Date of this Version
Fire Science Brief, Issue 72, October 2009
Prescribed burning is now a routine technique used in forests. In some cases, these forests have not experienced fi re for decades. Sometimes, prescribed fire can lead to unexpected consequences. In Crater Lake National Park, prescribed burning to restore the mixed conifer forest there began in the late 1970s with unexpected consequences. Eventually researchers, including Jim Agee, determined that bark beetles were inflicting tree damage, and death. Agee’s doctoral student, Dan Perrakis, focused his entire dissertation on trying to understand much more about the connections between fi re, trees, and bark beetles. With Agee, he did a host of interdisciplinary experiments. He found that at Crater Lake resin flow does not protect trees from beetles. It may be that beetles use resin volatiles released by fire-exposed trees, to home in on weakened trees. Says Perrakis, “The major take home point with this is that the beetles and trees are engaged in an evolutionary arms race,” Perrakis says. “But at Crater Lake, for now, the beetles are winning.” With this, there may be emerging guidance on how managers and planners can better protect forests from the ravages of bark beetles.