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Forest Research and Outreach Blog

Dry conditions keep sudden oak death in check, yet significant outbreaks continue

Google map shows results of the SOD blitzes available online at sodblitz.organd Green icons identify trees sampled that tested negative for SOD. Red icons were SOD-infected trees.
Sudden oak death, which has killed millions of trees in California over the past 20 years, is spreading more slowly, according to California's most recent citizen-science sudden oak death survey. The 2018 SOD Blitz results indicate Phytophthora ramorum (the pathogen known to cause SOD) infection is currently less prevalent in many wildland urban interface areas, though significant outbreaks are still occurring in some locations.

Overall, 3.5 percent of the trees (based on those areas sampled during the blitzes) were found to be P. ramorum positive, a threefold drop from 2017. Yet, in San Mateo, Santa Clara and Santa Cruz counties, infection levels were estimated to be as high as 19 percent, followed by 12.7 percent in the East Bay.

"SOD blitzes detected the highest levelsoffoliar infections by OD in 2017,” said SOD BlitzfounderMatteoGarbelotto, UC Berkeley forest pathology and mycology Cooperative Extension specialist and adjunct professor. “As predicted, those high levelsoffoliar infections were responsible for a high increase of infection of oaksandtanoaks by SOD.

"Oaks and tanoaks were infected last year and will be showing symptoms such as bleeding in the stem and canopy drying this year and in the next two years to follow. Hence, despite a reduction of SOD infection on leaves of California bay laurels and leaves of tanoaks in 2018, we can expect a sharp increase in oak and tanoak mortality in 2018, 2019 and 2020."

Notable outbreaks were detected in Alameda (El Cerrito and Oakland urban parks, San Leandro, Orinda, Moraga), Marin (Novato, Day Island, Woodacre, Sleepy Hollow, McNears Beach, China Camp State Park, north San Rafael, Tiburon Peninsula, east and west peak of Mt. Tamalpais, Marin City), Mendocino (south of Yorkville), Monterey (Carmel Valley Village, Salmon Creek Trail in southern Big Sur), Napa (east Napa city), San Mateo (Burlingame Hills, west of Emerald Hills and south of Edgewood Rd, Woodside ), Santa Clara (Los Altos Hills, Saratoga, Los Gatos, along Santa Cruz Co border), Santa Cruz (along the Santa Clara Co border, Boulder Creek), and Sonoma (near Cloverdale, east and west of Healdsburg, west of Windsor, east of Santa Rosa, west of Petaluma) counties.

Several popular destinations where P. ramorum was found positive during the 2017 Blitz were negative for the pathogen in 2018, including Golden Gate Park and the Presidio of San Francisco, the UC Berkeley campus, and Mount Diablo State Park. Samples from San Luis Obispo and Siskiyou counties were also pathogen-free as were those from the southern portion of Alameda County.

"We encourage everyone in affected counties to look at the Blitz results online and to attend one of the fall workshops to learn how to protect their oaks from SOD,” Matteo Garbelotto.

“It is encouraging that SOD has yet to be found in the forests of California's northern-most counties, San Luis Obispo County and southern Alameda County,” said Garbelotto.

“It is also encouraging to see that despite its continued presence in the state for more than 20 years, SOD infection rates drop during drier years,” he said. “However, in 2018, we identified a number of communities across several counties where significant outbreaks were detected for the first time, and the Salmon Creek find in Monterey County is the southernmost positive WUI (wildland-urban interface) tree detection ever. Until the 2018 Blitz, only stream water had been found positive in the Salmon Creek area. We encourage everyone in affected counties to look at the Blitz results online and to attend one of the fall workshops to learn how to protect their oaks from SOD.”

