Summer fire seasons in the great forests of the West have always hinged on elements of chance: a heat wave in August, a random lightning strike, a passing storm front that whips a small fire into an inferno or dampens it with cooling rain.
But tiny bark beetles, munching and killing pine trees by the millions from Colorado to Canada, are now increasingly adding their own new dynamic. As the height of summer fire season approaches, more than seven million acres of forest in the United States have been declared all but dead, throwing a swath of land bigger than Massachusetts into a kind of fire-cycle purgatory that forestry officials admit they do not yet have a good handle on for fire prediction or assessment.
Dead trees, depending on how recently they died, may be much more flammable than living trees, or slightly more flammable, or even for a certain period less flammable. The only certainties are that dead forests are growing in size and scale 22 million more acres are expected to die over the next 15 years and that foresters, like the fire-tower lookouts of old, are keeping their eyes peeled and their fingers crossed.
Theres just a lot more fuel in those dead forests available to burn, said Bob Harrington, the Montana state forester, who is focusing additional resources this summer on a three-million-acre zone of beetle-infested forest from Butte to Helena.
More than 100,000 people live in that area, and Mr. Harrington said that although fire forecasts for Montana, as in most of the West, called for only an average fire season, dead forests do not play by the rules. They can dry out much faster in heat, without living tree tissue to hold water.
Other beetle watchers say the nightmare of a severe fire season concentrated in the dead-forest zone running along the spine of the Rocky Mountains has, so far, been averted. In Colorado, a combination of deep snows last winter followed by a wet spring has kept fire danger low. But scientists say that recent winters have also lacked the stretches of deep cold 20 to 40 degrees below zero that can check the insects spread.
Right now, in our neck of the woods, were really wet, said Mary Ann Chambers, a spokeswoman for the federalForest Services bark beetle incident management team for afive-state region that includes Colorado. We seem to have dodged the bullet again.
The governments four-month fireforecast issued in June called for a potentially more active fire season in central Washington and Northern California. But most of the rest of the region, like the country, is expecting normal or below-normal conditions.
Budgets for firefighting and prevention, increasingly important as more people move closer to the edge of the public lands, are in flux in the fire zones, forestry experts say. Millions of dollars in federal economicstimulus money is flowing toward tree-thinning for fuel reduction in and around communities like Ruidoso, N.M., and Anchorage. But many states budgets for fire protection are being battered and squeezed by the recession.
Theres a potential for substantial reductions in capacity in many states, said Dan Smith, the fire director for the National Association of State Foresters. Fire prevention tactics are also being reassessed.
A study published this month in TheProceedings of the National Academy of Sciences showed that federal land-management agencies, from 2004 through the end of last year, had mostly failed to reduce fire fuels near communities that are in or next to wildland forests a critical zone of high fire risk called the wildland-urban interface.
The study said that 70 percent of that forest-fringe land was now privately owned in the 11 states west of the Plains States (not counting Alaska or Hawaii), and that partly because of ownership difficulties, only 11 percent of the fire mitigation work had occurred in the places it was needed most.
Tania Schoennagel, a research scientist at theUniversity of Colorado, Boulder, and the studys chief author, said private ownership of some of the wildland-urban interface areas made it difficult to treat those lands and was a vexing problem for federal fire managers.
Theyre between a rock and a hard place, Dr. Schoennagel said.
Meanwhile, the beetles munch on.
The Forest Service proposed a tree-thinning program of fire protection just outside Helena, for example, in 1997, when the forest was green and healthy. The project was stalled by litigation for 12 years until earlier this year, when a federal appeals court in San Francisco finallyruled for the Forest Service that the thinning plan could proceed.
In the interim, the bark beetle entered the picture, said Duane Harp, a district ranger in the Helena National Forest. Now 90 percent of the trees when we started the project are dead.
Government lawyers said the Forest Service could be sued again if it went ahead with the old plan on a now fundamentally altered forest, Mr. Harp said, so foresters are reassessing the impact of thinning in a dead forest.
A technological race to catch up with the beetles and their impact on fire risk is also under way. A forest-health mapping system that will account for the depredations of insects is being developed by the Forest Service and theInterior Department. Called Landfire, the program is expected to be ready by late next year, in time for the 2011 fire season, managers say.
Using satellite assessment and on-the-ground reports, the system will try to give fire managers and forecasters a sense of vegetation stress or health in fire zones across the country, peering into the secret lives of moths, wood borers, beetles and defoliators of every stripe.