Reposted from California Alumni Magazine
Detail of photo by Bobby Lee / The Daily Californian
Expert: Grizzly Peak Wildfire Response Reveals a Potential Flaw
Last week's wild fire on Grizzly Peak Boulevard ended up scorching about 20 acres of brush and grass near the Lawrence Berkeley National Laboratory, with no major damage to property and no loss of life. That was due in large part to a fuel reduction program pursued by Berkeley Lab since the 1990s, says Scott Stephens, a professor with UC Berkeley's Department of Environmental Science, Policy, and Management and one of the country's foremost wildfire experts.
“The lab has done a good job of treating blue gum [eucalyptus] stands around their facilities and generally removing or reducing fuels,” says Stephens, noting the ubiquitous eucalypts that grow across the East bay hills are notorious for their flammability. Due at least partially to Berkeley Lab's efforts, says Stephens, the fire never “crowned”—that is, it didn't leap up the “fuel ladders” of brush and branches to the interconnected canopies of the trees, then rage across the landscape.
Firefighters also were able to jump on the flames in short order, due in large part to a signage system put in place by Tom Klatt, Stephens' predecessor at Berkeley.
“I try not to promote draconian scenarios, but I am concerned about them,” Stephens says. “A fire driven by a strong east wind on a hot day would've acted very differently.”
“Tom was concerned about just this kind of situation: a fire breaking out on Grizzly Peak Boulevard, with firefighters delayed because there are so many twists and turns to the road and it can be difficult to determine location,” Stephens said. “So he was able to get a series of sign posts installed up there. Last week's fire started at sign post 14, and firefighters were able to respond very rapidly because they knew exactly where they were going.”
But the East Bay Hills dodged an incendiary bullet for another reason, Stephens says: On the day the fire ignited, the weather was mild and a west wind was blowing, more or less pushing flames away from Berkeley Lab and the UC Berkeley campus. If the fire had started on a hot day with an east wind—the conditions that prevailed during the disastrous Oakland Hills fire of 1991—things might have concluded tragically.
“I try not to promote draconian scenarios, but I am concerned about them,” Stephens says. “A fire driven by a strong east wind on a hot day would've acted very differently. It not only would've burned very quickly, but where particularly volatile fuels such as eucalyptus are concerned, it would have thrown embers miles ahead, starting hundreds of spot fires that would also burn explosively and merge. That's what happened in 1991.”
Normally, wildfires burn more rapidly uphill than downhill, observes Stephens, but in extreme conditions such as those that characterized the Oakland Hills Fire, “the fire overwhelms the topography. If last week's fire had occurred under Oakland Hills fire conditions, there would've been impacts to university property. I'm particularly concerned about the Clark Kerr campus dormitories. They seem at significant risk.”
Stephens has long supported major fuel reduction programs for the East Bay Hills, and was particularly distressed when FEMA pulled funding for a plan to remove eucalyptus and restore native vegetation on land owned by the university along Claremont Canyon. But fuel reduction, he avers, is not enough. Public facilities in the East Bay Hills also need effective response programs. Berkeley Lab evacuated its employees during the Grizzly Peak fire, says Stephens, “and I watched from the campanile for about 45 minutes as cars slowly snaked down the hill. People were particularly vulnerable at that time. If the fire had burned down that road rapidly, as you could expect with a strong east wind, they would've been in trouble. The natural instinct for people surrounded by wildfire is to get out of their cars and run, which can put them at even greater risk. Fatalities occurred during the Oakland Hills Fire because of that reaction, and it happens regularly during Australian wildfires.”
Many of Berkeley Lab's buildings are heavy concrete structures that could be largely impervious to wildfire, particularly given the aggressive fuel reduction policies the lab has pursued for the past 20 years, Stephens observes.
“I think it might be time for them to consider a shelter-in-place policy for their wildfire response strategy,” he says. “It would warrant an evaluation, at least. And they might also consider additional entrances and exits, a major reason the cars were so slow in getting out is because access is so limited. I also think UC needs to revisit and update its evacuation policies for its buildings, including the Clark Kerr dorms.”
Reposted from the UC Berkeley News
A study led by ecologists at UC Berkeley has found significant flaws in the research used to challenge the U.S. Forest Service plan to restore Sierra Nevada forests to less dense, and less fire-prone, environments.
