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Posts Tagged: Scott Stephens
Lessons on wildfire resilience from a 4,000-acre forest lab
In his years managing California woodlands, Rob York has come up with a few quick and easy ways to gauge whether a forest is prepared for wildfire.
“The first question I like to ask is, ‘Can you run through the forest?'” York says.
York, an assistant cooperative extension specialist and adjunct associate professor of forestry at UC Berkeley, poses the question while standing in a grove of pine trees during a tour of Blodgett Forest Research Station, a 4,000-acre experimental forest in the northern Sierra Nevada. While fire suppression has allowed many of California's forests to grow thick and dense, this patch of forest is one you could actually run through: The area is punctuated by large trees spaced a few meters apart, separated by a smooth carpet of dried pine needles.
“The idea is, if it doesn't have a lot of buildup of surface fuel on the ground — sticks and logs — you should be able to run through it,” York adds. “Looking through this forest, I might have to jump over that log, but, generally, I could take a jog through it.”
For more than 50 years, York and other Berkeley forestry researchers have used Blodgett as a living laboratory to study how different land management treatments — including prescribed burning, restoration thinning and timber harvesting — can reduce the risk of severe wildfire and improve a forest's resilience to the impacts of climate change. In addition to research, Blodgett regularly hosts workshops to demonstrate different land management techniques to landowners.
After another year of record-breaking wildfires in California, the work at Blodgett is more critical than ever, and state and federal agencies are motivated to enact more effective forest management practices. In 2020, the state and the U.S. National Forest Service jointly committed to managing 1 million acres of California forests a year, and last month the Biden administration pledged billions in new federal funding to reduce wildfire risk in the state.
“[Blodgett] was really designed to eventually demonstrate land management alternatives and offer a glimpse into how they might look at bigger scales,” York said.
Experimenting with fire
Blodgett Forest is “pretty representative of millions of acres of Sierra mixed conifer forest,” said Ariel Roughton, a research stations manager at Berkeley Forests. After the majority of its trees were logged in the early 1900s, the forest was donated to Berkeley in the 1930s with the intent that it would be used to study sustainable timber production. Aside from a few old relics that survived early logging, the majority of the trees are regrowth and approximately 100 years old.
“Back then, people thought, ‘Why would you ever want to use fire for land management?' They wanted to grow trees, they want to grow timber. The idea of seeing black and char was literally off the scale,” said Scott Stephens, a professor of forest science and co-director of Berkeley Forests. “It's amazing that just a few decades ago, researchers didn't have the opportunity to do the work that Rob and Ariel and others are doing up here now.”
In the open, airy tract of forest that York could easily jog through, blackened scorch marks extend 10 to 15 feet up the trunk of each tree. Ecologists believe that before European colonization, these forests experienced fire once every 10 years or less, leading to open forest structures very similar to this one. Here, two years ago, Roughton, York and their colleagues conducted a prescribed burn to remove excess fuel from the ground and reduce the risk of wildfire.
“I think it's important to remember that nature hasn't taken its course without a lot of human intervention since the last glaciation, because there was strong Indigenous burning here,” said John Battles, a professor of forest ecology at Berkeley. “There has always been intense human stewardship of one sort or another.”
While there are forest management strategies that can be effective on a shorter time scale, it usually takes at least a few separate treatments over the course of a few years to successfully restore a forest and reduce its wildfire risk, York explains.
“It can be a challenge to get to the forest structure that we want,” York says. “It takes a lot of time, and it takes a lot of investment.”
Climate change is also narrowing the annual windows of time when conditions are best for prescribed burning, limiting when and how often foresters can safely burn. Hot, dry conditions usually make prescribed burning too risky during the summer, while rain and snow in the winter can leave the forest too wet and damp for fire to burn. However, research at Blodgett is showing that, with the right management decisions, prescribed burning during the winter can be made more viable.
“Because of timber harvests that removed some of the canopy and subsequent treatments to remove the ladder fuel, we now have more light hitting the ground, and it dries out faster,” Roughton said. “We've gotten to the point out here where we're able to burn more easily because of our past management actions.”
Friends of the forest
While York likes to imagine running through the trees, Battles has a slightly different metric for evaluating the health of a forest.
“You need to be able to run through the woods,” Battles said. “But I also want to see all six of my friends as I do my run.”
Battles' friends are the six tree species that make up the Sierra mixed conifer forest: oak, ponderosa pine, sugar pine, white fir, Douglas fir and incense cedar. Fire suppression — and the dense, overgrown forest structures that can result — often favor the survival of some of these species over others, leading to forests that are dominated by just one or two species. This lack of biodiversity can make the forest, as a whole, less resilient to stressors like bark beetles or tree pathogens, which often target some of these species, but not others.
