Reposted from Berkeley News

For nearly half a century, lightning-sparked blazes in Yosemite's Illilouette Creek Basin have rippled across the landscape — closely monitored, but largely unchecked. Their flames might explode into plumes of heat that burn whole hillsides at once, or sit smoldering in the underbrush for months.

The result is approximately 60 square miles of forest that look remarkably different from other parts of the Sierra Nevada: Instead of dense, wall-to-wall tree cover — the outcome of more than a century of fire suppression — the landscape is broken up by patches of grassland, shrubland and wet meadows filled with wildflowers more abundant than in other parts of the forest. These gaps in the canopy are often punctuated by the blackened husks of burned trunks or the fresh green of young pines.

“It really is a glimpse into what the Sierra Nevada was like 200 years ago,” said Scott Stephens, a professor of environmental science, policy and management at the University of California, Berkeley, and co-director of Berkeley Forests.

Wildfire may be destructive, but it is also necessary for healthy forest regeneration, Stephens said. (UC Berkeley photo by Scott Stephens)

Stephens is the senior author of a new study that gathers together decades of research documenting how the return of wildfire has shaped the ecology of Yosemite National Park's Illilouette Creek Basin and Sequoia and Kings Canyon National Parks' Sugarloaf Creek Basin since the parks adopted policies for the basins — at Illilouette Creek in 1972 and Sugarloaf Creek in 1968 — to allow lightning-ignited fires to burn.

While the prospect of smoke over iconic Half Dome has worried politicians and tourists alike, the work of Stephens and his colleagues demonstrates that allowing frequent fires to burn in these basins has brought undeniable ecological benefits, including boosting plant and pollinator biodiversity, limiting the severity of wildfires and increasing the amount of water available during periods of drought. All these benefits are also likely to make the forest more resilient to the warmer, drier conditions brought by climate change, the research suggests.

“In many ways, fire has successfully been restored to Illilouette, and it has made for a complex mosaic of vegetation with cascading effects on things like water,” said study co-author Brandon Collins, who holds a joint appointment as a research scientist with Berkeley Forests and with the U.S. Forest Service. “In Illilouette, you can have patches of young, regenerating trees from a fire 15 years ago, or areas where a classic understory burn has resulted in big, old, widely-spaced trees. You can even have areas where fire has missed because there's more moisture, such as adjacent to a creek or on the edge of a meadow. All this complexity can happen in a really short amount of space.”

The study findings arrive in the middle of a critical fire season, when drought conditions throughout the western U.S. have already sparked numerous large wildfires, including the Dixie Fire, which, as of Aug. 8, was the second largest wildfire in California history. While climate change has played a role in increasing the severity of these fires, Stephens said, Illilouette Creek Basin serves as an example of how current forest conditions in the Sierra — largely shaped by decades of fire suppression — are also driving these massive blazes.

“I think climate change is no more than 20 to 25% responsible for our current fire problems in the state, and most of it is due to the way our forests are,” Stephens said. “Illilouette Basin is one of the few places in the state that actually provides that information, because there is no evidence of changes in fire size or in the severity of fires that burn in the area. So, even though the ecosystem is being impacted by climate change, its feedbacks are so profound that it's not changing the fire regime at all.”

Returning fire to Yosemite

For millennia, wildfires sparked by lightning, or lit by Native American tribes, regularly shaped the landscape of the western U.S., not only causing destruction, but also triggering necessary cycles of rebirth and regeneration. However, the arrival of European colonists in the late 1800s, followed by formation of the U.S. Forest Service in 1905, ushered in an era in which fire was viewed as the enemy of humans and forests alike, and the vast majority of wildfires were quickly extinguished.

By the 1940s and 1950s, a number of forest managers and ecologists had begun to question the wisdom of fire suppression, noting that the practice was eliminating valuable wildlife habitat and increasing the severity of fires by allowing decades of fuel buildup. These fire proponents included A. Starker Leopold, an acclaimed conservationist and professor of zoology and forestry at UC Berkeley, as well as Harold Biswell, a professor at UC Berkeley's School of Forestry.

