Weed & Pest
Pine beetle epidemic enters a new era, managers focus on long term
Wheatland — Pine beetle populations are tapering off in southern Wyoming forests as the pine bark beetles have literally eaten themselves out of house and home.
Director of Renewable Resources on the Medicine Bow National Forest Steve Currey spoke to attendees at the mid-March meeting of the Southeast Wyoming Resource Conservation and Development Council. Between 2007 and 2008 Currey said beetle populations grew by 85 percent. Between 2008 and 2009 the expansion rate slowed to 35 percent.
Across southern Wyoming forests Currey said the beetles have killed 90 percent of trees five inches in diameter and larger. The beetle’s preference is trees less than eight inches in diameter, but limited food supplies have resulted in their attack on smaller trees.
Wyoming and the region’s pine beetle epidemic resulted from what Currey called a “perfect storm.” While pine bark beetles have long been a part of the environment, a series of conditions allowed them to flourish beyond healthy levels. Drought weakened trees are more susceptible.
“Healthier trees can protect themselves by expelling sap and pushing the beetles out,” said Currey. Older trees are also more susceptible and Currey pointed out that fire suppression has resulted in an “older, more dense forest than we’ve historically had.”
The beetle populations are now moving north, with a greater abundance being seen in the Big Horn, the Black Hills, the Shoshone national forests and on into Canada. The Black Hills National Forest, due to a greater abundance of ponderosa pine and a lesser number of lodgepole pine, isn’t as susceptible as some other forests. The beetles have the greatest impact on lodgepole pine.
In southern Wyoming, forest managers are turning their attention from beetle management to forest conditions. “Fire is the biggest concern, especially when the trees still have their needles,” said Currey. There’s also the concern of falling trees, an issue that will become more severe in about five years. “If you thin the stand they come down quicker,” noted Currey. He estimates most of the trees will fall within 12 to 14 years.
The Forest Service is focusing its attention on campgrounds, roadways and other high use areas. “We’re removing the wood within 80 or 90 feet of the road,” said Currey.
The removal comes at a cost of $40,000 per mile. Over the last two years he said the Forest Service has removed 120 million board feet from the forest. “We could do more, but the industry isn’t there to take that wood,” said Currey.
In the case of the sawmill in Saratoga that remains inactive, he said the plant’s owners say they need a million new home starts per year before they can justify reopening the mill’s doors. Increased timber prices and demand, said Currey, would help solve fuels problems in a more economical manner.
With an eye on public safety Currey said, “If the wind is blowing 20 to 30 miles per hour or higher, I wouldn’t go to the woods.”
As the Forest Service looks ahead, they’re hopeful they can keep this cycle from repeating itself. The agency’s plans call for a mosaic of age classes in the years ahead, rather than the dense old growth forests of recent years. Treatments, said Currey, need to result in a variety of age classes rather than the single age class that will replace those trees recently lost to beetles.
“The pendulum has been on the environmental side and it’s swinging more toward center,” said Currey when asked if the environmental movement will allow the transition in management. As the beetle epidemic reaches its end it brings with it a new approach to forest management aimed at preventing a repeat in the cycle.