According to Battles, the open structure and frequent fire at this tract of Blodgett has allowed all six of his friends to flourish.
“I see my friend, ponderosa pine, which you don't see as frequently in the unburned forest because it's shade intolerant — it needs light. I see oak, and it also requires fire to get a lot of the oaks,” Battles said. “I see all six of my friends all here, and you only see them when you have management like this.”
Over the past 20 years, research has shown that prescribed burning and mechanical thinning with tools like the masticator can also benefit soil quality and water availability, while having no significantly negative impacts on forest ecosystems. While burning or otherwise removing plants and trees can release carbon dioxide into the atmosphere, which accelerates the impacts of climate change, reducing the risk of severe wildfire can help maintain the whole forest for long-term carbon storage.
However, applying these techniques across 33 million acres of California forestland remains a monumental task. Prescribed burning requires a great deal of expertise and is also limited by weather conditions and air quality regulations. Meanwhile, mechanical tree thinning can be costly, and unlike timber harvesting, it does not generate any revenue for landowners — though Berkeley researchers have suggested that creating a market for small trees and other woody biomass could help offset the cost while limiting carbon emissions.
“Fire used to be so common in this system, and that's no different than in most forests in California. But, when you take it out for that long, you begin this transformation,” Stephens said. “That's why we have to get both public and private entities together to come up with a philosophy to be able to move forward on this. Blodgett is 4,000 acres — that's interesting, but it doesn't really address the needs of the state. We always hope that our work shows people what's possible and then enables them to continue it.”
Forest management can help giant sequoias and coastal redwoods survive
In 2020, 9,000 fires scorched more than 4 million acres of California, a record-breaking year, reported Alejandra Borunda in National Geographic. Fires burned through homes and oak forests, grasslands and pines — and also through patches of giant sequoias and coast redwoods, respectively the most massive and the tallest trees on earth.
Giant sequoias are not the oldest living trees, but some have been growing in Sierra Nevada forests for more than 3,200 years. They are found in 68 groves on the Sierra's western flank. The state's redwood forests grow in a narrow strip along the coast of Northern California and Southern Oregon.
The 2020 fires burned through about 16,000 acres of sequoia groves, about a third of their total area. In redwood forests of the Santa Cruz Mountains, 40,000 acres burned.
But because redwoods are well-adapted to fire, they'll likely recover pretty quickly, said Scott Stephens, a UC Berkeley fire scientist. “In some ways, this fire could make redwoods more dominant in the landscape," he said, because other trees — like the hardwoods or Douglas firs that crowded the local forests — died outright in the burns.
However, scientists are concerned one cause of the fires, climate change, could have additional impacts on these natural treasures.
Since the mid-1800s, temperatures in the western U.S. have increased by 1.6 degrees Fahrenheit. Fog banks are fading in coast redwood territory, and snows are less consistent in the Sierras. The changes leave redwoods and sequoias without their preferred climate conditions.
The most responsible thing to do now, Stephens said, is to “take the opportunity that has been handed to us,” and make a plan to go back in and burn again—soon, within the next few years.
UC Cooperative Extension forestry advisor Lenya Quinn-Davidson agrees that California must manage fire to help the trees survive. Tree-ring records show that humans have influenced the fire regime for better and worse as long as they've been in these forests.
“The empowering message there is, human management can actually override the effects of climate in a fire contest,” Quinn-Davidson said. “It's not just a climate story. We can't just throw in the towel, feel overwhelmed, and tell ourselves these trees are done for. That's not true!”
North Coast forests are more dense and dry, fueling fires
Five of California's six largest fires have occurred in 2020, reported Julie Cart in CalMatters.
Quinn-Davidson is based in Humboldt County, with typically rainy, foggy redwood forests. However, she said, the forests don't resemble their former state.
"They are suffering from the same things that the rest of the state forests are. They are poorly managed and have fuels buildup," Quinn-Davidson said.
Redwood and pine forests are many times more dense than at any time in their history.
"We are now entering a new regime, the climate is changing and we are seeing drier conditions and we are seeing a longer fire season. We are not getting that fall precipitation," she said.
The state's 2018 Fourth Climate Assessment included dire predictions for the North Coast: “Future wildfire projections suggest a longer fire season, an increase in wildfire frequency, and an expansion of the area susceptible to fire.”
Average annual maximum temperatures in Mendocino, Humboldt, Del Norte, Lake, Trinity and Siskiyou Counties could increase by as much as 9 degrees through the end of the century, the report concluded.