Citizen-science SOD Blitz workshops

SOD Blitz Workshops are being held this fall in Santa Rosa (Oct. 10), Portola Valley (Oct. 16) and Berkeley (Oct. 17). The trainings will discuss Blitz results and recommendations for protecting oaks in the WUI. Workshops are intended for the general public, tree care professionals and land managers (see for details). Two International Society of Arboriculture continuing education units will be offered at each training. Data collected from the Blitz (both positive and negative samples) have been uploaded to the SOD Blitz map ( ) as well as to SODmap ( and to the free SODmap mobile app, which can serve as an informative management tool for people in impacted communities.

SOD Blitz volunteers collect leaf samples and record the location using the SODmap mobile app.

Twenty-five SOD Blitz surveys were held in 2018 in the WUI of 14 coastal California counties from the Oregon border to San Luis Obispo County and included three tribal land surveys. The 304 volunteers surveyed approximately 13,500 trees and submitted leaf samples from over 2,000 symptomatic trees to the Garbelotto lab for pathogen testing.

SOD Blitzes are a citizen science program, which train participants each spring to identify symptomatic tanoak and California bay laurel trees in the WUI and to properly collect samples in the interest of generating an informative map of P. ramorum disease symptoms over time. Samples are tested for the presence of the pathogen at UC Berkeley and results are posted electronically each fall. Now in its eleventh year, the SOD Blitz program is one of the first in the world to join researchers and volunteers in a survey for a tree disease.

SOD Blitz surveys were made possible thanks to funding from the US Forest Service State and Private Forestry, Midpeninsula Regional Open Space District, and the PG&E Foundation. The Blitzes were organized by the UC Berkeley Garbelotto lab in collaboration with the National Park Service, Presidio Trust, San Francisco Public Utilities Commission, Midpeninsula Regional Open Space District, Save Mount Diablo, Land Trust of Santa Cruz County, East Bay Regional Park District, Santa Lucia Conservancy, Sonoma State University, UC Santa Cruz Arboretum, Los Padres National Forest, City and County of San Francisco Department of Recreation and Parks, UC Berkeley Botanical Garden, and California Native Plant Society.

Video of Dr. Matteo Garbelloto describing the three steps to managing sudden oak death.

For information on the status of P. ramorum/SOD tree mortality in California wildlands, see the US Forest Service 2018 Aerial Detection Survey results at

For more information on the SOD Blitzes, visit or contact Katie Harrell at (510) 847-5482 or For more information on Sudden Oak Death and P. ramorum, visit the California Oak Mortality Task Force website at or contact Harrell.

Posted on Tuesday, October 9, 2018 at 4:30 PM
  • Author: Katie Harrell

Clean Water Act dramatically cut pollution in U.S. waterways

Reposted from the UC Berkeley News

The 1972 Clean Water Act has driven significant improvements in U.S. water quality, according to the first comprehensive study of water pollution over the past several decades, by researchers at UC Berkeley and Iowa State University.

The team analyzed data from 50 million water quality measurements collected at 240,000 monitoring sites throughout the U.S. between 1962 and 2001. Most of 25 water pollution measures showed improvement, including an increase in dissolved oxygen concentrations and a decrease in fecal coliform bacteria. The share of rivers safe for fishing increased by 12 percent between 1972 and 2001.

A forest stream

The Clean Water Act has decreased measures of water pollution in U.S. lakes, streams and rivers.

Despite clear improvements in water quality, almost all of 20 recent economic analyses estimate that the costs of the Clean Water Act consistently outweigh the benefits, the team found in work also coauthored with researchers from Cornell University. These numbers are at odds with other environmental regulations like the Clean Air Act, which show much higher benefits compared to costs.

“Water pollution has declined dramatically, and the Clean Water Act contributed substantially to these declines,” said Joseph Shapiro, an associate professor of agricultural and resource economics in the College of Natural Resources at UC Berkeley. “So we were shocked to find that the measured benefit numbers were so low compared to the costs.”

The researchers propose that these studies may be discounting certain benefits, including improvements to public health or a reduction in industrial chemicals not included in current water quality testing.

The analyses appear in a pair of studies published in the Quarterly Journal of Economics and the Proceedings of the National Academy of Sciences.

