UW students explore uses for beetle-killed trees

Wyoming recently reached 1-million acres of forest affected by bark beetles, while Colorado forests approach 2 million acres, according to the US Forest Service Bark Beetle Incident Management Team.

Last fall semester, University of Wyoming students in the Environment and Natural Resources Program’s “Capstone” class studied the bark beetle issues in their research writing an Environmental Assessment. The idea of harvesting beetle—killed trees in the Medicine Bow National Forest and converting the dead trees into biofuel often led to more questions than answers.

But much of the discussion centered on how to turn this environmental issue into a positive outcome for the environment.

Climate change and warmer temperatures can lead to fewer days of low winter temperatures, which in turn can increase the survivability rates of beetle larvae. This has contributed to the bark beetle crisis growing to such epidemic levels that many fear leaving behind the dead timber can also exacerbate the issue. This is because these normally healthy green forests serve as carbon stores and carbon dioxide sinks.

Forests store large amounts of carbon in the trees and soil. They accumulate more over time as they remove carbon dioxide, the major greenhouse gas, from the air and store the carbon in living trees and other plants. Over time, some of this carbon is emitted back into the air from decaying trees and respiring vegetation.

With all these various pieces to the puzzle, students considered whether beetle kill forests are more susceptible to forest fires that also cause brief but rapid emissions of carbon dioxide, in addition to the more potent greenhouse gases: methane and nitrous oxide. However, students snuffed out this notion.

It is assumed that the large swaths of dead trees are more prone to catastrophic forest fires. But recent studies, including a NASA-funded research project in Yellowstone National Park, have revealed that while green needles on trees appear to be more lush and harder to burn, they contain high levels of very flammable volatile oils. It was noted in the NASA-Yellowstone study that when the needles die, those flammable oils begin to break down. As a result, depending on weather conditions, dead needles may not be more likely to catch and sustain a severe crown fire than live needles.

Students also considered the broader, more global implications. They discussed biomass projects, such as turning beetle killed trees into biofuel as potentially helping the global effort to curb greenhouse gasses.

Biofuel production uses organic materials to produce fuel for use in transportation vehicles of all kinds, including cars and planes. The capstone class evaluated the biofuel in the context of providing a fuel source for the University of Wyoming steam plant as an alternative to coal.

While it is not exactly like turning lemons into lemonade, companies are making some advances in the technology aimed to transform bark beetle killed trees into motor fuel. For example, a Colorado State University lab is working to test the fuel in a four-stroke Honda engine. A California-based company has turned lodgepole trees into the biofuel butanol, which is more like gasoline than ethanol.

“One of the issues with conducting this process in Wyoming is the lack of mills,” said Les Koch, forest biologist with the Wyoming State Forestry Division. “We have really lost that sector of forestry, with mill closures all over the state, including the one in Laramie.”

Other uses for beetle—killed trees that the capstone class has discussed are for timber and lumber products. While lumber produced for market may not be occurring in Wyoming due to the mill closures, the harvested trees in the state are being utilized in the region for this purpose, Koch said.

Beetle—killed trees on the market are easy to identify with what is left behind, a blue stain on the wood, after the beetles have killed the tree. The blue stain fungus is carried into the tree by special “pouches” on the bark beetle. The fungus then completely clogs up the water nutrient transporting cells in the sapwood, and quickly kills the tree.

“How do you respond to consumers who may be concerned about buying the blue stain lumber from places like Home Depot,” asked Crystal C’Bearing, a student in the course.

Koch said that some lumber has always had blue stain, as bark beetles have always been a part of nature’s cycle, but with the bark beetle impact now reaching epidemic proportions, the industry has experienced a much larger supply of trees with blue stain.

“As far as any stigma to buying blue stained trees, this is really a non issue,” said Koch. “There is no difference in the structure of the wood or the retail price. Once a tree is processed in a mill, it goes through large vats that dry out the material. It is only a live fungi when it is in the ground with roots and a water supply.” he said.

DOWNLOAD an informational brochure on blue-stained wood by the Council of Western State Foresters.

READ more about beetle-kill trees and biofuel in the Denver Post article: “The deaths of lodgepole pine trees have a silver lining.”

VIEW a video of the NASA-Yellowstone forest fire research work.