In response to a foundational 1963 report led by Leopold, the U.S. National Park Service changed its policy in 1968 to allow lightning fires to burn within special fire management zones — usually remote regions at high elevations — where danger to human settlements was low. Sequoia and Kings Canyon National Parks established the first fire management zone in 1968, followed by Yosemite National Park in 1972.

“I think it was finally recognized that fire is an integral piece of these ecosystems, and there were a few key people who were willing to take the risk of letting these fires happen,” Collins said.

‘It isn't always clean, and it's not always nice'

Between 1973 and 2016, Illilouette Creek Basin experienced 21 fires larger than 40 hectares — approximately equal to 75 football fields — while Sugarloaf experienced 10 fires of that size. In Illilouette, the result today is a forest that may look a bit messy to the untrained eye, but it holds a lot of resilience.

“When some people visit Illilouette, they say, ‘Look at all these dead trees!'” Stephens said. “I think we have this idea that forests need to be green all the time and made up with only big trees. But it turns out that no forest can do that. It has to be able to grow young trees and regenerate. Illilouette is doing that, but it isn't always clean, and it's not always nice.”

In Illilouette, wildfire has created a more diverse array of habitats for animals like bees and bats, while allowing a variety of plant life to flourish. The detailed history of wildfires in Illilouette has also provided foresters with valuable information on how the impact of one wildfire on landscape and vegetation can influence the trajectory of the next wildfire.

“Since fires are generally allowed to burn freely in Illilouette, we could look at what happens when two fires have burned close to each other: When does the second fire burn into the area that was burned by the first fire, and when does it stop at the previous perimeter?” Collins said. “We found that it really depended on the amount of time that had passed since the first fire. If it had been nine years or under, fires almost never burned into a previous fire perimeter.”

Collins said that Illilouette has also given forest managers a unique opportunity to study how wildfire behaves under a variety of conditions, rather than only at its most dire.

“One of the things that's kind of perverse about the fire suppression policy is that we actually constrain fires to only burn under the worst conditions. If the fire is mellow, that's a good time to put it out, and, as a result, they only burn when we can't put them out,” Collins said. “But by letting these fires burn (in Illilouette), they're able to experience the full range of weather conditions. On bad days, some of these fires have really put up a pretty good plume. But on the flip side, they also get to burn under more moderate conditions, too, and it makes for really varied effects.”

Returning fire to Illilouette has also had the somewhat counterintuitive impact of increasing the availability of water in the basin, a key finding as California weathers yet another year of extreme drought.

Study co-author Gabrielle Boisramé, an assistant research professor at the Desert Research Institute in Nevada, began studying water in Illilouette as a Ph.D. student in environmental engineering at UC Berkeley. Her simulations and measurements indicate that small gaps in the tree canopy created by wildfires have allowed more water from snow and rainfall to reach the ground, while also reducing the number of trees competing for water resources. As a result, soil moisture in some locations in Illilouette increased as much as 30% between 1969 and 2012, which likely contributed to very low tree mortality in the basin during the drought years of 2014 and 2015.

Measurements also indicate that streamflow out of Illilouette Creek Basin has increased slightly since the managed wildfire program began, while streamflow out of other similar watersheds in the Sierras have all decreased. Boosting the amount of water that flows downstream is likely to benefit both the humans and the aquatic ecosystems that depend on this precious resource.

“There's more and more work being done that examines the effects of fire on hydrology, but most of the other research is looking at the effects of catastrophic fires that burned up an entire forest,” Boisramé said. “As far as we know, we're the only ones in the western U.S. studying a restored fire regime, where we're not just looking at one individual fire, but a number of fires of mixed severity that have occurred over natural intervals of time. There just aren't that many places to study the long-term effects of these repeated wildfires because Sugarloaf and Illilouette were the first areas in California — really the first western mountain watersheds — where they started allowing fires to burn most of the time.”