Cleaning up our streams and rivers

Americans are worried about clean water. In Gallup polls, water pollution is consistently ranked as Americans' top environmental concern – higher than air pollution and climate change.

Since its inception, the Clean Water Act has imposed environmental regulations on individuals and industries that dump waste into waterways, and has led to $650 billion in expenditure due to grants the federal government provided municipalities to build sewage treatment plants or improve upon existing facilities.

However, comprehensive analyses of water quality have been hindered by the sheer diversity of data sources, with many measurements coming from local agencies rather than national organizations.

To perform their analysis, Shapiro and David Keiser, an assistant professor of economics at Iowa State University, had to compile data from three national water quality data repositories. They also tracked down the date and location of each municipal grant, an undertaking that required three Freedom of Information Act requests.

“Air pollution and greenhouse gas measurements are typically automated and standard, while water pollution is more often a person going out in a boat and dipping something in the water.” Shapiro said. “It was an incredibly data and time-intensive project to get all of these water pollution measures together and then analyze them in a way that was comparable over time and space.”

In addition to the overall decrease in water pollution, the team found that water quality downstream of sewage treatment plants improved significantly after municipalities received grants to improve wastewater treatment. They also calculated that it costs approximately $1.5 million to make one mile of river fishable for one year.

Comparing costs and benefits

Adding up all the costs and benefits — both monetary and non-monetary — of a policy is one way to value its effectiveness. The costs of an environmental policy like the Clean Water Act can include direct expenditures, such as the $650 billion in spending due to grants to municipalities, and indirect investments, such as the costs to companies to improve wastewater treatment. Benefits can include increases in waterfront housing prices or decreases in the travel to find a good fishing or swimming spot.

The researchers conducted their own cost-benefit analysis of the Clean Water Act municipal grants, and combined it with 19 other recent analyses carried out by hydrologists and the EPA. They found that, on average, the measured economic benefits of the legislation were less than half of the total costs. However, these numbers might not paint the whole picture, Shapiro said.

“Many of these studies count little or no benefit of cleaning up rivers, lakes, and streams for human health because they assume that if we drink the water, it goes through a separate purification process, and no matter how dirty the water in the river is, it's not going to affect people's health,” Shapiro said.  “The recent controversy in Flint, MI, recently seems contrary to that view.”

“Similarly, drinking water treatment plants test for a few hundred different chemicals and U.S. industry produces closer to 70,000, and so it is possible there are chemicals that existing studies don't measure that have important consequences for well-being,” Shapiro said.

Even if the costs outweigh the benefits, Shapiro stresses that Americans should not have to compromise their passion for clean water — or give up on the Clean Water Act.

“There are many ways to improve water quality, and it is quite plausible that some of them are excellent investments, and some of them are not great investments,” Shapiro said. “So it is plausible both that it is important and valuable to improve water quality, and that some investments that the U.S. has made in recent years don't pass a benefit-cost test.”

Catherine L. Kling, professor of agricultural and life sciences and environmental economics and Cornell University, is a co-author on the Proceedings of the National Academy of Sciences paper.

Research funding was provided by the U.S. Department of Agriculture through the National Institute of Food and Agriculture Hatch Project IOW03909 and Award 2014-51130- 22494 and a National Science Foundation Award SES-1530494. Much of the research was completed while Shapiro was at Yale University.

Posted on Tuesday, October 9, 2018 at 12:03 PM
  • Author: Kara Manke

High-Risk Housing Developments Fan the Flames for Wildfire

Reposted from California Magazine


The world certainly seems more flammable these days. Thousands of homes were lost last year in Sonoma County alone, and wildfires have raged across California all summer. And not just in California: Records from the federal National Interagency Fire Center show that U.S. acreage burned in wildfires leaped from 1.8 million in 1995 to 10 million in 2017.

