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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.

Blodgett Forest Research Station is a 4,000-acre experimental forest in the northern Sierra Nevada. All photos by Evett Kilmartin

“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.

Though prescribed burning was once banned at Blodgett, it is now one of the primary tools that researchers use to reduce wildfire risk and maintain the biodiversity of the forest.

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.

Kane Russell, interim forest manager at Blodgett, holds two drip torches after demonstrating how they are used to start prescribed burns.
The forest is currently divided into a patchwork of tracts, each having received a different series of treatments since active management began in the 1950s and 1960s. And while fire suppression was once the policy at Blodgett — early fire ecologist Harold Biswell was even banned from using prescribed burns out of fear that they would interfere with the timber harvest — fire is now one of the primary tools that Blodgett researchers use to maintain biodiversity and reduce the risk of severe wildfire.

“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.”

Rob York says a healthy forest is one that you can run through.
According to the researchers, it took 15 to 20 years of active management, followed by regular maintenance, to get the forest tract to this state. Over the years, they have worked to achieve the open forest structure by harvesting some of the bigger trees for timber, but leaving the largest behind. They have also used a machine called a masticator to chip up smaller trees and conducted regular prescribed burns.

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.”

Using machines to manually remove small trees and underbrush poses fewer risks than prescribed burns, but often comes at a much higher cost.

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.

John Battles likes to see a mixture of all six tree species that make up the Sierra mixed conifer forest.

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.”

Scott Stephens hopes the work at Blodgett will serve as a model for forest management in the rest of the state.
Posted on Tuesday, February 1, 2022 at 11:53 AM
  • Author: Kara Manke, UC Berkeley
Focus Area Tags: Environment

To reduce wildfire risk, forestland owners can do winter controlled burns, says UCCE expert

When conditions are right, winter can be a good time to conduct prescribed burns for forest management, says Rob York, UC Cooperative Extension forestry specialist.

“A huge issue we have in California is fire severity. We know from research that prescribed fire can be a very good tool for reducing fire severity,” York said. “For forest landowners or foresters who want to do their own prescribed burning, winter burning can be a good entry point.”

York is based at the UC Blodgett Forest Research Station in Georgetown, where he developed a series of eight short videos demonstrating how fire can be used on landscapes during the colder months. The videos feature controlled fires conducted at the station on Dec. 6 and 9, 2020. More videos in this series will be posted during the upcoming year.

Winter prescribed burns allow landowners to reduce fuels with low risk.

Among the factors covered in the videos are climatic conditions and site selection for winter burning.

Climatic conditions

Wet or snowy weather in the fall may seem to shut the window for prescribed burning, but York said often the snow melts away and fuels dry out enough to do a winter burn.

“The idea is to be ready when the fuels dry out,” he said. Thinning trees and masticating underbrush are ways to prepare the forest for a burn.

When selecting the day of the fire, relative humidity, temperature and wind speed and direction are important considerations.

“Relative humidity should be low. You want the cloud cover to be very low. A sunny day helps dry out the fuel,” York said. “In the winter, you want that drying and heating power of the sun to help the fuel be consumed.”

Site selection

Among the factors to consider in selecting locations for winter burns is the aspect. The sun's warmth is optimized on south-facing slopes.

“That's what we're looking for,” York said. “Relatively small areas that are burnable.”

An open canopy allows sunlight to dry out the understory vegetation and surface fuels, enabling successful winter burns.

Vegetation type also weighs into winter burning decisions.

“Bear clover plus pine needles make this feasible, including conditions on the wetter side when you might not otherwise be able to burn, you can burn,” York said. “If you can encourage bear clover and pine needles, you can encourage more opportunities for low density burns, which I think do a great job to maintain low fire hazard.”

