Tucked behind a red-painted produce stand and rows of potatoes and onions on a Springhill Road farm north of Albany, two researchers who used to work on combustion in jet engines are lighting trees on fire.
They watch as embers float down onto white fabric squares arranged in concentric semicircles around each tree, collecting data that could someday save the lives of wildland firefighters and residents downwind from a raging forest fire.
David Blunck, an associate professor of mechanical engineering Oregon State University, has created a research lab on his farm, where he and postdoctoral scholar Sampath Adusumilli are studying how burning trees behave.
Their ultimate goal is to better understand the amount of hot embers different types of trees release so they can give landowners advice on what species to plant in fire-prone areas.
The project is paid for by funding from the National Institute of Standards and Technology.
Blunck, who previously studied the combustion chambers of gas turbine engines for the U.S. Air Force, said he has continued that work at OSU but now has branched out into wildfire research.
Adusumilli received his doctorate in aerospace engineering from Georgia Tech in Atlanta.
“The science is similar because we both studied the science of fire,” Adusumilli said. “My Ph. D. work was on propagation of flames for aircraft engines. Here I’m applying similar knowledge to propagation of flames to wildfire.”
The current crop of trees they are using are 40 ponderosa pines, ranging from 12 to 20 feet tall, that were harvested during thinning operations in one of OSU's research forests. Earlier this month they experimented with Douglas firs.
Each tree is weighed, placed in a cinder block stand and surrounded by straw, which is also weighed before being placed around the tree. More than 60 stations of fire-retardant fabric are lined up in five semicirclular rows on the south side of the tree.
Once the straw is lit, it is only a matter of a minute or two before the tree catches on fire. Sometimes the entire tree burns up; other times it's just a few branches.
“One of the issues in the forest fire world is that we don’t know a lot about embers.” Blunck said. “And specifically we don’t know for a particular tree how many embers it will release.”
Blunck's original plan was to conduct the burns in a research forest, but when those plans fell through, he decided to carve out a research lab on his farm.
Burning a handful of trees a day, the process takes several days to complete.
On Wednesday afternoon, Blunck works with Adusumilli while Blunck’s children and friends gather around a lookout platform to watch the process. Although the pine tree’s lower branches light, the fire does not extend to the crown.
“What I have observed is this isn’t a scientific analysis,” Adusumilli said in comparing pines to the firs they worked with earlier. “The Douglas fir torched a lot more, whereas with the pine tree, whole tree burning is much more difficult to achieve. But the pine trees could be generating a higher number of embers for smaller mass loss.”
The next morning Adusumilli was running more tests. This time he was working with OSU graduate student Nate Gardner. Before lighting the trees, Adusumilli tossed straw into the air to check the wind direction. The researchers also have an anemometer mounted to the north of the tree for readings throughout the research.
They monitor the wind variations throughout the tests. “We will see how much the wind affected (the results),” said Adusumilli. “We can make some conclusions.”
“Our main goal is to distinguish between total number of embers and the embers that would cause a fire,” Adusumilli said.
At the end of the two-year project, the researchers hope their statistics could be used to help with decision-making in both tree planting and forest fire management.
“If we can have a high certainty on how a forest fire would propagate,” Adusumilli said, “we would be able to save a lot more lives and property.”
Future research will focus on plants such as sagebrush and chaparral, Blunck said.
The team’s research will stop when the seasonal burn ban goes into effect. They will be back at work on Blunck's farm in the fall, when the ban is lifted.
“As long as my wife is happy, we are in good shape,” Blunck said about using their property for the continuing research.
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