Learning To Burn: Using Prescribed Fire To Keep California's Foothills Safe From Wildfire

A new research project at NRS reserves will characterize how prescribed fire affects oak woodlands, chaparral, and grasslands. These findings will help protect California’s most populous communities from catastrophic wildfire Image: Ethan Turpin

By Kathleen Wong, UC Natural Reserve System

A warming climate has left California at ever-increasing risk of catastrophic wildfire. Few parts of the state have been spared. Conflagrations once mostly confined to mountain communities are now devastating coastal and foothill areas from Sonoma to San Diego.

This expansion of wildfire threats has left Californians dangerously unprepared. Fire agencies and communities alike are turning to fuels reduction—eliminating the dry, dense stands of vegetation that fuel explosive wildfires—as a practical solution. Burning that vegetation in controlled, low-intensity fires is an efficient way to remove fuels from the landscape. But most fuels management research in the West has focused on high-elevation conifer forests. Far less is known about how prescribed burning affects coastal and foothill areas, where the majority of Californians live and work.

A new project led by the UC Santa Barbara Natural Reserve System aims to fill this information vacuum. Called Building Foothill Community Resilience to Wildfire with Prescribed Burns, the project will characterize how prescribed burning affects the oak woodlands, coastal shrublands, and grasslands surrounding California’s major population centers. Funded by a $1.5 million grant from the Gordon and Betty Moore Foundation, the project will provide the practical knowledge required to conduct prescribed burns safely in coastal and lowland areas and reduce wildfire risks in California’s most populous regions.

“Information from this project will contribute to the state being able to anticipate and get ready for potential catastrophic wildfire that can threaten communities,” says Marion Wittmann, Executive Director of the UC Santa Barbara Natural Reserve System and a principal investigator on the project.

“It’s really important to be able to convey how well fire works, and how landscapes recover, with prescribed burning. People worry about what that means to the landscape. They need a sense for why it might be important to burn even though burns are smoky and scary,” says UC Santa Barbara political science professor Sarah Anderson, who co-leads the project.

The NRS’s California Heartbeat Initiative established a series of climate stations on Santa Cruz Island Reserve. Data from these instruments will help atmospheric scientists develop fire weather forecasts for a range of California microclimates. Image: Jay Reti

Orienting existing research to meet a common goal

Wildfire risk is fiendishly complicated to assess. Major factors range from the type of plants (a stand of oily chaparral will burn hotter than a grassland), to weather conditions (hot and windy conditions propagate fire faster), to whether soils and plants are moist or parched and flammable. To take those factors into consideration, the program is designed to be multi-pronged and multidisciplinary.

One arm of the program will gather empirical data using methods developed by three NRS-based science programs. The NRS’s California Heartbeat Initiative (CHI) will gauge the water status and flammability of plants with ground-based measurements and remote sensing data. The Sundowner Winds Experiment (SWEX) will contribute atmospheric measurements and fire weather forecasts to ensure prescribed burns occur during safer conditions. And the prescribed burning program at Sedgwick Reserve will supply the expertise to conduct controlled burns while measuring fire behavior and effects on vegetation.

Data from each of these components will then be input into the second half of the program: a computer model used to forecast future fire scenarios. When given variables such as precipitation, temperature, windspeed, and topography, the Regional Hydro-Ecologic Simulation System (RHESSys-Fire) model can estimate how vegetation and fuel moisture patterns recover following fires. These projections help gauge risks of catastrophic fire for different possible climate futures.

The model “lets findings from each part be run forward under climate change, and that helps us think into the future,” Anderson says. “Right now we’re missing an implementation of that model that works well for these kinds of landscapes where a lot of people live.”

Because the model is designed to simulate how water, carbon, and nutrients cycle through the landscape, investigators can use it to ask specific questions that would be too expensive, laborious, or difficult to carry out in the real world. For example, the model could predict how more frequent fires would affect plant growth in chaparral or grassland. Or how more intense fires in a hotter climate could affect groundwater recharge.

This fog harp on Santa Cruz Island Reserve measures local fog moisture. This data helps scientists understand how local climate conditions affect the flammability of plants. Image: Jay Reti

A sum greater than its parts

Each of these project components will supply a unique piece of the information needed by the project as a whole. For example, the California Heartbeat Initiative established an array of microclimate stations on the NRS’s Santa Cruz Island Reserve. Led by UC Berkeley plant physiologist Todd Dawson, this portion of the project will analyze how site characteristics such as slope and fog exposure affect soil conditions and plant health. The island’s isolation, size, and varied terrain make it ideal for studying microclimate conditions ranging from desert dry to drenched in ocean fog. “It’s far from the chaos of humans and pollution, lights, and traffic that can interfere with measurements,” says Santa Cruz Island Reserve director Jay Reti.

The program will enable additional stations capable of providing live, open-access weather data to be installed on the island. This high-resolution climate data, together with existing CHI datasets from nearby areas, will enable researchers to observe and simulate conditions analogous to a multitude of locales on the mainland. SWEX climate scientists Leila Carvalho and Charles Jones will use this information to refine their predictions of fire weather to a scale of 1 square kilometer or smaller.

