Mountain Pine Beetle

Many areas of the Rocky Mountain West have been affected by the mountain pine beetle (Dendroctonus ponderosae) due, in part, to single-age stands and warmer climate. Scientists from the Missoula Fire Sciences Lab investigated changes in foliar chemistry and moisture in affected stands and how they impact fire behavior. 

In laboratory tests, flaming embers were dropped into collected pine needles from beetle-affected trees. Needles with moisture levels in the mid-teens consistently caught fire from a single ember. Additionally, researchers found that the red needles of beetle-attacked trees ignite three times faster than the needles of healthy trees. Both foliar chemistry and needle moisture content were the most important factors in determining a needle’s flammability. This suggests that forests with large number of beetle-killed trees are at a significantly higher risk of burning as actively spreading crown fires.

Crown fires cannot be directly suppressed by ground resources, and are very dangerous to firefighters and communities. This research can help inform fuel treatments in beetle-killed forests, increase firefighter awareness of dangerous situations, and assists managers in identifying areas at high risk for ignition and extreme fire behavior.

Photo Credit

Photo credit: National Incident Management Team (NIMO)

Crownfire burning in beetle-killed timber of the Salt Fire, Sept 2011.

Principal Investigators:
W. Matt Jolly, RMRS 
Russell Parsons, RMRS

Funding Contributor(s):
Joint Fire Science Program
USFS National Forest Systems

Project Years: 2010-2015