The fog that reliably blankets the North Coast is dissipating. Research from UC Berkeley found that fog frequency has declined by a third compared with a century ago.
“Even here in Humboldt County — we are right on the ocean, basically in a rainforest — people are starting to look around and say, ‘Is my house ready for a wildfire?' I'm hearing those conversations,” Quinn-Davidson said.
UC ANR experts suggest ways to ease California's fire crisis
Three news articles over the last weekend shared comments from UC Agriculture and Natural Resource's experts about forest management practices that can help reduced the catastrophic wildfires being experiences in the West.
Prescribed burns and management change fire behavior
Shaver Lake forest historian Jared Dahl Aldern tweeted that, when the high-intensity Creek Fire arrived at the Shaver Lake forestlands, it turned into a low-intensity “surface fire,” which does not threaten the bigger and older trees. “The fire comes up to @SCE land,” tweeted Aldern, “drops to the ground, and stays out of the tree crowns.”
Whatever happens to Shaver Lake, says University of California Cooperative Extension specialist Rob York, “There are lots of cases in the scientific literature of prescribed burns having changed fire behavior.”
The image below shows a “shaded fuel break,” consisting of selectively-thinned forest surrounded on both sides by dense forest. “The strip of forest may change fire behavior in the treated area,” said York, “but not on either side.
Forbes, Sept. 13, 2010
Michael Shellenberger
Millions of dead trees fueling unprecedented firestorms in the Sierra Nevada
“I don't want to be alarmist. But I think the conditions are there,” said Scott Stephens, a UC Berkeley professor of fire science and lead author of a 2018 paper that raised the specter of future mass forest fires as intense as the Dresden, Germany, and Tokyo firebombings.
“As those [trees] continue to fall, the physics of it are unchanged. If you have dead and downed logs … the fires described in warfare are possible.”
A combination of prescribed fire, restoration thinning and making rural communities more fire resistant are needed, Stephens said.
“If we don't come out of this year focused on that and try to move forward, I just don't know if there's much hope,” he said. “I'm always hopeful. But I'm getting tired.”
Los Angeles Times, Sept. 13, 2020
Bettina Boxall
Results of long-time fire suppression
Perhaps the most present term in news articles as one of the main causes for fires getting so big so fast is fire suppression, which has resulted in a lack of fire for more than a century.
In the 1920s, this idea of suppressing wildfires grew even more when the Forest Service decided intentional burning was a bad idea. In 1924 a Siskiyou National Forest Supervisor said the ‘“Brushy Hell' of shrublands must be protected for the benefit of future timberland succession, ‘so leave them alone.'”
“The Forest Service said it ruins forests, it was bad forest management,” said Kocher. “Then in 1924, California followed suit and said it was not legal to burn forests on purpose.”
Kocher says this idea of letting trees grow and not letting forests burn naturally every decade wasn't this malicious idea either.
“They would have thought, ‘Oh, we're doing this great work where we're leaving all these extra trees for people to use for timber moving forward,'” she said. “I don't think those early foresters ever could have foreseen how fire could get away from them.”
Capitol Public Radio, Sept. 12, 2020
Ezra David Romero
UCCE experts provide scientific fire information to media
The raging fires sparked during August have raised the visibility of UC fire scientists, who provide critical information to state and national media. Below are a sampling of stories and comments offered by UC Cooperative Extension experts:
Forest management needed
“When we started suppressing fires 100 years ago all the time, we actually allowed a huge buildup of fuels and debris,” said UC Cooperative Extension forest advisor Susie Kocher, who is based in the Lake Tahoe region.
She is an advocate for requiring residents to clean up the extra fuel — grasses, trees, shrubs and clutter — around their homes, making them fire ready, and for more prescribed burns.
“There's a need for more frequent, low-severity fire across the landscape, so that we wouldn't have quite so much explosion in the burning in the fields that we have currently,” Kocher said.
In August, the state and federal government agreed to clean up 1 million acres by 2025, with practices such as prescribed burns. Part of that agreement also included a commitment to create a 20-year plan by next year to prioritize areas for forest-thinning. But even this plan is sliver of what's needed to protect California from devastating future wildfires.
“I think it's a good indication they're paying attention now and that we're moving in the right direction,” said Michael Jones a UC Cooperative Extension forestry advisor in Mendocino, Lake and Sonoma counties. “My hope is that once we start with a million, then it's really easy to scale up to multiple millions.”
