LAST WEEK’S WILDFIRES, which as of this writing have ripped through 85,000 acres of enchanted landscape from the high Mojave Desert to the San Bernardino Mountains, began with a series of more than 100 lightning strikes on the morning of Sunday, July 9. By Tuesday morning, a sleeper fire had erupted in Pipes Canyon, seven miles northeast of Yucca Valley, and by the next night, 42 homes had been destroyed and the land around historic Pioneertown, which sits at the mouth of Pipes Canyon, had turned to what several people described as moonscape: blackened, empty and smoldering.

Two days later, at a town meeting held in the Yucca Valley Community Center, firefighters and public officials from 26 state and local agencies came to answer questions about what was happening. The bright, fluorescently lighted room was packed to overflowing; knots of nervous local residents spilled out into the entryway, consoling each other over the unknown fates of missing dogs and horses, and possibly incinerated homes. And even while the stricken audience gave firefighters three separate standing ovations, confused residents stood to politely convey their anger. This fire, it seemed to many people present, should not have happened the way it did.

“We had no warning,” said Robin Maxwell, a woman from Pipes Canyon who’d been driven from her burning house. “No one told us anything over the radio. I had to drive through a wall of flames to get out of my driveway. People were running for their lives. The last thing I heard on the radio was that Pioneertown was evacuating. But we’re not Pioneertown. Pioneertown is three miles away.”

This fire, however, was devilishly fast — it burned 22,000 acres in fewer than five hours, explained Rick Henson of the California Department of Forestry. “It was such a rapid rate of spread that we were being chased out as well. I don’t think anybody expected the fire to spread as rapidly as it did.”

Anyone who’s enjoyed the hike up Pipes Canyon, through the 40 or so square miles of land owned and protected by the Wildlands Conservancy, might have wondered what there was up there to fuel such hot, voracious flames. Pinyon pines, Joshua trees and junipers — vegetation that neither conducts fire efficiently nor recovers well in its aftermath — stood generously spaced among the soft, tawny granite so familiar in this delicate landscape, the “missing link,” as the Wildlands Conservancy describes it, between the confluence of the Mojave and Sonoran deserts and the San Bernardinos. Small fires that flicker out quickly would have seemed right here, not the wild, sweeping devastation that we’re used to seeing in forests, where conifers need heat to germinate.

“It’ll most likely take decades” to restore the preserve, Wildlands Conservancy project manager D.P. Myers told me later. “Some of the big vegetation, like the Joshua trees and pinyon pines, grow very, very slowly.” Pinyon pines don’t even produce cones for a century; some live for 1,000 years.

After the meeting, while surveying a map of the fire’s perimeter, I asked John Miller, a public-information officer for the U.S. Forest Service, what kinds of conditions led to the fire’s rapid advance.

“I heard it was the grasses,” he said, acknowledging that he was more familiar with the environment higher up in the mountains. “Usually the seeds blow away, but this year they were sheltered somehow, so there was much more grass on the ground to conduct the fire.”

It’s widely acknowledged that non-native grasses such as red brome and cheatgrass have been proliferating in the otherwise near-grassless desert, transforming what would be localized burns into fast-moving blazes. The 1999 Juniper Complex fire that scorched 14,000 acres in Joshua Tree National Park was said to have been one of those grass-fed fires; the damaged Joshua trees have still not recovered.

It’s also well known that those grasses have been fed by nitrogen in the soil: Nitrogen from car exhaust drifts from urban Southern California into the pristine desert, binds to dust particles and fertilizes the ground. In the desert, where native vegetation has evolved to thrive in nutrient-poor dirt, nitrogen feeds the alien plants that conduct fire. (See Judith Lewis’ “What’s Killing Joshua Tree National Park?” and “The Fight for Eagle Mountain,” both from July 8, 2004, at laweekly.com.)

As Matthew L. Brooks of the U.S. Geological Survey wrote in a 2003 article on nitrogen and weeds in the Mojave, “Alien annual grasses produce large amounts of continuous fine fuels that facilitate the spread of fire where fires were historically infrequent.”

It could be argued, then, that Robin Maxwell’s hasty escape was a side effect of Los Angeles smog.

NOT SO FAST, SAID RICHARD MINNICH, an earth-sciences professor and fire-ecology specialist at the University of California, Riverside. Minnich has done significant research on nitrogen deposition himself; he does not deny that it has nurtured invasive weeds in the desert, some of which can conduct fire. But this year’s fuel was probably a less sinister source: “It was the wildflowers,” he told me. “Those wildflowers people adore so much.”

The fire that went through the lower deserts came a year and a half after what Minnich calls “the heaviest rain year we ever saw in that part of the world,” referring to the winter of 2004 to 2005. “That rainfall was triple normal, and there was a tremendous outbreak of herbaceous vegetation.” Not just invasive grasses, but Canterbury bells, pincushions and desert marigolds — native flowers that sprouted, dried up and put down a dense carpet of flash fuel.

“Joshua Tree National Park has the same problem right now. There’s phenomenal fuel out there. Ironically,” he added, “a wet year can burn out a desert town. It’s a lot safer to live in Pioneertown during the worst drought of all time than it is in a wet year.”

But what about nitrogen deposition?

“The problem is that you’ve got to sort out the variables,” Minnich said. “It doesn’t matter how much nitrogen you throw on the landscape when you have a record rainfall. The more it rains, the more stuff grows. Keep it simple.”

On Thursday afternoon while the fires still burned, I drove to the Morongo Valley, where I could see the fire from Highway 62. As I neared the grade where the highway winds through Big Morongo Canyon, the thermometer in my car flipped over to 114 degrees. Flames licked the hills close to the road, and the entire sky had turned a milky terra cotta, a veil of smoke so thick you could look straight at the sun. It was hard to look back at the devastation as something wildflowers wrought. Then again, natural processes are full of contradictions.

D.P. Myers wouldn’t talk about causes and conductors like wildflowers or nitrogen-fed grasses. “I’m not qualified,” he said. He would only discuss the work he’s begun to restore what God or man — or a combination of both — has destroyed.

“We started a massive restoration process the first day we were able to get in there,” he said. “We’ve started our own seed stock to grow native plants. It helps when we’re eradicating the noxious weeds to have something planted in place so they don’t grow up.” And while he wouldn’t go so far as to call the blaze unnatural, “it was extremely big and extremely devastating,” he acknowledged. “I hope we don’t see anything else like this for a very long time.”

LA Weekly