An example of a mixed-conifer forest in the Sierra de San Pedro Martir National Forest, Baja California Norte, Mexico. This forest experienced active, natural fires until the 1970s. (Photo by Carrie Levine).
Until recently, the consensus among forest ecologists was that before European settlers arrived in the Sierra, the forests were mostly open conifer forests dominated by big trees and low-to-moderately severe fires every eight to 12 years. The Forest Service recently released a plan to restore the range's forests back to this state following decades of fire suppression and timber harvesting regulations, which have created dense, fire-prone forests.
But recent studies, using a newly developed methodology, have argued that the Sierra Nevada was actually a more dense forest than the consensus view. These new studies were used to back a lawsuit to stop the agency's plan to restore Sierra forests following the 2013 Rim Fire. The Berkeley study refutes the conclusions of these studies and identifies flaws in their methods.
“We went through the data and showed that, in every case, this method estimated that the density of trees was two to three times higher than was the reality,” said Carrie Levine, a Ph.D. student of forest ecology at Berkeley and lead author of the study.
The study was recently published online in the journal Ecological Applications. Berkeley professors John Battles and Scott Stephens and research scientist Brandon Collins were co-authors on the publication. Also involved in the study were researchers from Harvard Forest, the USDA Forest Service Pacific Southwest Research Station, the University of Montana, Utah State University, University of California, Davis, and the USDA Forest Service Pacific Southwest Region.
An example of a densified mixed-conifer forest in the Plumas National Forest in Northern California. Fires have been suppressed in this forest for more than 100 years. (Photo by Carrie Levine).
When the U.S. was divvying up land in the West in the late 19th and early 20th centuries, the General Land Office performed surveys so that the land could be parceled and sold. Land was divided into square-mile blocks, with markers used to indicate every corner point. In case a marker was moved, so-called “witness trees” near the stake were identified as reference points. The result of this data is a grid survey of the entire American West.
Using this historic field data, two ecologists at the University of Wyoming, Mark Williams and William Baker, developed a method that claims to calculate the area that a tree occupies, which is then used to calculate a forest's density. This approach is based on the observation that trees create space to keep other trees from cramming next to them, and that this space correlates to a tree's species and size.
To assess the validity of this area-based method of density estimation in the Sierra Nevada, Levine and her co-authors assembled data from plots of mapped trees across the Sierra and Baja California, Mexico. They tested the performance of the area-based method in these mapped stands where the true density was known.
Levine and colleagues found that the area-based method has two basic flaws when applied to the Sierra, the most notable being an inability to actually predict the area that a tree occupies based on its species and size due to a weak relationship between these variables. The other flaw was a failure to account for differences in the number of trees sampled at each corner. The methodological flaws led to an inflated number of trees estimated in a pre-European Sierra Nevada forest, Levine and colleagues argue.
“We have a mapped plot where every tree is measured, so we know the true density,” Levine said.
The study is important not only for the current state of the Sierra Nevada, but for its future.
“As climate changes, we want to have an accurate understanding of the past. This allows us to manage for forests that are resilient to the changes we're expecting in the future,” Levine said.
Reposted from UC Berkeley's Department of Environmental Science, Policy and Management
In response to California's growing tree mortality crisis, the Little Hoover Commission held a public hearing on California Forest Management yesterday (January 26) at the state capital in Sacramento.
Professor Scott Stephens, a fire scientist in the department of environmental science, policy, and management, delivered the opening remarks. He provided background on the causes and magnitude of tree losses happening across the state. "Our forests are not in a resilient condition," he said. "Past management actions, including fire suppression and logging focused on large trees have produced forests today that are much more vulnerable to fire and drought-related mortality." Stephens made suggestions for legislation, policy, and forest management techniques that could help restore resilience to California's forest ecosystems and prevent future mortality crises. He also offered ideas on how the state could better work with private landowners as well as the federal government to promote healthier forests.
Read Professor Stephens' complete testimony, as well as the those of others who spoke at the meeting, on the Little Hoover Commission's website.
Reposted from UC Berkeley News
An unprecedented 40-year experiment in a 40,000-acre valley of Yosemite National Park strongly supports the idea that managing fire, rather than suppressing it, makes wilderness areas more resilient to fire, with the added benefit of increased water availability and resistance to drought.
