Researchers are working to better understand how large wildfires behave on the landscape.
Wildfires last year in Oregon scorched 1,402 square miles — an area larger than Gilliam County — at a cost exceeding a half-billion dollars. The Northwest Interagency Coordination Center also reported people started 1,330 fires in Oregon that blackened 515 square miles and lightning started the other 689 wildfires, which burned across 887 square miles.
Oregon’s total number of wildfires dropped to 2,019 from the 2,049 in 2017, but wildfires that year burned a little more than 1,1167 square miles.
The 1,743 wildfires in 2018 in Washington charred almost 686 square miles and cost nearly $174 million. The season before, Washington had 1,346 wildfires across a total of 631.6 square miles.
As fires grow in size, the U.S. Department of Defense is funding a four-year, $2.1 million project through the agency’s Strategic Environmental Research Development Program to study the burning of live trees. David Blunck, an assistant professor of mechanical engineering at Oregon State University, was chosen to lead the team.
“Live fuels are basically trees that are green and living,” Blunck said. “These trees are often what torches, but historically, dead fuels have primarily been studied.”
Studying live fuels is a newer area of wildfire research, Blunck said. In the past, research has focused mostly on burning characteristics of a single species at a specific time of year. The challenge for fire managers is predicting how blazes will interact with a new fuel, in terms of ignition and burning.
“We have a finite number of live fuels we’ve tested,” Blunck said. “Do you create a different model for each fuel? If I can create a model that’s predictive over a wide number of live fuels ... that model would be a lot more advantageous.”
To achieve that model, Blunck theorizes that just a handful of processes cause differences in burning behavior when live fuels burn — including temperature and flammable gases given off by different trees. If researchers can understand what those are, they can better predict how new species will burn, Blunck said.
Oregon State University will collaborate with the Forest Service on field work during controlled burns later this year. Laboratory samples will also be analyzed, burning pencil-sized tree limbs and shining lasers to determine which gases are given off.
Blunck is also wrapping up another three-year study looking at how the live trees spread embers when they are engulfed in flames. In recent months, the team has burned more than 100 trees from 10 to 15 feet tall, including Douglas fir, grand fir, western juniper and ponderosa pine.
What they found, Blunck said, was ponderosa pine gave off the fewest total embers, while western juniper gave off the most. That includes hot embers capable of starting new fires.
“Embers are wildfires’ most unpredictable modes of causing spread,” he said. “By understanding how embers form and travel through the air, we can more accurately predict how fire will spread.”
Ultimately, the goal of the research is for firefighting agencies to have better information when fighting fires, and when deciding whether or not to do a controlled burn as part of responsible forest management.
“Ultimately, there is a simulation package that the Forest Service owns. That is a very detailed model, and we’ll be working to update that model,” Blunck said.