Vast stands of mountain pine beetle-killed forests make people, including me, nervous. We know from camping and hunting trips that dry wood burns better than wet or green wood. Logically, it would follow that whole mountainsides of dead and dry forests will burn fiercely. All it needs is a lightning strike or a carelessly flicked cigarette to start conflagrations of biblical proportions.
   

   Nervous, heck. That’s downright horrifying. 
  

   Wyoming and much of the West is dealing with an unprecedented explosion of tree-killing insects, ranging from the spruce bud worm to varieties of bark beetles that attack several species of pine. Thanks to milder winters (can you say global warming?), these bugs aren’t getting slapped down by bitterly cold winters where 20-below temperatures kill insects and eggs tucked beneath insulating bark.

 

The absence of killer temperatures has meant an explosion of bugs that have always been part of forest ecology. They’ve periodically swarmed out and killed lots of trees, then declined to remnant populations under the impact of severe winters. Not in living memory or historical record have we seen such an outbreak of tree-killing bugs, and consequently, such vast areas of dead trees.

   

   Just last month, state and federal forestry officials held a press conference under the capitol rotunda in Cheyenne, to describe the alarming spread of this insect infestation. 
   

   A 2007 aerial survey showed that the infestation in southern Wyoming had grown 138 percent since 2006. Indeed, state and federal forestry officials are predicting that unless a bitterly frigid cold snap comes along, Wyoming’s mature lodge pole pines are doomed within five years.
   

   Wyoming Governor Dave Freudenthal took note of all this in a press conference last month, when he bemoaned the situation and the fact that there’s little to be done. Several Wyoming saw mills have closed due to poor market conditions, he said, and a flood of timber imports from Canada.
   

   “The lumber market has tanked,” he said, so there’s little prospect that the timber industry can do much to help - not with an 18-month window to harvest beetle-killed trees before they lose commercial value. The governor also complained that the Forest Service’s firefighting budget is getting cut.
   

   All Freudenthal sees is the prospect of ever more disastrous wildfires, and as dead timber falls down into piles on the ground, intensely hot fires that will sterilize the soil.
   

   It sounds like a disaster movie.
   

   But is it?
   

   Maybe not, according to researchers in Yellowstone National Park and the University of Wyoming.
   

   Remember those spectacular wildfires in Yellowstone in ’88? Roy Renkin does. He’s a vegetation management specialist for Yellowstone, and prior to the ’88 fires, he’d been exhaustively mapping earlier beetle-killed forest stands going back to the 1960s.
   

   What he and some Harvard researchers found in the wake of the ’88 fires was counter-intuitive. Statistically, beetle-killed areas of the Yellowstone forests had only an 11 percent higher risk of burning than forest areas with no beetle-kill.
In fact, a beetle-killed forest from 1980 showed zero increase in risk of burning, said Renkin, in spite of a wild fire season and hot embers blown all over the park.
   

   Curiously, when Renkin and his associates analyzed the data and maps, there was a spike in wildfire risk for beetle-killed stands that had been there for 15 years. 
   

   What’s so special about 15 years?
   

   According to Renkin, that’s about how long it takes in Yellowstone for the forest canopy to open up and for sunlight to trigger growth in the once-shady understory. That’s enough time and energy to grow a set of grasses, shrubs and young trees, to create ladder fuels that would carry flames up into the crowns of dead trees. And it takes a crown fire to really get a wildfire rolling.
   

   As for the specter of sterilized soils, Renkin doesn’t sound too worried. Sterilized soil doesn’t happen that often or go that deep. “Sterilized soils are highly desirable for seeds – they make great germination beds,” he said.

   

   Take the 1983 blowdown of trees between Canyon and Norris, he said. When the ’88 fires rolled through, all that downed timber burned hot enough to convert the top eight-to-twelve inches of soil into ash. Twenty years later, a lush stand of 18-foot-high trees is there.
   

   UW’s Dan Tinker, an assistant professor of botany, is skeptical of the doom ‘n gloom of conventional wisdom as it pertains to beetle-killed trees and severe wildfires. He doesn’t see the disappearance of lodge pole in five years – not with numerous young trees biding their time in the understory, too small for the beetles.

   

   He agrees this beetle outbreak is unprecedented in recent history, but speculates it could have happened before, during previous warming periods. “Could it have happened in the 13th century? We just don’t know, because the evidence disappears so quickly,” he said.
   

   So maybe, just maybe, the upcoming fire season might not be so bad after all.
   

   But watch out in 15 years.