Capitol Public Radio, Sept. 3, 2020Taking steps to reduce fire danger
“There are things that we can and should be doing to address the fire problem and fire risk in California, and to get ahead of it, and to make ourselves more resilient,” said Lenya Quinn-Davidson, a fire advisor with the University of California Cooperative Extension and director of the Northern California Prescribed Fire Council.
Quinn-Davidson said she was encouraged when California Gov. Gavin Newsom and U.S. Forest Service officials announced an agreement this month on a joint strategy to reduce wildfire risks.
“We need more coordination and more collaboration among all of the different groups who work on these issues,” Quinn-Davidson said. “The number one thing we need is more coordinated vision around what fire is going to look like in California, how people can live with fire.”
Arizona Central, Aug. 28, 2020
What's at stake
“Every part of California is receptive to wildfire,” said Yana Valachovic, a UC Cooperative Extension forestry advisor on the North Coast. “Especially in a year like this, when we had a pretty dry winter and spring, so a lot of the state is in drought conditions.”
Sacramento Bee, Aug. 27, 2020
Fires are getting worse
"They are certainly getting worse over time," said Susan Kocher, a forestry advisor at the University of California-Cooperative Extension Central Sierra. "We burned fewer acres in wildfires in 2019 than 2018, but overall, yes, the trend is progressing to burning more and more acres at high severity over time and affecting more people through evacuations and damages to homes and communities."
Yana Valachovic, a forest advisor and county director at University of California Cooperative Extension–Humboldt and Del Norte counties, said that 100 years of fire suppression is catching up to the state as well. Valachovic said before California was settled by white pioneers around the gold rush in the 1850s, Native Americans frequently used fire as a tool —for example, to clean out an infestation of bugs in acorns.
"Fire can be really important for stimulating biodiversity and creating more food sources," Valachovic said. "After years of suppressing those fires, now we get an ignition, whether human-caused or lightning-caused or power lines down, and you have an accumulation of materials that have accumulated over various time periods, but the quantity of fuel is substantially greater than it was historically."
Salon, Aug. 25
Firefighting priorities
“At the statewide level, we do get into this mode where we start wondering where the biggest loss is going to be, what's the highest priority, and that is where the resources are going to go,” said Lenya Quinn-Davidson, a fire specialist with the UC Cooperative Extension.
Los Angeles Times, Aug. 24, 2020
Take action
Q: Beyond widely accepted reasons for wildfires growing in size, severity, and frequency, why hasn't California made more progress in slowing the trend?
Lenya Quinn-Davidson: Our fire management and our land management haven't kept pace with the scientific understanding we have of fire in California. There's this fear of active land management – prescribed burning, thinning – that sometimes gets in the way of us making good choices. If we're not protecting the resources we care about and we're not taking action, then we will continue to lose them to big fires.
Bill Stewart: Many of the fires around the greater Bay Area are in areas that didn't burn 30 years ago because they were cattle ranches. They had cattle on them, and that helped reduce fuels. Now those areas have turned into parks or 5- and 10-acre residential lots. So much development has been about what's aesthetically pleasing, so we've ended up with a landscape that, during hot and dry seasons, there's a lot more fuel and it becomes a much riskier situation.
Q: The era of megafires in California has been decades in the making. How can public agencies begin to counter that over the next few years?
Quinn-Davidson: We need to create a more robust and sustainable fire workforce. Right now, they're so beat down at the end of fire season – especially as fire season is getting longer in California – that there's basically no capacity the rest of the year to do any of the proactive stuff we need to be doing. So we need to create more jobs, and those jobs need to be dedicated to fire management and land management.
Christian Science Monitor, Aug. 24, 2020
Historical fire suppression
“We have put out fires for 100 years. Now we are paying the price,” said Scott Stephens, a professor of fire science at UC Berkeley. “It will take a while to make these forests healthy again. But it's absolutely possible.”
Stephens, the UC fire scientist, estimates that before the Gold Rush, roughly 4.5 million acres a year in California burned. By the 1950s and 1960s, that was down to about 250,000 acres a year. In recent years, it has approached 2 million acres a year.
San Jose Mercury News, Aug 23, 2020
Limited firefighting resources
At the statewide level, we do get into this mode where we start wondering where the biggest loss is going to be, what's the highest priority, and that is where the resources are going to go,” said Lenya Quinn-Davidson, a fire expert with the University of California Cooperative Extension.
Los Angeles Times, Aug. 22, 2020
Smoke impact on fresh produce
According to a 2018 preliminary UC Cooperative Extension Sonoma study, smoke from 2017 fires had little impact on local Sonoma County produce.
Based on preliminary findings, "...produce safety was not significantly affected by the fires and may be mitigated by washing produce."
The Californian, August 21, 2020
