Yellowstone National Park's 1988 fires were not a devastating disaster, but an inevitable step in the forests' rebirth, according to an expert from the park.

"My feeling is the fires are a resource in and of themselves," Jim Sweaney, resource management coordinator for Yellowstone's North District, said in a Deseret News interview. "We can put fires off by put-ting them out, but they're inevitable."Sweaney spoke this week at Highland High School, in a free lecture sponsored by the Utah Wilderness Association.

He has a quick answer for anyone who wants to know what Yellowstone will look like after the great blazes. "Remember what it looked like before the fires, because that was also post-fire."

What happened last year was simply part of nature's great cycle of forest fires and rebirth, the woods' maturity and old age - rhythms that must have been rejuvenating forests since the days of the dinosaurs.

Vegetation in the northern Rocky Mountains, particularly Yellowstone, has not only evolved ways to survive fire but actually uses fire to perpetuate itself.

"For instance, lodgepole pine uses it against encroaching spruce and fir forests," he said.

"Lodgepole pine cannot reproduce in its own shade or in the shade of other forests," he said. But competing species, like Englemann spruce, can grow in the shade. So the spruce may threaten to overtake and crowd out the lodgepoles.

But the lodgepole pines leave a great buildup of dry litter - for example, branches and needles, fallen trunks that die because of beetles. This is extremely combustible litter. In fact, Sweaney said it is designed to burn easily.

When enough litter has accumulated, forest fires start.

"A fire will generally kill all the adult lodgepoles as well as all the adult spruce and fir," Sweaney said. "But the lodgepole has cones that are sealed shut by resin, which is melted by the fire."

The resin melts, the cones open, and the seeds are released from the cones.

"After the fire it can seed in lodgepoles so thick and fast that it will beat the spruce-fir forest or any other vegetation that's competing with the lodgepole plants."

This is happening in the burned-over sections in Yellowstone, which amount to just under 1 million acres of the park's 2.2 million acres.

"We found from 50,000 to over a million lodgepole seeds per acre," he said. "People see that the park has been burned up. But what's really happened is that it's replanted itself."

Except for a very few animal species that prefer old-growth forests - like red-backed voles, red squirrels and great gray owls - other animals benefit from the fires, he said.

"Fires are every bit as much a part of the park as rain is," Sweaney said.