Fighting for fire

Most U.S. national parks now practice some form of fire use, rather than full fire suppression, and in 1974, the National Forest Service also changed its policy to also allow some fires to burn on its lands, although areas of fire use are rare in this agency. However, these federal fire use policies have struggled to gain a foothold, largely because of the inherent risks involved in managing wildfire.

Even in Sugarloaf Creek Basin, where many fires have been allowed to burn, there has also been significantly more fire suppression than in Illilouette, the study found. As a result, the ecological benefits in Sugarloaf are not as pronounced as those in Illilouette.

“I think one of the key things to recognize is that the landscape in Illilouette was already somewhat unique, partly because it is at slightly higher elevation than a lot of the forests we manage,” Collins said. “As a result, it already had a mix of vegetation with patches of meadows and rock, and I think maybe that gave managers a little more ease in letting fire happen there. It doesn't have the potential to really push off a giant megafire because it lacks the continuity that some of these other areas have.”

The lightning-sparked Empire Fire burned in Illilouette Creek Basin for nearly four months during the late summer and fall of 2017. (UC Berkeley photo by Scott Stephens)

While both naturally-sparked fires and prescribed burns could help large swathes of the Sierra forest become more resilient to both drought and high severity fire, opposition to national “let it burn” policies in California remains strong, with state and local fire agencies often favoring the safety of fire suppression.

Collins and Stephens both acknowledge that the current fuel density in much of the Sierra, mixed with the hotter, drier conditions already triggered by climate change, has made managing wildfire even riskier than it was when forest managers started allowing fires to burn in Yosemite in 1972. However, they argue, fire suppression will never succeed in the long term, because the longer that forest fuel sources are allowed to build up, the more likely it becomes that wildfires will turn catastrophic when they are finally sparked.

“In order to actually allow this to happen, political and public institutions need to be willing to accommodate risk, because there will be some unpredictability. There are going to be fires that get larger, and more severe burning in places that have had very little fire for a century or more,” Stephens said. “We can't guarantee that Illilouette is going to be the new outcome, because it started when climate change was not nearly as severe. So, political institutions will have to accommodate that, or the first fire that doesn't do exactly what we hope will shut down the whole program.”

Collins and Stephens also advocate for more aggressive prescribed burning and restoration thinning throughout the Sierra to help get the forests to a place where lightning-sparked fires can be allowed to burn more safely.

Stephens credits strong, early leadership at Yosemite — including that of study co-author Jan W. van Wagtendok, who received a Ph.D. from UC Berkeley in 1972 and went on to serve as a research scientist at Yosemite for most of his career — for taking the huge risk of launching the program and allowing early fires to burn in the park.

“It's been 50 years now, but I think what we've learned helps us understand what is possible,” Stephens said. “We have 10 to 20 years to actually change the trajectory of the forest ecosystems in our state, and if we don't change them in 10 or 20 years, the forest ecosystems are going to change right in front of our eyes, and we're just going to be passengers. That's why it's so important to continue this work.”

Previous funding from the U.S. Joint Fire Science Program, UC ANR Competitive Grants Program, and the National Science Foundation's Critical Zone Collaborate Network (award number 2011346) supported the research in this paper.

Study co-authors also include Sally Thompson of the University of Western Australia; Lauren C. Ponisio of the University of Oregon, Eugene; Ekaterina Rakhmatulina, Jens Stevens and Zachary L. Steel of UC Berkeley; and Kate Wilkin of San Jose State University.

Reposted from the UCANR News

“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!”

