Over the course of two days in August 2013, an unprecedented natural disaster unfolded in California’s Sierra Nevada. A small forest fire exploded into walls of flame more than 200 feet high, incinerating 90,000 acres of forest in 48 hours—an intensity nearly unequaled in the recorded history of the Sierra. Over the next three weeks, the Rim Fire doubled in size yet again and came perilously close to the giant sequoias in Yosemite National Park before it was finally extinguished. It burned so intensely that it killed many of the large, fire-adapted conifers in its path, and even sterilized the forest soil in some areas, making it difficult for seeds to germinate and the forest to regenerate.

Such intense wildfires have become increasingly common across California in the past few decades. The causes are numerous and relatively well established. A century of fire suppression by the US Forest Service, invasive pathogens that weaken or even kill mature trees, and warmer temperatures have all contributed to making forests denser, drier, and more susceptible to catastrophic fires. Unfortunately, how to manage these conditions in a way that prevents future fires from repeating the devastating trajectory of the Rim Fire is far less obvious.

John Battles. Credit: Rachel Albert

John Battles, a professor of forest ecology in the College of Natural Resources at UC Berkeley, has spent the past two decades studying the many forces threatening California’s forests. Since 2004, he has also led a collaborative project to test new ways of confronting the threat posed by future wildfires. Preliminary results from the Sierra Nevada Adaptive Resource Management Project, or SNAMP, have suggested that selectively thinning dense forests in a patchwork-like pattern is a surprisingly effective and tractable strategy to reduce—if not eliminate—the destructiveness of large fires. After seven years of meticulous measurements in two large experimental plots, the project will issue its final report later this year.

KC: How did you come to study forest ecology?

JB: Well, I grew up in Vermont, in a valley surrounded by mountains. I had always been interested in biology, so my parents assumed I would be a doctor, but I also was interested in forests. Eventually I just happened to take a class in forest ecology, and I realized that this combined my interest in biology and my interest in just being out in the forest; I’m studying something I love. And I’ve also found that ecology fits my talents, because it’s a good area for someone who’s a Jack of all trades. I felt like I was never really good at one thing, but I was okay at a lot of things.

KC: And do you see this mirrored in your students?

JB: Yes, totally. My students have a diversity of backgrounds; some are more interested in botany, some are more interested in the applied aspects of forest management, and some are interested in ecosystem ecology.

KC: Can you tell me a bit about your group’s approach to studying forests?

JB: We make a lot of relatively simple measurements. We observe the species of trees, their size and growth rates. But we look at how these things change over time, and the big challenge is to take a quantitative approach, because natural systems are very complex. When I was a young scientist, there was a criticism that field studies were not rigorous and were more like stories. The real science was done in the lab, where you’re controlling for a lot of variables that you can’t account for in the field. We aim for somewhere in the middle, where we look at well-placed field studies and natural experiments where we can measure and incorporate all of the potential variables, and this leads to complicated research designs and analysis. So people in my lab tend to like being outdoors and also tend to be unafraid of doing some pretty complicated quantitative work.

KC: How did you become involved in SNAMP?

JB: The state wanted a neutral third party of experts to evaluate the project, and they suggested it be the University of California. At the time, I was the director of the Center for Forestry, so I couldn’t not volunteer. It was probably not the best research opportunity, but it was an opportunity to bring science to bear on solving problems that are relevant to Californians.

KC: What’s the history behind the project? How did it start?

NASA's Aqua satellite captured this image of the King Fire as it raged in the Sierra Nevada forest in September, 2014. The fire threatened SNAMP field sites. Lake Tahoe is visible to the northeast of the blaze, and the California-Nevada border is shown with a thin black line. Credit: NASA Earth Observatory

JB: Well, the year SNAMP began, 2004, was one of the worst fire years in California, and this raised awareness of the risk of fire that had evolved after decades of limited timber management and continued fire suppression. The project came together when all of the agencies involved in forest management reached a consensus that the do-nothing approach to forest management in the Sierras was not working.

KC: And my understanding is that there was one management strategy in particular that the Forest Service wanted to test.

JB: Well, there was an innovative idea called SPLATs—Strategically Placed Land Area Treatments. This is the idea of treating about a third of the forest by removing some of the trees and some of the fuel from the landscape, so that if a fire came through, it would hit these treatment areas and then calm down. A fire tends to create its own momentum, but if you break up its fuel, you can turn a catastrophic fire that’s killing trees into a much less dangerous fire that doesn’t move as fast, so it doesn’t impact the forest and also isn’t a risk to people or property. And you only have to treat a third of the forest or less to get this overall effect of mitigating fires, instead of treating the entire Sierra Nevada.

KC: Why was UC Berkeley chosen by the state of California to help with monitoring the project?

JB: What sets Berkeley apart is that we have both research programs and a program that trains the practitioners—the forest managers—with experimental forests. I like to say that we have the think tank and the do tank. Adapting to global changes requires ideas and theories as well as understanding how to implement changes and how to work with the public. We have a combination of experts with a very public mission to work for the public benefit, with some of the world’s most famous forests nearby. We have the laboratory in our backyard.

KC: Now that the project is nearing its end, what have you learned? Do SPLATs work?

JB: SPLATs do work, in terms of modifying fire behavior. And they don’t need to be super carefully done. You can get a lot of value out of them even if you can’t put them in the most strategic place, and each treatment can also be different. Sometimes they remove canopy-sized trees, sometimes they remove the dense understory, and sometimes they chip and shred the downed trees. You can vary the treatments and create a diversity of habitats and still modify fire behavior.

KC: In the best case, given the changing climate, what do you hope the forests of California will look like fifty years from now?

JB: In the best case, it becomes widely accepted that a do-nothing approach is an active decision. We acknowledge that while we don’t know what will happen, doing something in a wise and careful fashion is mandatory or we’ll get very adverse effects. If we do nothing, we might see nature going crazy—catastrophic fires that link up, along with exotic pathogens that come and start wiping out entire species. So there’s a slow change in perception among scientists and managers and the public that a hands-off approach is not going to work. And the resources are there to do something.