The Eaton Fire in California killed 19 people and destroyed more than 9,000 homes and businesses. BU researcher Jennifer Bhatnagar is studying how forests, particularly in urban areas, can become more resilient in an era of increasing wildfire risk. Photo by Ringo Chiu/SOPA Images/Sipa USA via AP Images

Wildfire

How Scientists Are Helping Restore Forests After a Wildfire

Boston University biologist Jennifer Bhatnagar is studying ways to help California and other states recover from—and become more resilient to—catastrophic fires

Wildfires are getting bigger, more frequent, and increasingly costly—the US Geological Survey puts the annual toll of damages and recovery at $424 billion. One of the most heavily impacted parts of the country is California, with last year’s catastrophic Los Angeles fires alone killing more than 30 and costing $60 billion.

It’s a devastation Boston University forest microbial ecologist Jennifer Bhatnagar has seen firsthand as part of her research. She’s been studying wildfire impact on northern California since the summer of 2023—a year of more than 7,000 wildfires in the state. On one of her first visits then, she traversed charred, barren hillsides, examining the hot soil, collecting samples, and speaking with residents.

“There were black trees everywhere, little resprouting of trees, little new vegetation,” says Bhatnagar, a BU College of Arts & Sciences associate professor of biology.

Over the past three years, Bhatnagar and her team have explored how wildfire, urbanization, and ecological restoration shape forest recovery in northern California—and how forests, especially those close to where people make their homes, can become more resilient in a future where severe wildfires are increasingly common.

“We don’t fully understand how urban ecosystems are affected by climate-induced changes like intensifying wildfires,” she says. “This means that we can’t make informed decisions about how to manage and restore urban lands, including residential lands, after fire. This research is filling these knowledge gaps directly.”

In addition to seeing how urban and suburban woodlands respond to and recover from wildfires, the team has also been looking for solutions.

“We are testing some novel restoration techniques to assist in that recovery,” says Bhatnagar, director of CAS’ Biogeoscience Graduate Program. “What we learn here will inform ecologists and land managers in California and beyond, in regions where the wildfire-urban interface is spreading.”

Looking Beneath the Forest Surface

Bhatnagar’s research has long been focused not on forests themselves—but what lies beneath them. She’s an expert on soil microbiomes: complex communities of bacteria and fungi that recycle nutrients, support plant health, and help determine how forests respond to environmental change.

“They’re the hidden engineers of the forest,” she says.

Bhatnagar first studied forest microbiomes in northern California as a National Oceanic and Atmospheric Administration postdoctoral fellow. But the impact of wildfires wasn’t a central part of her research until she met Napa Valley landowners Frank Naeymi-Rad and Theresa Kepic. The couple, both Midwesterners, had purchased 18.5 acres in Napa and were interested in understanding the ecology of their properties and exploring whether truffles—a highly prized and valuable crop—might be cultivated there. They were also eager to understand how to steward the land responsibly. That’s where Bhatnagar came in.

“We would ask a gardener, ‘What can you grow here? Why is this happening?’ They would say, ‘You can grow anything in California.’ But we were really trying to understand why,” Kepic says. They invited Bhatnagar—who they’d connected with after a chance meeting with her husband—to give them a different perspective.

As Bhatnagar walked their land and the surrounding region, her questions extended far beyond fungi. Why were some areas recovering from wildfires more quickly than others? Why were bay and maple trees regrowing, but oaks and redwoods were not? Why was one burnt area suddenly covered with non-native grass? And, perhaps most importantly, what kinds of restoration would help these landscapes thrive decades into the future?

“Visiting northern California and just walking through the burns, we learn so much about the ecology of the place,” Bhatnagar says. “That is where the scientific inspiration comes from.”

The initial conversation about mushrooms grew into something much bigger, and with support from Naeymi-Rad and Kepic’s Ecotechnology and Landscape Restoration Research Fund, Bhatnagar and her team launched a project studying wildfires and forest recovery across northern California.

Wildfire Research Shaped by the Community

To kick off the research, Bhatnagar spent months meeting with people whose lives and livelihoods depended on the region’s land. She consulted fire officials, restoration practitioners, land managers, landscape architects, fellow researchers, students, and residents. “They taught me things I could never learn in a written report,” she says. “It was a community effort.” Bhatnagar and her team’s work has since spanned Napa and Sonoma counties, taking in regional and state parks, vineyards, and individual properties.

Residents had clear preferences for what they wanted to regrow on the land, Bhatnagar says, and community priorities did not always align with conventional restoration practices. For example, researchers favor evergreen Douglas fir or pine trees—the “model organism for the study of plant-microbial interactions in forests,” she says—but locals wanted native oaks and redwoods, favoring species that were both fire resistant and culturally meaningful.

“That changed how we thought about the science,” Bhatnagar says. “We had to rethink how to test some scientific theories of forest recovery, using species that the community wanted.”

Today, her team is pursuing two interconnected lines of research.

One asks how urban development influences recovery after wildfire. As roads, neighborhoods, and infrastructure spread into natural landscapes, forests become fragmented. Those areas are often hotter, drier, and more polluted than intact forests, changing conditions both above and below ground.

“We’re interested to know how lands recover from wildfire when there are houses and streets and population,” Bhatnagar says. “Our hypothesis is that being urban makes it harder to recover. You don’t have as much water in your soil. You have higher temperatures in your soil. You have higher pollution.”

One of her collaborators on the project is landscape architect María Villalobos Hernandez of the Illinois Institute of Technology’s School of Architecture. She encouraged the team to think beyond forest recovery alone, asking not just how forests respond to wildfire, but also how post-fire landscapes can foster both ecological and human resilience.

Bhatnagar’s second line of research explores how people can actively restore forests after a wildfire.

Inspired in part by conversations with Kepic about the Miyawaki method of forestry developed in Japan, Bhatnagar’s team established a series of densely planted “mini forests”—4-square-meter plots—using native California species. They have since planted thousands of acorns alongside other native plants selected for their ecological resilience, cultural significance, and ability to thrive in a hotter, drier climate.

Recovery and Restoration: Living Classrooms for Local Students

Bhatnagar also regularly returns to Naeymi-Rad and Kepic’s land to help monitor vegetation, collect environmental DNA, analyze soil microbes, and measure how different restoration strategies influence recovery over time. She and her team are joined by local college and high school students. Together, they are turning restoration sites on the couple’s land into living classrooms for research, design, and hands-on learning.

Although Naeymi-Rad and Kepic were forced to abandon their plan for truffles—though morel mushrooms have flourished—the project that grew from their first conversations with Bhatnagar has had unexpected, long-lasting benefits.

“Our properties are laboratories for students,” Naeymi-Rad says. “Seeing those students out in the field, asking questions and making discoveries, is incredibly exciting. That’s been our gift—to empower scientists to build the curriculum of the next generation.”

For Bhatnagar and her collaborators, the work is far from finished. Each visit raises new questions—and new possibilities for living with fire in a warming world.