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Forest Renews Itself in the Wake of 'Devastating' Lake Fire

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Behind an incinerated Wilderness sign, Chad Hanson looks at a rejuvenated aspen grove | Photo: Chris Clarke/KCET

In June, the Lake Fire near Big Bear in the San Bernardino Mountains burned an area the size of San Francisco: 31,359 acres, just shy of 49 square miles. My neighbors and I in Joshua Tree watched nervously as the bright orange flames lit the night sky to the west, and smoke hung heavy for weeks in our skies and our lungs.

It wasn't a huge fire by Californian standards, but it was intense, with individual flames so large we could see them from 35 miles away, and fire crews struggled to cover ground on the steep and broken slopes of San Gorgonio Mountain's north face. For three weeks we watched and crossed our fingers as neighbors upslope were evacuated, and when the fire finally petered out in early July with just one dwelling burned our relief was ambiguous: that one house belonged to someone many of us in town knew. This fire was personal.

Three weeks, $40 million in firefighting costs, five injuries, and that one lost home later, the Lake Fire quietly burned itself out, leaving a wide swath of devastation in its wake. Or so I imagined. But on this bright morning in early October, hiking through some of the worst of the burn, I'm surrounded by green leaves, flowing water, and the bright songs of birds. If this is devastation, it's the hopeful kind.

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I've hiked into the hills above the Heart Bar Campground, up in the headwaters of the Santa Ana River, to take a look at the forest three months after the Lake Fire went out. With me is Chad Hanson of the John Muir Project, a forest ecologist who lives in nearby Big Bear. (Full disclosure: the John Muir Project is a project of Earth Island Institute, for which I worked a decade ago.) I'm a little out of breath: we've just hiked in two miles up and over the ridge between the Santa Ana and Fish Creek. It's just a moderate climb of about 400 feet and change, but at 7,200 feet we're about 5,000 feet higher than where I woke up this morning.

Hanson's used to the altitude, so I breathe while he talks. We're in the popular Aspen Grove area, right at the north edge of the San Gorgonio Wilderness, about 1,500 acres of land designated a "high-intensity" burn area in the Lake Fire. The grove's aspens were hit hard by the fire: the forest is blackened, as is the Forest Service's wooden sign announcing the wilderness boundary.

And yet this forest isn't killed. Just three months after the Lake Fire, the aspens are coming back, and they're doing so at a rate that even surprises Hanson, new trees already three and four feet tall growing throughout the forest. Nearby willow shrubs, not to be outdone, are sporting new growth five and six feet tall.

"The fire didn't kill the aspens here," says Hanson. "It just killed the top growth. The roots came through fine. I'd guess there are about five times as many aspen trees in this grove now as there were before the fire."

A giant aspen grove can often be a single organism, a network of subterranean roots with hundreds of trees growing from it, all germinated from a single seed centuries ago. Each tree may live 100 years or less but the organism lives on, growing new trees to replace those that die. Whether the Aspen Grove here on Fish Creek is one organism or several, the fire seems to have damaged it only in the same sense that a mower damages a healthy lawn. The top portion removed, the grove is growing back.

That's not to say the fire hasn't changed the aspen grove radically. Above the last three months' new shoots, blackened aspen trunks stand stark against a flawless blue sky. Where a year ago the breeze would have raised the sound of a million aspen leaves clapping softly, it now whistles a little through bare branches. You can still smell the fire: it's faint, as though someone in the neighborhood burned some cordwood in a fireplace a few hours ago.

The smoke scent is a minor note. Mostly, there's sun, the song of birds and the busy whine of insects, and the musical passage of Fish Creek as it heads clear and cold over one blackened shelf, and then another.

I'd expected the Lake Fire's high intensity burn area to be somber, promising renewal only in the abstract for people who could spot subtle signs of recovery. Instead, the place is cheerful, the life in it exuberant.

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Wildflowers grow in the high-intensity burn area of the Lake Fire | Photo: Chris Clarke/KCET
 

We fight forest fires. It's what we do. The notion that naturally occurring fire is wholly destructive is deeply ingrained in modern American culture. It predates Bambi. It predates Smokey the Bear. Though earlier human societies had a more measured relationship with wildfire, the attitude toward wildfire in the American West has been almost uniformly negative since the so-called "Big Blowup" of August 1910, in which an estimated 3 million acres of forests burned in 11 western states, and at least 85 people killed. In the wake of that fire season, the U.S. Forest Service -- just five years old when the Big Blowup hit -- determined as an agency that prevention was its main strategy for managing forest fires, and in fact a main strategy of the agency for all aspects of forest management.

