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Meet the beetles! They're killing our trees

December 3, 2010

Dead, red trees on June Mountain. Photo/Forest Service

They’re here.

Bug-eyed and pincher-toothed, no bigger than a grain of rice, the mountain pine bark beetle has come to visit, killing thousands of acres of lodgepole and whitebark pine in our own backyard, turning green mountainsides tomato-soup red.

Though nowhere near the problem they are in the Rocky Mountains, where the beetle has turned huge swathes of green forests to dead, red trees, and where tourism-and ski-resort based economies are reeling from the cost of cleanup and prevention of the red tide, Eastside beetle populations are growing and growing fast.

June Mountain Ski Area is the most obvious and visible example, but drive south toward Mammoth and look toward the San Joaquin Ridge.

Then look up at the Sherwins, and check out the stands of red, dead trees standing on the steep slopes below the Mammoth Crest. Drive up Rock Creek and look south toward the Wheeler Crest or look up Bishop Creek, or Hilton Creek.

All these areas were almost entirely beetle-free just 10 years ago.

Today, the story is very different.

“We are seeing as much as 90 percent mortality of the mature whitebark pines in places like the saddle above Hilton Creek,” said Beverly Bulaon, U. S. Department of Agricultures entomologist for the Eastside.
“The areas are isolated, but it can be pretty devastating especially if they are visible, like they are from June Mountain,” she said.

Although the argument is often that the beetle outbreaks are a natural phenomenon, Bulaon says the infestation in the Rockies is truly “unprecedented,” something historical records show has never occurred before, perhaps due to a combination of climate and other factors, she said.

Although the Eastside has some protection against the beetles that the Rockies do not have, due to the fact that California’s pine forests are more diverse than the forests of the Rockies where one species of pine covers most of the forest (the beetles tend to only go for one species at a time), the nature of the beetle infestations across the country also mean now is not the time to relax and ignore the beetle problem, she said.

June Mountain Ski Area is just one of most obvious examples of the impact a bunch of the tiny, voracious insects can have locally, she said.

Some 10 percent of the ski area permit area has lost most of its whitebark and lodgepole tree cover, since 2007 and the affected acreage has increased each year.

The dead and dying trees are not only aesthetically less pleasing to look at than green living trees to most people, they present a host of problems for the ski area, ranging from the cost of cutting down hazardous trees to worries about what to do if the beetles simply refuse to move on.

“Sure, we’re concerned,” said June General Manager Carl Williams. “We first noticed the trees dying several years ago, but didn’t know what was causing the mortality. Then about three years ago, it really started to become obvious and it seems like since then, it’s just exploded.”

He’s waiting for the Inyo National Forest to release a draft of a vegetation management plan for the ski area, scheduled for sometime this month, according to forest service officials. After that, he will have a better idea of the steps the ski area will be able to take, he said.

Until that time, his options are limited.

“We’re removing hazard trees of course, to make sure the area is safe,” he said. “But we are surrounded by wilderness, which means removing trees outside our boundary by mechanical means is not an option.”
Bulaon said that the rate of spread on June Mountain has slowed minimally this past year, after several years of sharp growth, but that it is far too soon to say if this is a trend or just a blip.

“About all we are accurate with here is forecasting one year out,” she said. “There are just too many factors, like weather and soil and precipitation that can affect the spread of the beetle that we cannot predict far in advance.”

The bottom line is the ski area is now facing something its counterparts in the Colorado Rocky Mountain resorts have had to deal with for years; the increased cost of doing business in a ski area hit by mountain pine bark beetles.

The issue is that the closer the trees are together, the easier it is to spread, since the beetles can only fly a limited distance. Thus, thinning a stand of trees can help prevent the beetles from spreading, although it is far from 100 percent effective.

It is also very, very expensive, given that each must be cut down by a person and a chainsaw. Other options being used are also expensive, such as releasing pheromones that “tell” the beetle to stay away, Bulaon said.

The bottom line is no one anywhere has yet come up with an inexpensive way to either treat or prevent large-scale beetle infestations, she said.

“It all comes down to what your objective is,” she said. “Is it to protect public safety? To protect a viewshed? A ski area? Each one of these objectives will have a different management plan, with different costs.”

With no end in sight, it’s a problem Eastside land managers and locals are likely be dealing with for a very long time to come.

BEETLE FACTS

Mountain pine bark beetles spread from infected tree to infected tree, flying on short stubby wings to each tree, where they bore into the tree and lay their eggs beneath the bark layer.

The more beetles that hit a tree and lay their eggs just under the bark, the less likely the tree is to survive, since it is the layer under the bark, the cambium, that carries nutrients and water from root to branch and back again.

Too many beetles “girdles” the tree, effectively killing it.

Beetles can be killed by extremely cold temperatures, say minus 30 degrees, that persist over several weeks. Many scientists are beginning to believe the rising global temperatures are one of the reasons the beetle has spread, since winters are warming and more beetles survive and go on to reproduce.

Another reason the beetles might have increased to such “unprecedented” numbers is because of the forest fire suppression policy that has dominated land management decisions for a century. Fewer fires mean thick stands of chockablock trees, with a lot of old and weak trees, a bonanza for the beetles that attack the weakest trees first.

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