The ecological memory of forest and fire 

A low flame creeps across a shallow blanket of redwood duff, swallowing sword ferns in a brief crackle of light. A few inches below ground, their rhizomes prepare to resprout after a top singe and long winter soak. For a few hours, the forest in Coastal Marin is bathed in the apricot glow of a prescribed burn. Fresh char rings the base of coast redwoods, a species dating back to the Paleocene Epoch in these Coast Miwok homelands.  

Just 30 miles north begins a network of wildfire scars that have left different marks on the landscape, and in recent memory.

The revitalizing effect of good fire

Like much of California, the compound effects of a century of large-scale fire suppression and restrictions on intentional burning – traditional stewardship practice of Indigenous people – were evident. Working as a steward on preserves that had burned in the Nuns Fire, fire ecologist Taj Katuna started to develop a more nuanced understanding of fire’s role in San Francisco North Bay Area ecosystems. “It dawned on me that some of areas where the 2017 wildfires burned, they actually had pretty good fire effects,” noted Katuna. “Oaks were regenerating, rare plants that hadn’t been seen in decades were flourishing, and wildlife habitat became more complex and abundant.”

Fire is transformative, altering ecosystems by affecting vegetation, wildlife habitat, and nutrient cycles. Every plant in the North Bay has a relationship with fire. While some plants are sensitive to or tolerate fire, other species require fire as part of their life cycle. “These ecosystems have been lacking fire for a long time. And in order to restore fire, we need to have an active relationship with it.” 

The effect of intentional fire doesn’t just reshape landscapes – it often reshapes the people who walk through them. “I don’t want to fight wildfire, but I do want to do this,” reflected the Bay Area resident. “It felt so enlightening even to just watch an intentional burn. When I finally got to work on one, I’d never felt more alive. I love how mentally and physically demanding it can be, and the trust and comradery it builds in burning as a community.”  

In 2021, Katuna dove into the Fire Forward Fellowship, a professional development program focused on planning and implementing prescribed fire for ecological benefit. But after years of writing burn plans that ran into barrier after barrier to implement, it became apparent the issue wasn’t just lack of fire or resources. “It became clear there was a real need for locally-specific prescribed fire research that could inform the way we use fire in the North Bay.” 

Investigating perceived narrow opportunities to burn 

The window of opportunity to burn is typically determined by the needs of unique ecological communities, weather and fuel moisture conditions, and the desired outcomes. But the perception of when to burn is often informed by generalized knowledge and social pressures around smoke and fire, among many factors that limit the use of prescribed fire. “When people consider the use of fire as a stewardship tool,” says Katuna, “they often say ‘it’s just too hard with all the permits and weather windows.’ This belief gets repeated so much that people take it as truth.” He believes research is a valuable tool to help answer some of these assumptions. 

“There’s a lot we still need to learn. We’re used to hearing we only have about a week or two we can burn in spring, and maybe a few weeks we can burn in fall. But we’re finding, with a little creativity, we can burn at other times as well. We just need to understand our ecosystems more,” stated Brian Peterson, interim director of Audubon Canyon Ranch’s Fire Forward program. Although much research has been done in the Southeastern states and in the Sierra Nevada, a gap exists in research in the Coastal Range that includes the Bay Area, recognized as one of the country’s six most important biodiversity hotspots. “The devil is in the details – we need more research about what works here. Better data allows us to make better decisions and get better results,” Peterson adds. 

Katuna decided the best way to address some timing questions was to develop prescribed fire research skills through a graduate program. Again, he was met with trepidation. “I spoke to professors at universities all over the West Coast. Even though most of them were excited about prescribed fire research, they doubted it was possible,” he said.

Citing the numerous barriers, permits, and reliance on fire agencies to conduct research, they advised him prescribed fire research wasn’t possible in two years. “Don’t even try,” they said. “But I had had enough experience planning burns through the Fire Forward fellowship and burning through the Good Fire Alliance to know what was possible. Through our collective support in burning together, we can get fire on the ground during opportune times. We’re nimble like that.” 

Audubon Canyon Ranch sponsors independent research 

Audubon Canyon Ranch funded Katuna’s first year of grad school at UC Berkeley where he pursued a Master of Forestry in the Stephens Fire Science Laboratory. Partnering with Audubon Canyon Ranch, Point Blue, Save the Redwoods League, CAL FIRE, and professors at UC Berkley and UC Davis, he developed a research plan to study the ecological effects of prescribed burns organized by Fire Forward.  

Katuna chose to study how prescribed fire in coast redwood forests affects tree mortality and fuel consumption. “We burned an acre of coast redwoods at Martin Griffin Preserve that winter and felt there was a lot to learn around burning in those forests,” he recalled. “I was most interested in answering research questions that would be useful to fire practitioners in the North Bay. If we’re going to go through all this effort, I want to provide us with some guidance about the effect of fire on redwoods.”  

Studies reveal increasing opportunities in seasonal nuance 

Katuna studied contemporary prescribed fire effects in coast redwood forests in Sonoma and Santa Cruz Counties. Contrary to the standard practice of using season to determine the best burn windows, the results found fuel moisture was a key driver of fuel consumption, with very few trees killed in the process.  

He also compared his findings to simulated fire effects generated using a common fire effects model, Forest Vegetation Simulator. The study revealed the need to refine the model’s ability to predict fire behavior in coast redwood forests with greater accuracy.  

Katuna’s studies contributed to new research that found an increasing trend in opportunities for prescribed fire use in Sonoma County. The study explored the relationship between long-term weather conditions and prescribed fire weather windows over a 23-year period, revealing more seasonal nuances and variation in winter and summer months.  

Sampling from multiple sites adds to growing body of research on fuel moisture 

In addition to Katuna’s fuel moisture research in Sonoma and Santa Cruz Counties, Audubon Canyon Ranch staff and others have been conducting a year-long study of leaf litter and shrub moisture in the forests and grasslands of Martin Griffin Preserve in coastal Marin County.  

Every two weeks, Adam Sawicky, a prescribed fire module leader with The Nature Conservancy, has been collecting and sorting redwood sticks of various sizes into metal tins, while Henry Inman, the preserve’s resource ecologist, has been on a similar mission in the shrublands at the edge of the preserve’s coastal prairies.  

The sample tins are baked to measure fuel moisture leading up to, during, and after a prescribed burn. The record of fuel moisture in different vegetation types over time, combined with Katuna’s recent work to help refine predictive models, will help us pinpoint opportune burn windows, achieve better fire effects, and inform timing of other stewardship practices on the preserve.

Research as an act of service 

The skills Katuna has been developing translate beyond authoring research papers and are actively being put to use by organizations across the region. His recent work includes reviewing published literature about prescribed fire smoke dynamics for Sonoma Land Trust. “I now know how to summarize and analyze academic research. I’m grateful to put that skill to use for all of us to support the work that we’re trying to get done.”  

Research and stewardship are actively evolving our understanding of how to apply fire stewardship for ecosystem and community resilience. 

• Explore our prescribed fire knowledge hub to see the growing body of scientific research, traditional ecological knowledge, and literature. 

• Check out our “Goldilocks Prescription“ article to learn more about seasonal sweet spots and other factors that affect the timing of prescribed fire in North Bay ecosystems. 

• Support our ability to sponsor local fire researchers and stewards by becoming a sustaining member.