Towering coastal redwoods frame a Northern California highway. (Photo: Wikimedia Commons)

 

Reposted from the UC Berkeley College of Natural Resources News

 

Fire has been a central component in California's natural and human history for millennia. Native Americans' use of cultural burns in landscape management, in addition to lightning-ignited fires that burned unhindered, have long impacted most of the state's ecosystems. However in the late 1800s, California's landscape underwent an era of Euro-American fire exclusion and suppression. As the United States began suppressing fire across western ecosystems, forests became increasingly dense with fuel which easily ignites in warm weather conditions.

In a study published in Frontiers in Ecology and the Environment  today, environmental science, policy, and management professor Scott Stephens and co-authors investigate the role which fire and restoration thinning could play in restoring California's forests. Stephens argues that allowing forests to burn does not necessarily conflict with the government's environmental objectives to promote carbon storage and water availability. In the long-term, fire and restoration thinning can help forests continue to provide natural services while building ecosystem resilience to climate change. 

A century of fire suppression coincided with the loss of larger, more fire-resistant trees from selective logging. With the worsening impacts of climate change, wildfires have grown increasingly destructive and high-intensity in recent years, and megafires threaten the biodiversity of many native ecosystems. 

Stephens argues for the return of fire in California's forest management techniques. “With climate change and continued ignitions from people and lightning, there is a great need to move decisively,” says Stephens. “The good news is rather than conflicting with other environmental objectives, fire and restoration thinning employed now will provide numerous co-benefits.” 

The authors focus on two primary management strategies: burning and restoration thinning. Fire treatments include prescribed fires, in which managers intentionally burn an area in accordance with a site-specific plan. Prescribed burns reduce dead wood, leaf litter, and small trees, which act as hazardous fuel layers in seasonally dry forests. Additionally, forest managers can monitor wildfires that are ignited naturally by lightning and, where appropriate, allow such ignitions to burn—a technique that has improved the ecological resilience of several National Parks and forests in much of the United States. 

 

Restoration thinning—activities such as chipping, shredding, and whole-tree removal—can reduce fuel and mimic the effects of burning. However, mechanical thinning practices do not aid the many native species which rely on smoke and heat to germinate or on burnt habitat to thrive.

Importantly, the study describes how such management strategies can improve overall biodiversity, water quantity, and carbon sinks. Pyrodiversity, or the degree of heterogeneity in the age and size of a burned landscape, can support more diverse bird, pollinator, and flowering plant communities. The authors describe the challenge in maintaining complex tree canopy structures for threatened species, such as the California spotted owl. In addition to increasing streamflow and enhancing long-term carbon sequestration, the proposed management strategies could lower the likelihood of high-severity fires in the future. 

“Even though increasing the scale of restoration is daunting, I am optimistic,” says Stephens. “Forests are just too important to the people and wildlife of California. But we need to act or severe wildfires and drought will continue to change forests right in front of us. We can and need to do better.”

Management strategies would need to account for the difficulty in controlling hazards from smoke, as well as how volatile weather conditions can cause undesired fire outcomes. To ensure the safety of the forest and nearby communities, the study finds that prescribed burn plans must integrate information on weather, topography, fuel type, ignition patterns, and other factors. The authors call for increased collaboration between Native American tribes and forest managers, highlighting the importance of longstanding indigenous knowledge and practices. 

Now the COVID-19 pandemic is expected to impact fire suppression, an activity that necessarily involves groups working in close proximity. “Firefighters train, sleep, shower, eat, and fight fire in groups, and the effectiveness of firefighters depends on the ability to deploy and work closely to extinguish fires,” says Stephens. “New protocols are being developed for this summer and fall that will work to make groups smaller and to increase fire prevention. While these measures are needed this year, they do not address the fundamental fire problems in California forests that are addressed in this paper.”

The study was conducted in collaboration with researchers from the University of California, Merced, the University of New Mexico, the University of Wisconsin, Madison, Colorado State University, and the University of Western Australia. Read the full paper in Frontiers in Ecology and the Environment  website. 

