Pine beetle-killed trees decline in Idaho as insects find fewer good targets

2013-03-05T23:00:00Z Pine beetle-killed trees decline in Idaho as insects find fewer good targetsThe Associated Press The Associated Press
March 05, 2013 11:00 pm  • 

IDAHO FALLS, Idaho (AP) — U.S. Forest Service officials say the number of trees being killed by pine beetle infestation is on the decline, in part because the insects have eaten themselves out of house and home.

The beetles burrow under the bark of pine trees to lay eggs. Once the eggs hatch, the larvae eat the inner layer of bark, killing the tree. An aerial survey in 2010 showed beetle-killed trees on 9.2 million acres of public and private land in Western states, including nearly 2 million acres in Idaho.

The number of infested acres in Idaho has dropped 63 percent in the years since, to about 719,000 acres in 2012.

Experts feel confident the decline will continue.

"[It] is declining for multiple reasons, but the main factor is they've killed most of their suitable hosts," U.S. Forest Service entomologist Carl Jorgensen told the Post Register.

Once a tree is infested, it can't be saved.

"There's nothing we can do for it at that point," said Tom Eckberg, Idaho Department of Lands Forest Health Specialist.

The beetles prefer lodgepole pine, whitebark pine and ponderosa pine. They seek out trees with the thickest layer of phloem — the inner layer that larvae feed on — and that means they typically attack trees that are at least 8 inches or larger in diameter, that are 80 years old or older, and that are growing at an altitude of 6,500 feet or lower.

When adult beetles find a suitable host, they send out a pheromone to signal other beetles to the tree, Eckberg said.

After the tree is full of beetles, another pheromone is sent out telling new insects to find another home, said Sandy Kegley, a Forest Service entomologist.

"They will continue to kill trees until they run out of suitable hosts or very cold weather kills a large portion of beetles," Eckberg said.

Last year's massive wildfires, which burned about 1.7 million acres in Idaho, also may have contributed to a decrease in the acres lost to beetles this year.

"The fires could have killed the trees the beetles would have eaten," Eckberg said. "But that's uncertain."


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(5) Comments

  1. prog
    Report Abuse
    prog - March 06, 2013 3:57 pm
    Hey Sassy et al: I don't disagree that forest management has been inconsistent at best and incompetent at worst, but, the principal reason that the various species of pine beetles have been flourishing in the last decade or so is due to extended droughts that stress trees and reduce their natural ability to repel these insects coupled with the effects of climate change, mainly substantial warming that prevented extended periods of sub-zero temperatures to kill the larvae and encapsulated adults thus allowing them to spread to adjacent trees. Perhaps folks who deny climate change may wish to rethink the lack of effort to prevent these severe changes and place the proper responsibility on those entities that have forestalled effective regulations that could have mitigated the long term effects of rising C02 and the many other greenhouse gas levels that will now impact our lives for the next several hundred years.
  2. Sassy
    Report Abuse
    Sassy - March 06, 2013 3:24 pm
    Prog- the enviro's have hamstrung lumber harvest and that is a fact. If the forests could be managed through harvest, we would not have the this bug problem or least not as bad another fact-- Don't fall out of the tree....
  3. brianvmax
    Report Abuse
    brianvmax - March 06, 2013 12:33 pm
    there is no arguing the fact that there has been no managment of our forests for years, letting grow to burn or be infested is not managment, it is a renewable resource and should be treated as such, do you remember when watt lost his job for saying the fire in yellowstone should be allowed to burn, now they ooh and aah at how great the fire was for the forest. things that make you go hmmm
  4. prog
    Report Abuse
    prog - March 06, 2013 9:39 am
    Hey Sassy: with the paucity of knowledge you just demonstrated I'm surprised you have time to read a paper at all what with all that Fox News programming where they seldom report accurately and hence make it impossible for anyone to make an informed decision.
  5. Sassy
    Report Abuse
    Sassy - March 06, 2013 6:21 am
    Yikes the beetle is running out food- Thank you Enviro's for creating this problem
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