But even as the burned acreage has jumped exponentially, the number of fires—or “ignitions” in wildfire-speak—dropped significantly, from 82,234 in 1995 to 71,499 in 2017. Why the discrepancy? Put simply, fires are getting harder to control, so they're getting bigger. To blame are the build-up of forest fuels from decades of aggressive fire suppression as well as drier, hotter, and windier conditions caused in large part by climate change.

That's only part of the problem, though. The fires are getting costlier, both in terms of human life and property loss. And a major—perhaps the major—driver to this trend is the “expanding bull's eye” of high-risk development, specifically the rapid growth of Wildland-Urban Interface (WUI).

Conceptual model of the “expanding bull's-eye effect” with increasing development spreading from an urban core over time. // Ashley et al. 2014

“Interface” is that transitional zone between suburbs or cities and forested areas. From a firefighter's perspective, WUI combines the worst of both realms: Interface areas are not only cheek-to-jowl with fuel-rich forests, they're also often characterized by dense housing tracts landscaped with lush, highly flammable vegetation. Today's wildfires, in short, are not your grandpa's wildfires; they're usually hybrid, human-started fires, involving both structures and forests, which greatly complicates the task for wildfire fighters and escalates the cost in life and property.

A recent study shows that WUI, primarily from suburban and recreational development, is the fastest-growing land-use category in the lower 48 states. And home losses from wildfire correspond directly to the expansion of interface.

Anu Kramer, a postdoctoral research associate at the University of Wisconsin who took her PhD in environmental science, policy and management at Cal, co-authored the paper in the Proceedings of the National Academy of Sciences that examined WUI changes from 1990 to 2010.

“We found that there was a 33 percent increase in WUI for the period and a 41 percent increase in new homes built in WUI areas—from 30.8 million to 43.4 million,” Kramer said—meaning there are more and more zones where development abuts wildland. “Basically, this translates as greatly increased fire risk.”

Kramer and her colleagues confirmed that post-fire construction tends to concentrate in areas of equal or higher fire risk than those that had last burned.

Those statistics suggest that neither policy makers nor home owners have grasped the profound risks implied by building in pleasant, leafy—and highly combustible—environs, particularly in the West.

“The main takeaway from our most recent research is that these interface areas need to be targeted for outreach—education for home owners on creating defensible spaces, and regulations, and funding that would result in such things as fuel breaks, more sensible zoning, and mandates on fire resistant construction materials.”

Instead, there seems to be a kind of collective determination to repeat the mistakes of the past.

“I'm involved in some research on rebuilding trends after wildfires, looking at where new homes are going in,” said Kramer. “On average, 94 percent of buildings [in a burn zone] have been rebuilt after 25 years.”

Kramer and her colleagues created a computer model, which confirmed that post-fire construction tends to concentrate in areas of equal or higher fire risk than those that had last burned.

“Miranda Mockrin [a researcher with the U.S. Forest Service] has done a lot of work in Colorado on the social science aspects of wildfire,” Kramer said. “She looked at zoning changes after fires and found that yes, sometimes zoning gets stricter and people may be encouraged to build with materials that are more fire-safe, but in the majority of cases there were no changes, and in some instances restrictions were actually reduced. The potential for learning and adaptation after fires just isn't being fulfilled.”

Local governments are incentivized to rebuild as quickly as possible to recoup lost tax revenues and bring civic and economic life back to comfortable 

That dynamic seems in play in the North Bay, observed Kramer, where homes currently are being rebuilt in the exclusive Fountaingrove area. This enclave of expensive houses was located along a ridge on the margins of Santa Rosa. Just under a year ago on the evening of October 8 th , the Tubbs Fire roared through the neighborhoods, consuming most of the homes and killing several people. The steep slopes and canyons of the ridge acted as chimneys, concentrating the full fury of the wind-driven flames onto the ridge top development.

