Fast Burn.

It's not a figment of Y2K mania: Wildfires in the great Forests and open spaces of the western United States really are getting worse.

For decades, firefighting agencies from the feds on down to local volunteer outfits have aggressively fought back the fires that break out en masse during the summer and autumn months, throwing enough resources behind the battles to make Smokey the Bear breathe easy. While such actions may keep national forests and parks open during tourist season, they also disrupt a natural cleansing cycle. Fires are an integral part of the ecosystem; they enrich and renew the soil and get rid of old and diseased vegetation. Some trees, such as the Lodgepole Pine, can't reproduce without fires.

In a shift of its traditional position, the U.S. Forest Service, which oversees 191 million acres of national forests, now says that quickly snuffing out fires actually increases the danger to national forests in the interior West. In the days before fire-retardant foam and aerial water drops, smaller and more frequent naturally occurring fires would burn unchecked until they ran out of fuel. The ardent fire suppression of the past few decades means that a lot of underbrush, fallen branches, and dead and dying trees; that would otherwise burn away every couple of years haven't done so. So now, when the fires do start, there's a huge amount of highly flammable material lying around. That's a recipe for massive, often catastrophic wildfires, the likes of which have been more common in recent years.

The Forest Service's realization that fire suppression has contributed to fewer but more intense and destructive fires brings the agency more into line hard-core environmentalist thinking, which favors a "let it burn" policy. That's not to say the Forest Service is ceding all control to Mother Nature. The agency is developing a brush-reduction plan for 39 million acres of at-risk forests that would entail setting planned fires known as "controlled burns."

According to recent congressional testimony Barry T. Hill, an official with the U.S. General Accounting Office, the price tag for the plan might run as high as $725 million a year. While such "controlled burns" often have good results, they also present problems of their own: There are the myriad environmental hurdles to consider, including rules about clean air and water. There's also the potential for torching endangered animals. An d contrary to their name, controlled burns aren't all that controllable. Intentionally set blazes often jump their lines, scorching numerous acres of land and homes. This Fourth of July weekend, for instance, a controlled burn in California ended up burning 23 houses to the ground.