Bark Beetles Kills Millions of Acres from New Mexico to British Columbia
The Bark Beetle, or Pine Beetle, from New Mexico to British Columbia, is destroying forests faster than people can even attempt to save them. Green forests are turning to red as trees die and the beetles move on.
In Montana about a million acres has been lost so far, and in northern Colorado and southern Wyoming even more has been lost to a bettle that is no bigger than a grain of rice. In these areas it is expected to reach over 2 million acres of dead trees. This is happening in a much larger and more serious way than I think any of us realize.
In British Columbia and Alberta, it is the largest most severe insect infestation in history, as 33 million acres has been lost.
Foresters say the historic outbreak has several causes. Because fires have been suppressed for so long, all forests are roughly the same age, and the trees are big enough to be susceptible to beetles. A decade of drought has weakened the trees. And hard winters have softened, which allows the beetles to flourish and expand their range.
Hoping to keep their forests from completely dying, to earn money by selling dead and infected trees and to mitigate fire risks, landowners are scrambling to cut the pines. If enough are cut — up to 75 percent — it might leave some behind that, with less competition for water, can survive. Still, for many landowners, cutting most of the forest where they have they built their homes is painful. “I’ve literally had people in my office crying,” said Gary Ellingson, a forestry consultant for Northwest Management.
The black, hard-shelled beetle, the size of a fingertip, drills through pine bark and digs a gallery in the wood where it lays its eggs. When the larvae hatch under the bark, they eat the sweet, rich cambium layer that provides nutrients to the tree. They also inject a fungus to stop the tree from moving sap, which could drown the larvae. That fungus stains the wood blue.
“The Latin name is Dendroctunus, which means tree killer,” said Gregg DeNitto, a Forest Service entomologist in Missoula, Mont. “They are very effective.”
When a beetle gets to a tree and sees that it is able to be attacked, it sends out a call to the others and beetles swarm the tree.
There are measures an owner can take; such as 'aggregator pheromones' which sends out the same chemical scent given off by beetles when calling for reinforcements, but if the beetles are too many in number they will still swarm the tree anyway.
The trees can be sprayed, but they have to be thoroughly sprayed with insecticides, and it can get really expensive.
In 2003 in Southern California, the beetles killed off so many trees and they were so dry that they provided a catastrophic amount of fuel for the devastating forest fires that year.
There are now over 20 species of bark beetles, partly due to the warmer winters as the beetles are not being killed off in the cold weather. The increasingly warmer summers too help the beetle to reproduce more quickly. Many experts agree that the trigger for the infestation has been the change in the weather; a possible side effect of climate change everywhere.