It was a horrific event, but it was hardly an outlier. In fact, it had been predicted. In 1964, the Hanley Fire tracked virtually the same route as the Tubbs Fire, including the area now occupied by Fountaingrove. But in 1964, Fountaingrove didn't exist, and the Hanley Fire destroyed relatively few structures. When construction on Fountaingrove started in the 1990s, many residents protested to Santa Rosa regulators, citing the Hanley blaze.

So why rebuild in high-risk areas? As Kramer explains, local governments are incentivized to rebuild as quickly as possible to recoup lost tax revenues and bring civic and economic life back to comfortable baselines. Unfortunately, environmental and geophysical changes—more frequent high wind events, longer and more frequent droughts, higher summertime temperatures and milder winters—mean that an increasing number of communities, even those outside of wildland interfaces, are considered high-risk for catastrophic wildfire.

The past few fire-ravaged years have made it clear that we have reached a tipping point. Epic wildfires seem certain to gain in frequency and destructive power in coming decades.

The Tubbs Fire, for example, didn't just burn Fountaingrove, a development with a significant WUI. It also flattened 1,200 homes in Coffey Park, an older middle-class development in a thoroughly suburban area located west of Highway 101 and far from anything that could be construed as a “wildland.” Extremely high winds drove masses of embers across 101, where they ignited structures and landscaping in Coffey Park and surrounding business complexes. Such winds were once considered anomalous by fire scientists. Not anymore. If ferocious wildfire-associated winds aren't the new normal, they're on their way. Winds reaching 143 mph destroyed scores of homes in the recent Carr Fire in Redding, during which a literal fire tornado killed two firefighters.

“[The Tubbs and Carr Fires] demonstrate how these strong winds can influence where a fire goes and what it does,” said Kramer. “They also show we need better models for predicting impacts and assessing risks. The models currently used by Cal Fire [California's state wildfire fighting agency] have a pretty basic wind component that doesn't account for the kind of high wind events we've begun seeing. So Max Mortiz [the head of the Mortiz Fire Regimes and Ecosystems Management Lab at Cal] is working with Cal Fire to bring their models up to date.”

The past few fire-ravaged years have made it clear that we have reached a tipping point. Epic wildfires are no longer rare, and they seem certain to gain in frequency and destructive power in coming decades. Moreover, the number of communities at dire risk is much higher than has been assumed. As Kramer's work reveals, wildfire losses seem proportional to the growth of WUI. We can't eliminate wildfire, but we can certainly reduce the impacts.

Paradoxically, that involves introducing more fire—controlled fire—into our wildlands to consume heavy fuel concentrations. It also entails moderating the dizzying expansion of WUI. Left unregulated, the trends in housing growth will simply perpetuate the destruction.

Posted on Thursday, September 6, 2018 at 11:04 AM
  • Author: Glen Martin

‘He brought us all together’: UC Berkeley professor, forestry economist Peter Berck dies at 68

Reposted from The Daily Californian


Peter Berck, one of the world's foremost forestry economists and a professor in UC Berkeley's Department of Agricultural and Resource Economics, or ARE, died of cancer Aug. 10 at age 68.

Berck earned a bachelor's degree in mathematics from UC Berkeley and a doctorate in economics from the Massachusetts Institute of Technology. He returned to campus as an assistant professor in 1976, where he remained for the duration of his career. Berck never retired, continuing to advise students and conduct research even as his illness worsened, according to his wife, Cyndi Berck.

“Peter was probably the most beloved professor in any field,” Cyndi Berck said. “He had an open door policy in his office — he always had tea and coffee and loved hearing his students' life stories.”

Cyndi Berck said her husband had a love of the outdoors that began after he joined the Boy Scouts of America while growing up in New York. He became involved in leadership positions with the Boy Scouts as a district chair and assistant scoutmaster of Berkeley Troop 6 when his youngest son joined the organization.

“He wanted to expand ethnic diversity in the sense that scouting is for everyone,” Cyndi Berck said. “He was supportive of progress in the last several years of opening the scouts up regardless of sexual orientation or gender and he was in a position to be part of that process.”

