By Richard Schiffman
For residents of the Rocky Mountain region of the United States and Canada, global warming is not an abstract concept. It is a reality they confront every day in the form of tens of millions of acres of pine and spruce trees that have died as a result of beetle infestations spawned by a hotter, drier climate.
Few people know as much about this forest plague as University of Montana entomologist Diana Six, who is working with colleagues to understand why the genetics of some individual trees enable them to survive even as whole forests around them are turning brown and perishing. Six says the infestations are now happening worldwide, with major outbreaks in Africa and Europe. But the worst impacts to date are in the North American West, where bark beetles are spreading quickly into new territories and attacking high-altitude tree species that were previously unaffected.
In an interview with Yale Environment 360, Six explains the root causes of the beetle infestations, discusses why U.S. Forest Service policies may be making the problem worse, and describes why the best hope for Western forests will come from the trees’ capacity to genetically adapt to a new climate regime. Science, she says, can help support this natural process of evolution by mapping genetic markers in trees that survive the insects, so forest managers can breed trees that are better able to cope with future beetle onslaughts. “The only way that we can help our forests in the long term is to strengthen their genetic abilities for adaptation,” says Six. “We have to consider some radical new ways of thinking.”
