The Radio fire of 1977 is unmatched around Flagstaff for its size and proximity to town.

Two other fires north of the San Francisco Peaks had been larger -- the Wild Bill and Burnt fires of 1973, according to Forest Service data. But none had left lasting scars so visible from town.

"Thirty years later, you can look up there and you don't see a big stand of trees coming in just yet," said Dan Neary, a soil scientist at the Rocky Mountain Research Station in Flagstaff.

The fire consumed 4,600 acres on Mount Elden, engulfing radio towers and the communication lines used by dispatchers working the fire.

The blaze started as a teen-ager's small campfire at the southern base of the mountain. Fire crews were building line around the small fire, until the wind slackened.

The fire made a nearly vertical run up Mount Elden in a matter of minutes, where it crossed to the northern and eastern sides and burned for weeks.

An employee occupying a fire lookout tower had 15 minutes to escape, the Coconino National Forest said in a newsletter recounting the events five years ago.

A COUPLE HUNDRED YEARS TO HEAL

Mount Elden is offered by NAU's Ecological Restoration Institute as an example of what happens when a ponderosa pine forest grows 15 times denser than what was typical before pioneer settlement.

With its scrub oak, bare rock and eroded soil, Elden has been compared by scientists at the Rocky Mountain Research Station to a landscape starting over after a volcanic eruption or landslide.

"It's going to slowly heal, but it's going to take a long time. It could be a couple hundred years before it comes back," Neary said.

Regeneration of a full forest can be slowed by soil erosion from the steep slope, lack of seed-donating trees nearby, invasive species, dry winters and thin soils, Neary said.

The slope, the weather, the thin soil due to erosion and the lack of seed-donating trees are all at play here, he said, but can be overcome in time.

He refers to studies elsewhere, showing climate change is having an impact on pinyon-juniper and other landscapes at a faster-than-expected pace.

On Mount Elden, climate change could bring warmer temperatures to promote growth, he said. But it could also compound drought and ultimately slow down recovery due to lack of soil moisture.

Douglas and white fir, Northern Goshawks and Mexican spotted owls were replaced with scrub oak, mule deer and mountain lions in the fire, foresters said.

Aspen, a fire-dependent species, is regenerating on the eastern side of Elden.

'WHOLE MOUNTAIN WAS AGLOW'

Jim Wheeler, assistant fire chief for Flagstaff Fire Department, was a firefighter in Tucson at the time, on break for the week.

He and a friend decided to drive to Flagstaff to fight the fire, just until they had to return to work in Tucson.

He delivered supplies and transported firefighters. He was 26 at the time.

"It was near dusk and the whole mountain was aglow. It was a pretty impressive sight, especially for a desert dweller," he said.