Experts, UC scientists discuss wildfires in the state’s riskiest regions

Wildfires are nothing new in California’s history, but the magnitude and frequencies of recent fires across the state has proven...

Wildfires are nothing new in California’s history, but the magnitude and frequencies of recent fires across the state has proven that these disasters won’t be leaving anytime soon, experts say.

And for communities on the border of wildland and urban areas, also known as the Wildland-Urban Interface (WUI), that means their risk of danger or property destruction is only increasing without proper mitigation.

The record-breaking wildfire season of 2020 saw 4.2 million acres burnt statewide, and 2021 is already bringing a hot and heavy start to the fire season.

Fires are hitting urban areas more frequently than before, and the intensity brings devastating effects to the community, said Michael Gollner, an assistant professor of mechanical engineering at University of California at Berkeley who specializes in fire model development and emissions.

“We’re not talking about a fire that went through brush, we’re talking about a fire that jumped over a multiple-lane highway through commercial area and into a suburban community,” Gollner said in reference to the major losses during the 2017 Tubbs Fire in the North Bay. “This is a different beast we’re tackling.”

Along with Gollner, a coalition of wildfire, environmental and health experts across state agencies and University of California campuses held a webinar Wednesday morning to discuss what we know (and don’t know) about WUI fires, and how research-backed solutions can mitigate their effects.

Susan Hubbard, the associate laboratory director for the Lawrence Berkeley National Laboratory, said that fires from the past few years have revealed the need for research on all fronts.

“Wildfire is, in essence, an indivisible challenge,” Hubbard said. “That means that it can’t be tackled by any single technology or approach, any single discipline or any single organization.”

A full agenda of the symposium can be found at

Building resilient forests

Forest management does not mean preventing fires at all costs. We actually need more fires in our forests, called prescribed fires, to prevent the catastrophic blazes the state has seen, said Jessica Morse, deputy secretary for California Natural Resources Agency’s Forest Resources Management.

Fires do have their benefits in forest ecology: for example, they can help geminate seeds and clear out dead vegetation. The recent violent fires go beyond nature’s routine clearance, and are a result of anti-fire forest management approaches, Morse said.

“What we’ve been seeing in fire-suppressed forests is that they’re too dense. The fire goes into the tree canopy and it actually kills everything, rather than just weeding out weaker species and weaker trees, and it burns deep and hot and devastates the watershed, too,” Morse said.

One main goal for the state’s forest management is reducing these fuel loads to their natural intensity, so that when a fire does come through, they burn at a natural, controlled rate. Morse said that less fuel means less heat intensity, and fewer embers that fly off into communities.

Fuel breaks, which are gaps of land in forests that have minimal vegetation, are one of the strategies Morse suggests implementing, especially around roadsides. 30 to 60 percent of vegetation can be cleared between a row of trees to lower heat intensity, and it gives first responders a change to make their way into a fire easier.

“We saw in Paradise, an 8-mile-long fuel break that arrested the flank of the Camp Fire and saved the town of Stirling City,” Morse said. “We’ve seen these in action over and over last summer, emergency fuel breaks that had been put in just saved lives and got people out of really dynamic fires.”

Prescribed fires have already played a role in protecting WUI areas in places like Florida, which sometimes burns more than 2 million acres annually, according to Lenya Quinn-Davidson from UC Agriculture & Natural Resources.

“If any of you have traveled in Florida, or maybe some of you have even burned in Florida, you’re often right near homes, you’re seeing smoke right behind the grocery store, in the back 40 on private property,” Quinn-Davidson said. “Prescribed fire is part of the culture there, and it’s really integrated in and amongst human habitation, so it’s a great example and somewhere we should really be looking to understand the role of prescribed fire.”

There are some roadblocks, however, and fuel reduction isn’t the only solution to fire management, she said. The first steps involve getting more community members trained, strategic projects planned out and adequate equipment supplies, along with greater relief funds and liability protections.

“If we invest in people and build capacity, the acres will follow,” she said.

Community hardening

Creating “defensible spaces” and “hardening homes” are two buzzword tactics that circled Wednesday’s discussion, and with good reason: a recent Cal Fire damage inspection revealed that 93 percent of all structures that catch fire will be completely destroyed, and 70 percent of those structures are homes.

“It goes without saying, and we already knew this, that we want to prevent structures from igniting in the first place. That’s the goal, because once they ignite, the chances of limiting the damage become very minimal,” said Steve Hawks, staff chief of the Wildfire Planning & Engineering Division for Cal Fire.

Cutting back vegetation and burnable fuels on private property is one way to make a defensible space, along with a few home adjustments like adding weather stripping around the garage door or covering attic vents with fire-resistant mesh panels.

Materials used to build a structure also makes a difference. Structures built after the 2008 California Building Code Chapter 7A, designed for standards for buildings in high-risk fire areas, are less likely to be destroyed, Hawks said.

One of the greatest challenges in hardening communities is retrofitting the older structures that aren’t meeting these standards, which might require expensive renovations like roof or window replacements. The state currently plans to allocate funds for homeowners in WUI areas effective January 2022 in its Home Hardening Program.

Researchers admit that the full extent of structure-to-structure fire spread in WUI areas and standard test methods based on realistic exposure are still unknown.

“We know that home hardening actions work, but we need to the science to help us determine additional home hardening actions, because home hardening can be very costly,” Hawks said. “Wherever we can determine good mitigation strategies that lower the cost of implementation will help us out with the hundreds of thousands of structures that are out there that need retrofitting.”

Landscape scale strategies

Broad data patterns on climate change, frequency of fires or dry vegetation do not tell the whole story on California’s wildfire problems, according to Max Moritz, statewide wildfire specialist at the UC Cooperative Extension. People and the changes they’ve made to the landscape matter, too.

“That’s because we have done a lot of things to our landscape at finer scales,” Moritz said. “Look at the power line infrastructure. We’ve got road networks, we’ve got housing developments at different densities across the landscape.”

Moritz, with the help of other researchers and Cal Fire, created a map that shows which areas need fuel treatments and other preparations the most.

Probability patterns have the potential to act as guidance in future housing developments to limit growth in WUI areas. Traditionally, development begins in urbanized areas until it eventually sprawls out into less dense parts of the landscapes, and this increases fire probabilities, Moritz said.

“Our development drives our exposure and the hazard,” Moritz said.

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