Cascade Mountains.
Forests that have been impacted by wildfires begin to regenerate quickly, leaving the forests littered with dead limbs, and new growth, which are vulnerable to catching fire again.
Western Washington fires are what scientists call "stand replacement fires," which means large swaths of trees are killed, although the trunks can stand for years before rotting and toppling over
Forestry tudents from the University of Washington are helping gather data from multiple plots of burned land left over from the Norse Peak fire of September 2017 and comparing them to unburned areas of old-growth forest.
“Part of this research for DNR will help identify those locations where we can rely on natural regeneration, to meet our objectives,” said Josh Halofsky, a research scientist with DNR. “And also to find locations where we may want to go in and assist in some of that replanting to further forest growth and development.”
Just like the east side, fire is part of the ecosystem in western Washington. Even old-growth forests with trees hundreds of years old have likely endured forest fires before. The question is, will climate change spark fires more frequently on the west side of the state?
“As conditions for fire potentially become more and more frequent as the climate warms, we should expect that potential for fire may also increase on the west side,” said Assistant Professor Brian Harvey, of the U.W.’s School of Environmental and Forest Sciences. “So in a system that’s characterized by very long fire intervals, that may mean instead of fires happening say, every 500 years, we may see fires every 250 years or every 100 years.”
Should fires spark more frequently partially depends on a recipe most large west side fires require to get going; dry conditions late in the season, an ignition source, and strong winds out of the east.