Thanks to the new project, Carvalho and Jones will also be able to install a flux tower at Sedgwick Reserve to collect carbon dioxide and water vapor data throughout the year. These data will enable the atmospheric scientists to provide short-term fire weather forecasts for the region. They will also be able to generate weather predictions to help ensure prescribed burns are held during optimal weather conditions.

Media artist Ethan Turpin documented a November 2022 prescribed burn at Sedgwick Reserve as part of his Burn Cycle Project (https://burncycleproject.com). The project uses multimedia experiences to improve public understanding of wildfire risks and mitigation methods. Turpin places cameras in fireproof boxes like the one shown here to record flames as they sweep past. He uses icepacks (or in a pinch bags of frozen peas and pineapple chunks) to keep his camera equipment cool. Image: Ethan Turpin

Adding value to Sedgwick’s prescribed burn program

Meanwhile, the project will enable scientists to glean even more data from the ongoing prescribed burn program at Sedgwick Reserve. Led by Frank Davis, director of the La Kretz Center for Research at Sedgwick Reserve, the program has already been conducting burns in oak savanna, grassland, and sage scrub in and around the reserve. It measures vegetation conditions before and after burns, and deploys instruments in burn areas to measure fire intensity. The new grant will augment the project by funding live fuel moisture measurements in reserve vegetation. This characteristic, which gauges the amount of water in plant tissues, is closely correlated to fire risk.

“We’re trying to understand to what extent fire is a tool for not just public safety, but also to promote resilience to climate change, to promote certain kinds of biodiversity. Are you promoting plant diversity? How do wildlife and tick populations respond? What are the impacts on oaks and their growth patterns?” Davis says.

The Sedgwick prescribed burning program partnered with The Nature Conservancy’s Prescribed Fire Training Exchanges (TREX) to conduct its November 2022 burn. TREX gives fire professionals hands-on experience managing prescribed burns. At Sedgwick, scientists are monitoring environmental and vegetation conditions prior to and during the burns, and track how habitats rebound afterward. Image: Ethan Turpin

The benefits of reserve work

For Davis, burning at an NRS reserve like Sedgwick offers many advantages. “Because it’s a large reserve, we have the ability to do prescribed burning at a scale that’s reasonably large, to really look at fire behavior realistically. It gets us a chance to monitor over the long term in a way that you couldn’t if you were working in other areas. We also just have a great baseline of information to begin with in terms of pre-burn conditions.”

The prescribed burn project brings with it a variety of additional stakeholders. These include Santa Ynez Valley residents, fire professionals from several agencies, and the Santa Ynez Band of Chumash Indians. The Chumash managed California landscapes with fire for thousands of years, but lost much of that knowledge after European colonization. The tribe now seeks to learn how plants culturally significant for medicine, basketry, building, and other uses respond to different burning regimes.

A stand of oak woodland at Sedgwick Reserve just prior to a November 2022 prescribed burn. Image: Ethan Turpin

Low-intensity prescribed fire consumes the dry grass and brush, but leaves the oaks unscathed. Image: Ethan Turpin

The prescribed burn has dramatically reduced fire fuels on the landscape, leaving behind blackened soils and the skeletons of burned shrubs, but also healthy oaks. Image: Ethan Turpin

Fuels treatment inequalities

However, understanding the mechanics of prescribed burning is only half the battle. A public educated to fear fire from childhood (remember Smokey the Bear?) isn’t as familiar with the seemingly paradoxical use of flame to reduce wildfire risks.

Anderson’s previous research has shown that the US Forest Service is more likely to conduct fuels management projects in areas that burned by recent wildfires. This is because communities that have lived through the terror and uncertainty of uncontrolled blazes recognize the value of removing standing fuels.

“Those communities for whom wildfire becomes concrete demand action. But now we’re managing for the past. They have reduced risk relative to a community that’s just not paying attention because they haven’t had a wildfire,” she says.

Other research has shown that communities that receive landcape-scale fuels reduction projects tend to be wealthier and whiter. Taken together, these findings reveal serious inequities in where wildfire risk reduction efforts are applied.

Modeling better fuels management

This is where the RHESSys-Fire model shines. It can show the relative risks of wildfire in chaparral and oak woodland ecosystems under different climate scenarios. It can model the results of more frequent or very infrequent fuels reduction efforts, and help land managers identify schedules for vegetation management able to balance fire risk reduction and habitat health.

“We know there’s inequity, but we don’t know what the consequences of that inequity are for carbon storage on the landscape, for water supply and quality, and for fire risk,” Anderson says. “We need the model to more accurately say how this inequity affects these outcomes we’re trying to actually manage. Where else should the Forest Service or other land managers be thinking about doing its fuels reduction projects? What do different areas lose or gain?”

Toward public acceptance

The more is learned about the details and benefits of fuels reduction efforts, the researchers say, the more likely Californians are to initiate fire safety measures at a landscape scale.

“I’m hoping that through this project, people will get comfortable with prescribed burning as a tool on the landscape, and improve the management of land for wildlife and people,” a confident Wittmann says. “We can manage our lands in a way that reduces catastrophic wildfires.”

Learning to burn: using prescribed fire to keep California’s foothills safe from wildfire