Oregon Forest Fire Intensity Can Be Calmed By Thinning: New Study

PORTLAND, OR — With forest fires a seeming permanent and growing threat in the Pacific Northwest and other places, a team of researchers from Oregon State University are studying a variety of techniques to help keep them from becoming monsters that threaten lives and communities.

For years there has been a debate about whether mechanical thinning or prescribed burns are more effective.

The OSU team, led by OSU research associate James Johnston spent months going through years of data. The answer they believe is a combination of the two. First, use a device like a fella-buncher or cut-to-length harvester to think the forest. After that use prescribed burns over a period of years.

"Most of the studies that have been published so far suggest mechanical thinning that isn’t followed by prescribed fire is not as good for moderating fire severity than thinning combined with prescribed fire," Johnston said.

"Some studies have even suggested that thinning without prescribed fire can increase wildfire severity by adding to the buildup of fine fuels on the forest floor."

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OSU says that it was around 130 years that things started to change in how forests were managed, citing "the logging of old fire-resistant trees, unregulated grazing, and a national culture of fire suppression. That led to more forest filled with "fuels" on the ground that would help fires grow.

"Those changes along with a warming climate have led to increasingly large, fast-moving, stand-replacing fires that have significant negative impacts on old-growth habitat, water quality and human infrastructure," Johnston said.

"Consequently a range of non-governmental organizations, tribal, state and local governments and private landowners are trying to adapt by reducing fuels."