Environment: The Fires Next Time

"Smokey the Bear has been lying for years."

—Park Biologist Lloyd Loope

Ever since 1945, ranger-hatted Smokey has led the U.S. Forest Service's campaign against the menace of forest fires, urging campers to douse their fires and extinguish matches and cigarettes with the greatest care. Now both the Forest Service and the National Park Service are coming around to the idea that a few naturally caused fires may actually be good for forests.

The shift was partly brought about by the mountain pine beetle, which is destroying lodgepole pines in unprecedented numbers in the Wyoming-Idaho-Montana area that includes Yellowstone National Park (now celebrating its...