Yellowstone National Park has made a remarkably swift recovery from the devastating fires that swept through it in 1988, according to the most detailed study yet done on the fires' aftermath.

The fires, which blackened nearly 800,000 acres, or about 36 percent of the park, raised concerns that one of the nation's most treasured wild places might have been permanently damaged. The fires also prompted sharp criticism of the park service's policy to allow naturally occurring fires to burn.Now, however, wildflowers, lodgepole pines and aspen seedlings are flourishing on the fire-scarred soil, suggesting that the park's recovery is well under way.

"The whole Yellowstone system responded very rapidly," said William Romme of Fort Lewis College in Durango, Colo. "Even in areas where all the plant cover was burned off, within a couple of years there was fairly good plant cover." Large-scale fires do not seem to be a threat to the park, he said.

The studies also have implications for the fires that are sweeping through Western forests this year, Romme said. Firefighters should focus on protection of life and property, he said, because wild lands are likely to recover fairly quickly even if they are severely burned.

"Fire is a problem - not a major threat - to the wild land areas," he said.

Cheryl Matthews, a spokeswoman for the National Park Service in Yellowstone, said Tuesday that she wasn't surprised by the findings. "The year after the fires was one of our best years for wildflowers," she said. Park managers shared the attitude that the fires were "part of the natural process in a national park," she said.