Find the complete series on the UC Forestry and Range YouTube channel (https://www.youtube.com/user/UCExtensionForestry) in the playlist titled Winter Prescribed Burning

UC Agriculture and Natural Resources brings the power of UC to all 58 counties. Through research and Cooperative Extension in agriculture, natural resources, nutrition, economic and youth development, our mission is to improve the lives of all Californians. Learn more at ucanr.edu.

Posted on Friday, February 19, 2021 at 11:26 AM
Tags: prescribed burn (6), Rob York (6), wildfire (167)
Focus Area Tags: Natural Resources

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.

A shaded fire break within a dense forest. (Photo: Rob York)

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

Posted on Monday, September 14, 2020 at 10:11 AM
Tags: Rob York (6), Scott Stephens (21), wildfire (167)
Focus Area Tags: Natural Resources

Catastrophic wildfires and climate change lead to growing acceptance of ‘pyrosilviculture’

For millennia, fires periodically burned through California forests, thinning trees, reducing shrubbery and clearing out downed branches and debris. Without periodic fire, the forests became more dense, with spaces between large trees filling in with a thick carpet of duff, seedlings and shrubs.

As a result, today's forests are prone to more intense and damaging fires, like the Rim Fire, King Fire, and — most recently — the Camp Fire in Butte County. These fires are burning with unprecedented severity and speed, threatening large swaths of forest, towns, and even urban areas.

The Camp Fire in Butte County on Nov. 8, 2018. (Photo: NASA)

Using fire as part of forest management is not a new concept. Native Americans were known to burn brush to open up hunting grounds and clear shrubbery for gathering. Decades ago, iconic Berkeley forestry professor Harold Biswell said, “Fire in the Sierra Nevada is as important as rain.”

Competing forces, however, pushed foresters and fire officials toward fire prevention and suppression, particularly the cataclysmic fires of the early 20th century that leveled entire towns and left dozens of residents and firefighters dead. The fear of out-of-control blazes and the perceived damage to timber resources launched a war on fire that has lasted a hundred years. Some forest managers are urgently trying to negotiate a truce.

Making peace with fire and turning it into a useful tool, rather than a raging threat, was the objective of an October meeting in Shaver Lake of UC Cooperative Extension forestry and natural resources scientists, Southern California Edison forest managers, CALFIRE officials and U.S. Forest Service representatives.

Participants in the pyrosilviculture training gather at a recent prescribed burn site near Shaver Lake.

The event also raised awareness of “pyrosilviculture,” a new forest management term coined by UC fire scientist Rob York to emphasize the importance of fire in silviculture, the management of forests for wood.

Forests have myriad benefits – recreational, environmental and economic. Nature lovers value the whisper of pine trees in the wind and green shade over hiking trails and ski slopes. Owls, bears, deer and other wildlife make their homes among firs, pines, oaks and cedars. Forests stabilize mountain slopes, which store water as snow for agriculture and drinking. People build their homes, businesses and schools out of the planks and boards cut from the straight, soft wood of conifer trees.

The value of California forest products was about $429 million in 2017, according to the USDA. Because fires can damage and destroy trees, the timber industry has historically been reluctant to use fire as a tool. That's changing.

“Fire is such an important ecological process, you can't manage for timber without fire,” York said.

York is the manager of the Blodgett Forest Research Station, UC Berkeley's 4,000-acre mixed conifer and oak forest near Georgetown where researchers study forest management practices for increasing timber yield while taking advantage of fire to enhance forest health and make forest stands more resilient to wildfire.

Controlled burning can be used to treat fuels and reverse these trends, but it has been inhibited by a number of barriers, including landowners' concerns about liability, risk aversion among fire management agencies, narrow burn windows, air quality limitations and other regulatory challenges. Now, public demand for prescribed fires is growing.

“I believe what moved the needle was, for several years in a row, there were high-severity fires in the news,” York said. “Wildfires were in the public zeitgeist. People began asking, ‘Why aren't we doing more prescribed fire?'”