Reposted from the UC Berkeley News

Fire crews work on a wildfire in California. The 2019 fire season could be as destructive as earlier fire seasons. (U.S. Forest Service photo by Mike McMillan under Creative Commons 2.0)

Eight months after the Camp Fire consumed the Northern California town of Paradise and was pronounced the deadliest wildfire in state history, California is facing the potential in the coming months for more death and destruction.

Scott Stephens, a UC Berkeley professor of fire science, says the heavy rains of February and March have left California grasslands with perhaps twice as much burnable fuel as this time a year ago.

“Most of the time, you'd have one ton of dry mass per acre, and right now it's about double that,” Stephens, who has spent a quarter century in Berkeley working on fire behavior, fire ecology and forest policy, says. “I would expect grassland fires to be more intense and move around more quickly because of that.

“All that dry grassland will be responsive to sparks and flying burning embers. The fuel load will increase flame lengths. Once the grasslands start to burn, they could produce more embers themselves, since they have higher fuel loads.”

Stephens says California could help itself greatly by following the Australian model of fire prevention, where there is regular governmental outreach to people who live in fire-prone areas.

That's one reason he's a keen booster for Senate Bill 462, which is currently under consideration in Sacramento. One segment of the bill calls for the development of a group of outreach advisors who could be in the field long before a firestorm, giving advice about fire issues to those most likely to need it.

Data from the weather satellite GOES shows the Camp Fire as it spread from ignition and through the town of Paradise on Nov. 8, 2018. Such images, downloaded quickly, could be used to alert fire, police and residents of developing wildland fires. (Image courtesy of Jeff Chambers)

“This is not an average year,” he says. “The grasslands in some places are twice as tall as normal. That makes fire prevention more challenging, particularly at the urban wildland interface,” where homes are built on or adjacent to fire-prone lands.

“In general,” he adds, “the state has not done well to engage people and acquaint them with their vulnerabilities.”

“The UC Extension programs across the state have been doing this kind of thing in agriculture for 50 years,” Stephens says. “These are people who live in the counties most impacted and who can make a difference. We should be taking some inspiration from Australia and do the outreach about fire within communities and city councils.”

The Camp Fire at 10:45 a.m. on Thursday, Nov. 8, 2018, four hours after it broke out, likely at the easternmost edge of the burn (right). (Landsat data analysis and overlay courtesy of Jeff Chambers)

Stephens has spoken several times in Sacramento on behalf of SB 462, calling it “a critical program for the state to move forward.” The Camp Fire, and the Carr and the Tubbs fires that preceded it, may have gotten California out of a legislative quagmire concerning fire, although it's an open question whether or not the legislature will ever get a bill to Gov. Gavin Newsom's desk.

“In my two years doing this, I've never seen the state do what has been done the last two years,” Stephens says. “Both the legislature and the governor are moving into fire areas, trying to understand things better. This bill came out of the education committee in the Senate and got the support of a lot of environmental committees.”

As originally written, the bill's funding would have been $20 million. Once the bill arrived in the appropriations committee, however, that figure was reduced to $1 million, and the bill currently is awaiting consideration by the Assembly Natural Resources Committee.

Last November's Camp Fire left almost nothing behind in the Northern California town of Paradise. (Photo by Ashley Estep-Earley under Creative Commons)

Stephens says the funding cut would mean only two or three people could be hired to do the kind of outreach he envisions across the state. The original funding would have seen the hiring of perhaps 15.

Wildfire season in California has typically run from mid-summer through late autumn, although the last two seasons have stretched that. Stephens says getting ahead of the wildfire season would include, in addition to outreach, the passage of Senate Bill 462 and a concerted effort to mow or trim the dried grasslands.

“We need to see what is happening,” Stephens says. “Right now, the people who are dying in these fires are the elderly, the vast majority of whom are over 65. These are people who are not as mobile and who don't have the same resources. They are the ones who need this outreach.”