A severe fire cleared an area of forest in the Illilouette Creek basin in Yosemite National Park, allowing it to become a wetland. Wetlands and meadows provide natural firebreaks that make the area less prone to catastrophic fires. (Scott Stephens photo)
After a three-year, on-the-ground assessment of the park's Illilouette Creek basin, UC Berkeley researchers concluded that a strategy dating to 1973 of managing wildfires with minimal suppression and almost no preemptive, so-called prescribed burns has created a landscape more resistant to catastrophic fire, with more diverse vegetation and forest structure and increased water storage, mostly in the form of meadows in areas cleared by fires.
“When fire is not suppressed, you get all these benefits: increased stream flow, increased downstream water availability, increased soil moisture, which improves habitat for the plants within the watershed. And it increases the drought resistance of the remaining trees and also increases the fire resilience because you have created these natural firebreaks,” said Gabrielle Boisramé, a graduate student in UC Berkeley's Department of Civil and Environmental Engineering and first author of the study.
Boisramé and co-author Sally Thompson, a UC Berkeley ecohydrologist and assistant professor of civil and environmental engineering, found that even in the drought years covered by the study, the basin retained more water than similar areas outside the park. That translated into more runoff into the Upper Merced River, which flows through Yosemite Valley, at a time when other rivers in the surrounding areas without a restored fire regime showed the same or decreased flow.
“We know that forests are deep-rooted and that they have a large leaf area, which means they are both thirsty and able to get to water resources,” Thompson said. “So if fire removes 20 percent of that demand from the landscape, that frees up some of the water to do different things, from recharging groundwater resources to supporting different kinds of vegetation, and it could start to move into the surface water supplies as stream flow.”
The study is published in the current issue of the journal Ecosystems.
If the results are confirmed from other studies, including the UC Berkeley team's new project analyzing the Sugarloaf Creek Basin in Sequoia and Kings Canyon national parks, they could alter the way the federal government as well as water districts deal with fire, benefiting not only the forest environment but potentially also agriculture and cities because of more runoff into streams and reservoirs.
“I think it has the potential to change the conversation about wildfire management,” said co-author Scott Stephens, a fire expert and UC Berkeley professor of environmental science, policy and management who has studied the Illilouette basin since 2002.
This “wildfire management” strategy is counter to the federal government's 110-year-old Smokey Bear policy, which is followed throughout the West and emphasizes suppressing fires wherever they occur for fear they will get out of control. With persistent drought and a warming climate, the U.S. Forest Service budget is increasingly going to firefighting. On most federal land, only forest thinning and human-initiated prescribed burns are allowed as a way to manage the trees and underbrush.
Stephens noted, however, that these agencies have recognized the folly of total suppression — thanks in part to his own studies throughout the Sierra Nevada over several decades — and current draft wildland management policies for three of the state's national forests allow active wildfire management in up to 60 percent of the forests.
The value of forest clearings
Wildfire management, as opposed to suppression, comes with major changes in the way the forest looks, Stephens and Thompson said. Unlike the dense stands of pine and fir most people associate with Yosemite and similar mid-elevation Sierra Nevada and Rocky Mountain forests, the Illilouette Creek basin has thinner forests and more clearings with dead trees.
Graduate student Kate Wilkin gathering data in the field in the Illilouette Creek Basin, which bears the scars of many natural fires. Gabrielle Boisramé photo.
“There is much more dramatic structural change in this forest than most people would probably feel comfortable with,” he said. “You are talking about low-density forests and gaps of 4 or 5 acres, up to maybe 100 acres. These are the result of major fires about every decade or so, large enough to cause tree scarring and affecting as much as one-quarter of the basin.”
These fire-caused clearings, however, act as natural fire breaks and make the area resistant to catastrophic fires such as the 2013 Rim Fire in the western part of the park, which burned 250,000 acres and left patches up to 20,000 acres in which not a single conifer tree survived. These areas could take a century to recover, Stephens said.
“In the Illilouette basin we lost about 20 percent of the forest cover, but there was a 200 percent increase in wetland vegetation: meadows starting to reemerge from forests that have probably encroached on historical locations,” Thompson said. “That sets us up to think that this new regime should be leakier as far as water goes — leaky in the way that suits us as a society.”