Climate change is also intensifying the interest among the public and silviculture professionals. Because California is getting warmer and fire seasons are growing longer, high-severity fires are expected to increase.

“There would logically be a tipping point. Even though we reduce the growth of trees when we use fire, if it can prevent the loss of the forest entirely, it would be meeting the timber objective,” York said.

The vast tree die-off during the 2011-2016 drought was another jarring sign that the Sierra Nevada ecosystem is out of balance.

The U.S. Forest Service, which manages 20 million acres of forest in California, is using prescribed fire to reduce fire risk on federal forestlands, but scientists say it's not nearly enough to reduce the threat of catastrophic wildfire. CAL FIRE is ramping up its controlled burn efforts, but it will take time to address far-reaching areas of overgrown forestlands. The agency sometimes uses mechanical measures such as mastication and chaining before burning to pre-treat fuels and prepare units for burning.

“We need to work around communities first, and then move out to the wider landscape,” said CAL FIRE division chief Jim McDougald. “If a prescribed fire moves into a subdivision and burns houses, we take 100 steps back.”

UC Cooperative Extension forestry and natural resources advisor Susie Kocher. (Photo: @UCsierraforest)
UC Cooperative Extension is working with private landowners to encourage more prescribed burning to reduce fire risk, protect communities and timber. UCCE forestry and natural resources advisor Susie Kocher coordinated training sessions this year in four mountain communities. The sessions included local fire history and current fire research, prescribed fire permitting and legal considerations, fire weather forecasting and online tools, air quality and smoke management, fire terms and fire behavior, burn plan development, burn unit preparation and fire tools and equipment.

“Burning is a key element of forestland management and it can be safe if done properly,” Kocher said. “We provide classroom instruction and invite participants to join a live prescribed fire at Blodgett Forest as part of their training so they become familiar with the process.”

At the training sessions, UC Cooperative Extension advisor Lenya Quinn-Davidson said that in some cases, private landowners can conduct burns themselves. In her hometown in Trinity County, many ranchers and landowners conduct small broadcast burns to reduce fuels and improve forage. These burns are typically quite small and usually conducted in the winter.

“This can be a good option for landowners who wish to burn small areas, but we need other options for bigger, more complex burns” Quinn-Davidson said.

In other parts of the country, landowners have formed Prescribed Burn Associations (PBAs) that allow landowners to work with neighbors and other community members on controlled burns, sharing equipment and labor while developing skills. The PBA model provides a low-cost, grassroots option for prescribed burning, and empowers landowners to work together, and with other key experts and partners, to bring fire back to the landscape, says Quinn-Davidson.

“People are desperate to do something about fire, and the PBA model gives them an option to actively engage with each other and with fire as a tool—it's very empowering,” said Quinn-Davidson.

UC Cooperative Extension area fire advisor Lenya Quinn-Davidson.

 

Posted on Monday, July 29, 2019 at 9:07 AM
Focus Area Tags: Environment

Can rakes save forests? Yes, as long as you have a drip torch in the other hand

A drip torch and a McCleod, two tools that can be used together to reduce the fuels on the forest floor. (Photo: Lenya Quinn-Davidson)

The humble rake has been in the spotlight in recent weeks, and its role as a forest management tool ridiculed and scorned. However, most fire professionals believe rakes are a necessary part of saving California's forests.

Those who are familiar with fire are undoubtedly familiar with the McLeod, which is a standard firefighting tool and … it is essentially a rake (one side is a rake with coarse tines and the other side has a flat sharpened hoe). The McLeod was created in 1905 by a U.S. Forest Service ranger who wanted a single tool that could rake fire lines (with the teeth) and cut branches and roots (with the sharpened hoe edge). The McCleod is used to scrape fuels off of a fire line, preventing fire spread. The use of hand tools like the McLeod continues to be one of the standard ways that wildfires are stopped (although often aided by the rake's bigger and more powerful cousin: the bulldozer).

