What have we learned about Malibu-area wildfires over the past century?
According to two fire experts, some common knowledge may be less effective than might be hoped.
Speaking during a presentation back in February, Pulitzer Prize-winning journalist Bettina Boxall and fire scientist Jon E. Keeley shared their knowledge of local fire history in a talk entitled “100 Years of Fire in the Santa Monica Mountains.” On March 12, The Malibu Times published the first in a two-part story about the presentation—but fast-breaking news about the novel coronavirus spread pushed the second part of the story off the front page of March 19 and the story has been sitting in drafts for the past seven months. Now, with fire season entering full swing, here is the original story, submitted in March 2020:
Two fire experts questioned the efficacy of often-used fire practices while giving a presentation on “100 Years of Fire in the Santa Monica Mountains” in February. The lecture by Pulitzer Prize-winning journalist Bettina Boxall and fire scientist Jon E. Keeley was held in Pacific Palisades.
Acknowledging fire breaks may have helped in saving property from the Woolsey Fire, Keeley also questioned their benefits.
“Fire breaks produced by bulldozers may have indeed helped to preserve homes, but now these areas are prime for invasion of non-native species,” according to the UCLA professor, noting that non-native plants are not deep-rooted to hold ground and are highly flammable.
Boxall also pointed out that the most destructive wind-driven blazes jump fuel breaks, anyway. Using the state’s $32 million program to create breaks as an example, the journalist mentioned the deadly 2018 Camp Fire, which destroyed the town of Paradise.
“It [Paradise] was virtually surrounded by fuel breaks,” Boxall said. “The town was aware it was in a fire zone. The Camp Fire—as [is] typical—it blows the firebrands right over the fire breaks. It’s rare that a community burns because of an advancing flame front. It’s embers that are carried by these winds that can gust up to 90 miles an hour. These fires can jump eight-lane freeways. This notion of clearing vegetation might work in a relatively tame fire, but it’s not going to work in the kinds of fires that Malibu experiences.”
Keeley hypothesized that clearing an area might encourage the flow of embers through landscape and suggested that healthy trees are ember catchers that might save a house.
“Embers have to land on dead fuel to ignite,” Keeley said. “If you surround your house with green trees, that might be a solution. Some say species don’t make so much difference as how they are treated. Eucalyptus are well known in most people’s minds as being highly flammable, but they’re not if their lower branches are trimmed off and the debris underneath them is cleared. Pine trees are probably bad. Evergreen oaks are good because they have enough moisture in their foliage that you can’t get them to ignite with embers.”
He also pointed out that structures are, themselves, fuel for flames.
“Houses are fuel. A fire doesn’t distinguish. Houses are also filled with fuel,” Keeley said. Once radiant heat builds, nearby homes can catch fire. This accentuates the need for home hardening including proper roofs, enclosed eaves and correctly meshed vents.
According to Boxall, not all fire-mitigating strategies are universal.
“A lot of what you hear in the media has to do with fires in other parts of California,” she said. “The southern part is shrublands and a lot of people—10 times the population of the northern part. Four hundred seventy-five fires, versus 4,700 here. Many of the fires in Northern California are started by lightning. Here, 99 percent of our fires are started by people.”
[That was proven true by the dozens of fires that started due to lightning in Northern California this August.]
The two experts claimed “in the last decade, all our [Santa Monica Mountains] big fires have been started by power line failures. This is a major issue we need to deal with.” Utilities’ answers have been Public Safety Power Shutoffs and that means people might use gas-powered generators.
“That’s a real concern,” Keeley said. “From the power company’s point of view it’s less an issue because their shareholders aren’t going to be responsible for those fires, but it does create an additional (ignition) source.”
The drought from 2012 to 2018 also caused dieback in the Santa Monica Mountains, leaving massive dead vegetation. But, Boxall pointed out, “Wind-driven fires can burn in the same places they’ve recently burned.” And if landscape is burned at intervals of less than 30 years, some flora is vulnerable to extirpation. Chaparral is damaged when it burned too frequently.
“California is a huge state with some of the greatest biodiversity in the entire country,” Boxall said. “Each eco region has different fire regimes. There is not one template that can be used for the entire state.”
Keeley encouraged prevention and hardening power lines—“Postponed maintenance is a problem and apparently what caused the deadly Camp Fire.”
Since fires are mostly started by humans near roads, some exurb communities are using cement K-rails preventively to help stop ignitions from cars, cigarettes and arson.
During the presentation, someone asked about animal survival.
“Small rodents may survive underground by sheltering in place,” Boxall said. “If the fire passes quickly, they may not lose oxygen in their tunnels. Larger animals and birds don’t do as well in smoldering fires. Birds and deer flee and recolonize, but it’s problematic if there’s a highly fragmented landscape due to development.”