This undated aerial photo provided by the U.S. Forest Service
shows pine trees killed by beetles near Granby, CO. Is manmade
climate change the culprit for the pine beetle epidemic?
(AP File Photo)
A tiny little bug about the size of a grain of rice has become a focal point in the debate about manmade climate change. Over the last 12 years, the mountain pine beetle has spread quickly through the Mountain West and Canada killing millions of acres of pine trees.
The beetle thrives when conditions are drier and warmer than average and some experts have blamed its spread on manmade climate change and a warming environment. From Canada south to Colorado, images of acres of dead, brown trees amongst their healthy neighbors make for a stark picture of what may be forests in decline.
Global warming activists have been quick to seize on the pine beetle ‘epidemic’ as a sign of things to come and an impending ecological disaster. In truth, drawing the line between manmade climate change and the pine beetle outbreak is a stretch that few experts make. Rather, most see the outbreak as a natural function of forests and in many ways it is Mother Nature correcting man’s previous mistakes.
A mountain pine beetle is seen on the tip of forester Cal
Wettstein's knife. He was checking trees near Vail, CO.
(Ed Andrieski / AP)
Colorado finds itself front and center in the battle against the mountain pine beetle. In the coming weeks the state’s forest service will be releasing its annual report and is expected to estimate that 2.5 million acres have been infected by the beetles since 1996 – the largest outbreak in state history. However, that represents a fraction of the state’s forest land and areas are being naturally rehabilitated after the infections pass.
The state’s forest service is reluctant to connect manmade climate change with the outbreak and studies have shown that while the outbreak is large, it is not entirely unprecedented. Sky Stephens, Forest Entomologist for the Colorado State Forest Service, says that while climate change is a hot topic, there "hasn’t been a well structured argument” connecting the two.
Indeed, the state points to what it calls a ‘perfect storm’ of drought, recent warmer winters and forests that are denser than what nature intended. Any one of those factors could lead to an increase in beetle populations but coupled together, it becomes a difficult situation for foresters to manage.
Man may indeed have played a large role in the spread of the mountain pine beetle but not in the way climate change activists portray.
Man may be partially responsible for the spread of the mountain
pine beetle but it is more likely due to his attempt to “save” the
forest from forest fires in the 20th century than it is global
warming. (Jae C. Hong / AP Photo)
For the latter half of the 20th century as people settled in forested areas in greater numbers, forest fires drew more attention. While in centuries past fires burned unabated as part of a natural cycle of the earth, man now was coming to the “rescue” and putting out the fires. In doing so, an unintended consequence of forest overgrowth was realized. By eliminating the natural death and re-birth cycle that fire brings, forests became more dense and just as critically, they have matured to an age that is ripe for pine beetles to attack.
Stephens said that our desire to stamp out fires in unpopulated areas did more harm than good. “It set us up for a number events that have and are going to happen,” she said. Stephens said the forests were never meant to have the dense stands that we have grown accustomed to seeing and the more food there is for the beetles, the greater the impact when they attack.
Dave Thom, a natural resources officer with the Black Hills National Forest agrees with Stephens. Of trying to point the finger at manmade climate change, he told the Rapid City Journal last month, “It’s more complicated than that.”
That phenomenon [the pine beetle epidemic] can happen regardless of a few degrees of change in climate, measured on a global scale.
~ Dave Thom, Black Hills National Forest
The drought and the dense forests play a big factor according to Thom. He said, "As the trees get more dense, they are less able to resist bark-beetle infestations. When you take increasingly dense trees and add the drought, the intersection causes weakened trees that are more susceptible to beetle attack. That phenomenon can happen regardless of a few degrees of change in climate, measured on a global scale."
Researchers point to beetle outbreaks in the past that killed millions of pine trees, before the theorized human-induced temperature rises of the late 20th century. The Rocky Mountains suffered through outbreaks in the 1960s, the 1970s and the early 1980s. A different beetle, the spruce beetle, is known to have caused extensive damage in western Colorado in the 1940s.
There is no evidence to support the idea that current levels of bark beetle or defoliator activity are unnaturally high.
~ Colorado Forest Restoration Institute
A recent study completed by the Colorado Forest Restoration Institute (CFRI) in conjunction with the Colorado State Forest Service and area universities flatly stated that the current outbreak is not unusual. “There is no evidence to support the idea that current levels of bark beetle or defoliator activity in Colorado’s lodgepole pine and spruce-fir forests are unnaturally high,” the study said.
Before outbreaks were documented, tree-ring evidence points to extensive outbreaks before the 20th century as well. As the CFRI study said, “Insect outbreaks are a natural occurrence in almost all of the different kinds of forests in Colorado. Outbreaks do not occur very frequently; the time interval between successive outbreaks in any given area is usually measured in decades. Nevertheless, outbreaks can be expected periodically in almost any place in the state where forests are found.”
CFRI as well pointed to the age of the current forest as a factor in the outbreak. “Widespread burning in the late 1800s that resulted in extensive cohorts of relatively similar age that now are entering a stage that is susceptible to bark beetle outbreaks,” the study said.
The ravages of the mountain pine beetle are evidenced by anyone that travels in the Rocky Mountains. The damage occurs over a short period of time and can encompass large areas thus making the outbreaks seem unusual.
However, the reality appears to be that the pine beetle, much like fire, is simply a natural process forests go through. And while the current outbreak is larger than we remember, Stephens summed it up by saying, “The beetles haven’t read the textbooks.”
Image courtesy Colorado State University