While the McLeod is a fire-fighting tool, it is also an essential fire-managing tool. When conducting controlled burns (i.e., purposeful fire), the fire is contained within desired areas by diligent raking with McLeods and other hand tools. These tools are necessary for conducting controlled burns.

While it isn't feasible to reduce fire risk by raking the forest with hand tools, if you hold a drip torch in the other hand, you could get the work done.

A drip torch consists of a canister for holding fuel that comes out of a spout (with a loop to prevent fire from entering the fuel canister) and a wick from which flaming fuel is dropped to the ground when the wick is ignited. The drip torch is the most common tool for lighting prescribed burns, which can be used to remove excess fuel buildup in the forest.

In a forest setting, these two tools — the rake and the torch — must be used together. Without a rake, the fire is not easily contained. And without a drip torch, the fuel that was raked cannot burn. Of course, prescribed burns rely on a number of other pre-specified factors (the prescription), including wind, temperature and humidity.

Using fire in a controlled manner drastically reduces the impacts of wildfire in a forest. Typically flames are kept low and most or all of the trees survive the fire, while much of the dead material on the forest floor (the “fuel”) is consumed. This reduces the risk of the forest burning at high severity in the future, thereby protecting nearby homes and towns. It also reintroduces fire as an important ecosystem process, which improves the health and biodiversity of forests and maintains the ecosystem services they provide, including wildlife habitat, water filtration and carbon sequestration.

Participants at a University of California Cooperative Extension with their hand tools (including shovels, Pulaskis, and McCleods) are getting ready to cut fire line so that a prescribed fire will not escape containment. (Photo: Ames Gilbert)

Use of a rake and a drip torch together could make a great difference for reducing the impacts of wildfire in California and the West. The National Interagency Fire Center reported that during 2017, only half a million acres were treated with prescribed fire in the West, while 7.4 million acres (almost 15 times more) burned in wildfires. In the Southeastern U.S., where there is a long-standing tradition of prescribed burning, only 2 million acres burned in wildfires while over 5.5 million were burned using prescribed fire.

This was not always the case. Use of prescribed fire, or ‘light burning,' was once common in California until it was outlawed by federal and state policy in 1924. Although the merits of expanding its use are widely known and appreciated, it has been very difficult to do because of concerns about air quality, liability and lack of skilled burners. One of the biggest constraints is that we have very few people who have experience with ‘good fire' and very few qualified people who know how to safely burn.

Landowners at a UCCE prescribed fire training are 'holding' the fire on the left side of the fire line that was cut using rakes and other hand tools. The landowner on the far left is firing the burn unit with a drip torch. (Photo: Ames Gilbert)

As foresters and educators for the University of California Cooperative Extension, we are working to expand the use of prescribed fire on private forest and grasslands in California. Central to our efforts are educational events that give people an opportunity to experience prescribed fire first-hand. In the last two years, we have hosted workshops throughout northern California, and many of our workshops have included a live-fire component where landowners and other community members can try their hand at prescribed burning, under the direction and guidance of more experienced burners.

Our efforts in California are inspired by approaches in other parts of the country, including “Learn and Burn” events in the Southeast, prescribed burn associations in the Great Plains, and prescribed fire training exchanges (TREXs), an innovative training model developed by The Nature Conservancy's Fire Learning Network. All of these efforts have a focus on reconnecting people with fire, and they give participants the skills and experience needed to put fire back in the management toolbox.

A prescribed fire burns up to the fire line (installed with rakes and other tools) and stops. The fire is consuming fuel on the forest floor and leaving behind a a healthier and more fire safe forest. (Photo: Lenya Quinn-Davidson)

We hope that by empowering people to pick up the drip torch (and the rake) on their own properties, we can help them reduce the risk of wildfire and improve the health of their forest and range lands. There is no time to waste.

Posted on Tuesday, December 11, 2018 at 9:31 AM
Focus Area Tags: Natural Resources

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