A hint of one possible reason can be gained from U.S. government's assessment of the damage done by fires in the Big Blowup. As reported by the Forest History Society,

A "board foot" is a standard measure of a tree destined to be cut down and then cut up for lumber. A standard two-by-four ten feet long is about 4.4 board feet. Aside from the obvious tragedy involved in the human death toll from the Big Blowup, the devastation with which that nascent Forest Service was concerned in 1910 was with the loss not of western forest ecosystems, but with the commodities that could be extracted from those ecosystems.

Here's another hint: unlike the National Park Service, the Bureau of Land Management, the U.S. Fish and Wildlife Service, and other federal agencies tasked with managing and preserving public lands and the wildlife that depends on them, the U.S. Forest Service is part of the U.S. Department of Agriculture. Our National Forests have long been seen, first and foremost, as a crop, and anything that threatens the harvest of board feet is a crisis to be fought.

For more than 70 years after the Big Blowup, fire was treated as an out and out enemy by federal agencies. During that time, though, the science marched off in a different direction. By the time the forests of Yellowstone National Park famously caught fire in 1988, a few federal land management agencies had nuanced their position somewhat. A century of fire suppression had changed the West's forests: fuel loads were increasing because the frequent small fires that would have consumed dry brush, grasses, and small trees had been prevented. Gone were the "open, park-like" forests settlers had found in the 19th Century. Ecologists began to study the history of fires in the Western states, including a lengthy prehistoric record of Native people setting deliberate fires to manage the landscape.

Science was a few steps ahead of public awareness: the National Park Service took a huge amount of public criticism in 1988 for letting wildfires burn in parts of Yellowstone where public safety wasn't directly threatened. But with the advent of controlled fires as a fuel reduction tool, more and more members of the public have come to realize that absolute fire suppression isn't the best approach to managing fire.

Which doesn't mean, however, that high intensity wildfires have been accepted as a natural part of the larger ecosystem of western forests. The Wikipedia entry on the Yellowstone fires of 1988 contains an apt summation of land managers' ambivalence toward fire:

In other words: We used to think fires were bad and put them out immediately. Now we know better and let them burn, because that reduces the amount of fires to which we would "lose" area. Even though we grant lip service to the benefits of fire, we still see them as a loss to be minimized. A let-burn policy isn't an acceptance of fire's value. It's merely fighting fire with fire.

The notion that even high-intensity fire can be a good thing for forest ecosystems, that forests and their denizens might suffer if not allowed to burn, still seems to go against all that is right and good. California media outlets, these days, warn of a coming cataclysm as drought-stressed trees make the state's forests more likely to catch fire, in tones alarmist enough to suggest those coming fires are a dire threat to... to something.

Here in the renewing aspen grove, those warnings seem distant indeed.

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A new Aspen Grove grows in the ashes of the old | Photo: Chris Clarke/KCET

"This forest is responding like it's already next spring," says Hanson, absently petting a five-foot clonal aspen sprout. It seems true. Next spring, given a modicum of rain or snow, the Fish Creek watershed will almost certainly burst into bloom, but hints of that color to come already dot the sunnier parts of the forest. From where we stand we see purple Erigeron in full bloom, bright crimson Indian paintbrush on sunny slopes, native goldenrod with yellow flower heads nodding under their own weight, all of them attracting a startling diversity of butterflies.

Butterflies aren't the only insects that see opportunity here. Even before the Lake Fire was brought under control in July, infrared-sensing native beetles started heading toward the burn from miles around. Finding trees newly killed by the fire, they lay their eggs under the bark. Those eggs hatch out and larvae begin tunneling through the wood.

That process causes distress to those who measure standing trees in board feet: the boring can reduce or destroy a tree's value to lumber mills. But from the perspective of other users of the forest, the beetles greatly increase the trees' value. Woodpeckers are among the first birds to arrive in a freshly burned California forest, and as they mine the snags' trunks for beetle larvae they also take time to create new real estate opportunities, in the form of cavity nests in the standing snags.

