Raging wildfires: Climate changes to blame for record season?

The images are stark: soot-grimed firefighters steering bulldozers or wielding shovels to clear underbrush; curtains of orange flame tracing the contours of summits; aircraft dumping chemicals to slow a fire's progress.

Between Jan. 1 and early July of 2011, slightly more than 38,000 wildfires charred the landscape in the United States at a record pace. So far this year, wildfires have consumed just under 4.9 million acres of forest and grassland, a cumulative expanse the size of New Jersey.

That's 1 million more acres than fires consumed during the same period in 2006, which saw a record 9.9 million acres burned for the entire year.

Beyond the numbers, this year's fires may provide the first large-scale tests of the effectiveness of projects undertaken over the past decade to help forests survive wildfires, several specialists say.

The West's forests are adapted to deal with certain types of wildfires, researchers note. But since the mid-1980s, they add, some of these forests have experienced an increasing number of fires to which they are not well adapted.

Many researchers trace this shift in part to climate change. Thus, restoration efforts focus not only on how to reestablish fire regimes that these forests can best endure, but also on how to do this in the face of an already-changing climate.

The alternative: large, intense fires likely to trigger long-term shifts in the makeup of vegetation, with as-yet-unknown effects on ecosystems and watersheds.

"This is the year we will be able to go in and complete the experiment," says Melissa Savage, professor emeritus of geography at the University of California, Los Angeles, and a trustee of the Valles Caldera National Preserve, west of Santa Fe, N.M. "So much acreage burned, and it burned over so many restoration treatments, that we will get the answer this year" regarding which treatments worked, which didn't, and why, she says.

In 2000, for instance, the US began thinning forests where firefighting efforts over the preceding century had allowed smaller trees and shrubs to build up beyond normal levels. Called the National Fire Plan, the program targeted some 42,500 square miles of forest, especially where forests and communities meet.

Those efforts, and others, are indeed undergoing a big test this year. In Georgia, firefighters are battling a 295,000-acre blaze in the Okefenokee National Wildlife Refuge. The fire began April 30. And Texas, which begins its tally each Nov. 15, has seen nearly 14,000 fires burn a record 3.2 million acres so far this season.

Meanwhile, firefighters in New Mexico are struggling to contain the Las Conchas fire, which began June 26 and has burned nearly 148,000 acres. In Arizona, the Wallow fire is more than 95 percent contained. That blaze began May 29 and has blackened 538,000 acres, including 15,000 acres in New Mexico. Both fires set state records.

The number of acres burned in 2011 could surpass the record set by wildfires in 2006, says Roberta D'Amico, an information specialist with the National Interagency Fire Center in Boise, Idaho. But, she cautions, much will depend on what happens in other parts of the West in July and August.

Although heavy snows this past winter as well as spring snow and rain in the Northwest and northern Rocky Mountains have triggered flooding along rivers, they also have kept forests moist, reducing the risk of large, intense wildfires.

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