Fire Fallout: Cal expert sees “cascading” loss of wildlife

From Mount Diablo to the Sierras, a significant portion of California’s woodlands are going up in smoke. The impacts on humans are, of course, distressing. And as we’ve reported, the trend of bigger, hotter wildfires bodes to change the essential composition of California’s wildlands: Mixed coniferous forests are likely to contract, while grasslands, chaparral and oak woodlands will probably expand.

But what do the fires mean for wildlife? Will there be a general decline across the board, or will some species prosper while others languish? The question is particularly critical for large infernos such as the Rim Fire, which in the past month has incinerated more than 255,000 acres in and around Yosemite National Park—and still is only 80 percent contained.

We posed our wildlife questions to Reginald Barrett, UC Berkeley professor of environmental science and management and one of the West’s most respected terrestrial vertebrate biologists.

It’s not that wildfire per se is bad for critters, Barrett observes. Rather, the problem is the type of fires we’re seeing these days:  gigantic fires that burn down to mineral earth. In the not so distant past, California wildfires were creeping, low-intensity phenomena that sputtered around on the forest floor, consuming deadwood, conifer needles and other detritus. They seldom if ever leaped into the forest canopy and transformed into apocalyptic conflagrations, as is their wont today. 

Wildlife thrived in the old school fire regimen. Low-level fires created a diversity of “niche” habitats, supporting in turn a rich faunal array. Species that needed old-growth conifers—pine marten, fishers, spotted owls and great gray owls, for example—had abundant habitat. So did species that liked “edge” habitats, most notably the junctures between woodlands and grasslands—black-tailed deer and black bear, for example.

That all began to change, Barrett tells us, when forest management in the state changed.

In the early to mid-20th Century, California’s expansive national forests were true “multiple use” lands, employed for everything from logging to recreation. But from the 1950s on, the emphasis was on timber production: clear-cutting, massive and uniform replanting with conifers, and aggressive fire-suppression. 

This turned many of our public forests into de facto timber plantations, with tightly packed trees that are uniform in age and size.  Such lands are of nil value to old-growth species, and even highly flexible animals such as black-tailed deer, black bear, wood rats and coyotes are hard-pressed to make a living in them. Moreover, decades of fire suppression have allowed the massive accumulation of dead branches and conifer needles on the forest floors, creating a landscape-scale tinder box.

“It’s one thing when you have a fire that burns intensely in a single canyon,” said Barrett. “Normally, most mammals and birds can escape a fire like that. But it’s another when you have something with the dimensions of the Rim Fire. Even large, robust animals have a hard time getting away from that. Also, a fire that burns that hot destroys all the vegetation. Smaller burrowing mammals—pocket gophers, ground squirrels, voles—may survive the fire, but they’ll have a hard time finding enough to eat afterward. And that affects the animals that prey on them. There’s this cascading elimination of wildlife.”

A few changes in forest management could yield great benefits, says Barrett. It won’t take any radical innovations. It’s more a matter of turning back the clock—of returning to the selective cutting that once was standard logging practice, and the re-introduction of prescriptive fire.

“California Indians created resilient, productive wildlands by regular burning,” Barrett says. “We should be burning off fuels in standing timber once every five years or so. Obviously, that’s not happening.”

The U.S. Forest Service has professed a commitment to more enlightened forest management practices, but Barrett claims the agency is still hobbled by a timber production ethic.

“Every time you get a big fire like the Rim Fire, the timber companies start agitating for more access to the national forests,” Barrett says. “They claim more logging is needed. Well, they’re partially right. We do need to cut the smaller trees—we need to thin aggressively. But they’re demanding free access to 24-inch (diameter) trees—the specific trees we want to save, the trees that are resistant to fire, provided the smaller trees around them are thinned and the dead fuels regularly burned. Their nerve really astounds me.”

Barrett places much of the responsibility for the current dire situation on former Cal Forestry School dean John Zivunska, who was an ardent proponent of maximizing timber production. Zivunska wielded great influence in forestry circles in the mid-to-late 20th Century.

In the 1960s, Barrett took classes at Cal from both Zivunska and his philosophical opponent, Harold Biswell. He found Biswell the more convincing of the two.

“Zivunska advocated aggressively for the management practices that have put us in this bind,” Barrett said.   “He supported aggressive fire suppression, at all times and in all places. Biswell, on the other hand, was a pioneer in fire ecology research, and he really understood the advantages of prescriptive fire. I went out on prescriptive burns with him, and I saw that he was right.”

Barrett sometimes found himself in the field with Zivunska and Biswell at the same time, and he recalls that their colloquies were heated. “It was amazing to see those guys go at it,” he recalls. “Neither of them pulled any punches. On the whole though, we’d be a lot better off if we had listened more to Biswell, and less to Zivunska.”

—Glen Martin

Filed under: Science + Health
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