"A male downy or hairy woodpecker will dig out three or four cavities," says Hanson. "His mate will select one and they'll move in." That leaves two or three perfectly good new homes for other birds, and potentially for small mammals.

Downy and hairy woodpeckers, flickers, and (farther north in the Sierra Nevada) black-backed woodpeckers move into a burned forest within weeks of the fire to carve out new homes. Other birds, so-called "secondary cavity nesters" such as sapsuckers, can only use snags once they've been dead for a few years, after the wood has weathered a bit and become softer.

As for mammals, you might expect a huge amount of carnage during a large fire such as the Lake Fire. But even those mammals too small to cover ground quickly and escape the fire have an escape route: they go down. "Burrowing animals can easily weather even a high-intensity fire," says Hanson. "Soil temperatures don't change much once you get farther down than a couple inches."

"Pocket gophers do really well in the wake of a fire," Hanson adds. " They have networks of burrows that keep them safe from fires, and then" -- Hanson gestures at the exuberant regrowth of aspen and willow -- "well, they eat roots and shoots. There are a lot of roots and shoots here right now."

There are a few pocket gopher burrow entrance holes here and there throughout the aspen grove; little mounds of lighter soil against the charcoal-enhanced topsoil. I wonder how much carbon those gophers will sequester over the next few years, tilling the remains of the Lake Fire down into the soil a foot or three deep.

Some larger mammal has been sampling the aspen leaves: I see a few shoots that have had their leaves trimmed off up 14 inches or so off the ground. Was a rabbit responsible, or a woodrat? Hard to say, and the newly blackened mud in Fish Creek is so crisscrossed with animal tracks it's hard to identify any of the smaller ones.

"This is just a great example of how the environment can thrive after a high-intensity burn," says Hanson. "The soil has this sudden infusion of nutrients, from the ash from the trees and shrubs. There's more sunlight now, and more opportunities for plant growth. And the animal population responds to that."

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A month ago this Jeffrey pine might have been written off for dead. Now, a flush of healthy needles attests to its survival. | Photo: Chris Clarke/KCET

We hike back up over the ridge to our vehicles, through a stretch of mixed medium- and low-intensity burn. On our way in, Hanson had pointed out one Jeffrey pine after another that he guessed had been marked off as dead by the Forest Service. Most had verdant new green needles crowding out the fire-damaged brown ones. When examined by foresters, those green needles had been lurking in leaf buds, protected from the brief flash of heat that had killed the trees' existing needles. Now, in a flush of new growth -- the phenomenon is called "flushing" -- the Jeffrey pines were showing that reports of their death had been exaggerated.

Other native plants show similar patchy damage. Many of the hillside's black oaks had been killed to the ground; of those, most of the blackened trunks sport new growth from the soil level, grown three or four feet in three months. Manzanitas, with a reputation for being among the most flammable of native plants, had burned profusely in some places, halfheartedly in others. A few manzanitas along the road are half consumed, the other half as green as pampered garden specimen plants.

I'm struck, once again, by how cheerful the scene seems. Far from being a scene of devastation, just three months after the Lake Fire the general feel of the landscape is one of exuberant renewal.

A study published some years back in the journal Forest Ecology and Management suggested that before 1800, about 1.8 million hectares of California -- 4.4 million acres and change -- burned in an average year. The total California acreage burned in 2015, in a year widely regarded as a serious fire year, was 814,485 acres -- less than 20 percent of that prehistoric average.

I begin to wonder, as Hanson and I stop halfway to our cars to watch a female hairy woodpecker probe a new snag for beetle larvae, whether the state of California doesn't actually suffer from a fire deficit. A century of fire suppression has created an artificial forest, one with fewer of the patchy, regenerating high-intensity burn areas. It's a truism in ecological sciences that boundaries between habitats are especially rich in biodiversity. By suppressing fires for a century, have we reduced California's forest biodiversity?

The answer may partly lie in how a forest like this changes in the first decade after a burn. Fortunately for me, I don't need to wait around for a decade to find out: Hanson and I reach our cars and head off for the site of the Butler Fire, which burned about 14,000 acres not far from here in 2007. He wants to show me what happens when a burned forest is allowed to regrow without post-fire logging or other interventions.

I'll describe that hike in Part 2 of this series.