Even if these wildfire management techniques don't produce more runoff, Thompson added, “I think it is a fabulous result in terms of forest management if you end up with a healthier forest with some better intact aquatic habitat, even if you don't see a drop of water further downstream. It is still the right thing to do from an ecological point of view.
“Bottom line, this strategy might be a triple win-win-win for water, forest structure and fire risk,” she said.
The ‘jewel' of Yosemite National Park
The findings are the culmination of a 14-year study led by Stephens and his UC Berkeley colleagues to learn how monitoring natural, lightning-caused fires with a bias toward letting them burn affects the landscape, the vegetation and the groundwater. Only four areas in the western U.S., including two in California — the Illilouette Creek basin and the Sugarloaf Creek basin — have allowed lightning fires to burn in large areas for decades.
Graduate student Gabrielle Boisramé crossing Illilouette Creek in Yosemite National Park. (Diane Taylor photo)
Most studies of different ways to manage wildland fires have been limited to a few hundred acres, and it's hard to extrapolate from such limited experiments to an entire forest. Luckily, Yosemite National Park started its experiment in 1973 — spurred by a 1963 report authored by the late UC Berkeley forester Starker Leopold — to let nature take its course in the Illilouette Creek watershed, stepping in only when fires in the basin threatened to get out of control or sent too much smoke into Yosemite Valley two miles to the northwest.
“This is the first study that looks at fire regime restoration on a watershed scale with empirical data,” he said. “Others do smaller areas or modeling, but this is 40,000 acres — a big place — over many years.”
One reason the basin was chosen was that it was surrounded by granite walls, which naturally prevented fires from spreading outside the basin. It had not been burned by the indigenous tribes of the region, which often set fires to increase acorn production, and had no history of prescribed burns. In fact, it saw only natural, lightning-caused fires except for an interval of nearly a century — 1875 to 1972 — when the park suppressed all fires.
While Stephens and his many students documented the changes in fire over the past 400 years, Boisramé and Thompson analyzed aerial photos to document vegetation change. Then, with the help of installed sensors and more than 3,000 soil moisture measurements throughout the basin, the team was able to estimate the amount of water in the landscape today versus in the past. They found similar or marginally drier conditions where forests had been replaced with shrubs, but these were balanced by much wetter conditions in small areas where meadows expanded.
They observed more snow reaching the ground because of the clearings, and more snow remaining during the spring, delaying runoff. And in recent drought years, when surrounding basins saw more trees die, there was almost no tree mortality in the Illilouette basin.
“In order to really understand whether this approach should be part of our management toolkit, I would recommend that we give it a crack in a few other places,” Thompson said. “This appears to be a promising management strategy without significant harm and with several very strongly quantifiable benefits and several very suggestive outcomes.”
Boisramé, who spent the past four summers sampling and camping in the Illilouette Creek basin, emphasized that this is not a strategy that would work everywhere. But in wilderness areas where wildfire management is being considered because of its safety benefits — to reduce underbrush and eliminate fuel for out-of-control and catastrophic fires that risk lives and property — the ecological and hydrological benefits are a big bonus. Areas with similar elevation and climatic conditions to the Illilouette basin, and thus perhaps suitable for managed wildfire, comprise about 18 percent of the Sierra Nevada, though the strategy may work at lower elevations as well.
“The whole ecosystem will be better off if we let the natural fire process back in,” she said.
The research was supported by a grant from the federal Joint Fire Science Program.
Reposted from the UCANR News Blog
Even though there has been a deficit of fire in California forests for decades, their future is not hopeless, said UC Berkeley fire science professor and UC Agriculture and Natural Resources researcher Scott Stephens in an interview with Craig Miller on KQED Science.
"The next 25 to 30 years are paramount. If you begin to do restoration, reduce density, make forests more variable in pattern, and less fuel, when you have episodes of drought and fire, it's going to be fine. The forests have been doing this for millennia. It's going to be fine," Stephens said.
However, under current conditions, in which fires have been regularly suppressed, the situation is dire.
"The forests used to burn every 12 to 15 years, but most places haven't been touched for 50 to 100 years. Today we have areas with 300 or 400 trees per acre, where you used to have 50 to 80," he said.
Even though, Stephens said he is an optimist. "There's still opportunity today to do restoration, so that when it does get warmer and warmer, as projected, the forests will be able to deal with that, deal with insects and disease and keep themselves intact."