Peter Berck's love for the outdoors translated into his academic pursuits — he wrote more than 100 research papers on a variety of topics, including forestry economics, management of natural resources and agricultural adaptation to climate change, according to Cyndi Berck.

Peter Berck recently developed a computer model to simulate impacts of environmental regulation on the California economy, which is now widely used by the California government to inform the state's fiscal policy, according to the ARE website. Cyndi Berck said her husband used this model to analyze the impacts of California greenhouse gas regulation, which determined that moving toward renewable energy would reduce the price of energy in California.

Though a prominent researcher, Peter Berck was also well-known for his dedication to his students, according to ARE professor Jeffrey Perloff. Upon hearing of Peter Berck's illness, some of his former graduate students created a Facebook page dedicated to him that received more than 900 comments, according to Perloff. He added that “not many people can generate that kind of love.”

ARE professor Sofia Villas-Boas said some people on the Facebook page created the term “BERCKonomics” — the capitalized letters stand for bonding over environment, resources, coffee and kindness — to summarize Peter Berck's legacy. Villas-Boas said that although there were many qualities repeated in the comments to describe Peter Berck, the quality most often noted was that “he brought us all together.”

“We had a connecting open door between our offices and we became really good friends,” Villas-Boas said. “Later we realized that I was like his sister and he was my brother. It was really a blessing.”

Peter Berck is survived by his wife, three children — David, Michelle and Joseph — his brother, Alan, and four grandchildren.

Posted on Sunday, August 26, 2018 at 5:57 PM

UC system reaching an existential ‘tipping point,’ new paper concludes

Reposted from the UC Berkeley News

A photo of a lecture hall at UC Berkeley.

The 10-campus UC system is approaching a tipping point where it it may not be able to excel without increased state support. (UC Berkeley photos by Elena Zhukova)

After years of sagging funding and rising enrollment, the University of California system is nearing a “tipping point” where it cannot continue to grow with California's population and labor needs without seeking new revenues and state reinvestment, according to a new report from UC Berkeley's Center for Studies of Higher Education.

The report, published this week, provides the first detailed historical analysis of the 150-year-old, 10-campus UC system's funding model, which was once based on enrollment workload. A stable source of state funding provided the foundation for UC's growth in students, research, and public service programs.

“Look, California is the fifth-largest economy in the world and our pioneering public higher education system is a big reason for this,” said John Aubrey Douglass, one of the paper's authors and a senior research fellow at the center, which is affiliated with the Goldman School of Public Policy. “UC has been a terrific engine for socio-economic mobility.”

The 47-page paper provides a picture of a university that has navigated state funding cuts while enrolling increasing numbers of students, maintaining its research productivity and serving California's economy and social life.

Among the findings are the successes of UC system assets:

  • UC awards 33 percent of the state's bachelor degrees, and 85 percent of students graduate within six years, compared to the national average of 59 percent
  • The UC system produces 75 percent of California's life science Ph.D.s, 65 percent of the state's engineering and computer science Ph.D.s and roughly half of the state's medical students and residents
  • Forty-two percent of undergraduates are from households where neither parent has a college degree.
  • Just four of the 10 UC campuses enroll more low-income students than all the Ivy League universities combined. These students graduate at the same rates as their wealthier peers and earn more than their families soon after graduation.
  • UC researchers generate an average of five new inventions a day, and roughly 500 patents a year

And the changing financial picture:

  • While state support for the UC system shrank dramatically beginning in 1990, the UC system continued to expand enrollment in line with California's population growth, from 166,500 in 1990 to nearly 273,000 today
  • Tuition hikes have not fully replaced cuts in state funding, and 33 percent of all tuition increases are returned to students in the form of financial aid
  • California residents have not borne the brunt of tuition hikes. At UC Berkeley, nonresident undergraduates make up roughly 19 percent of the student body and pay almost 40 percent of the tuition the school collects
  • Roughly 57 percent of UC undergraduates from California pay no tuition
  • Compared to the size of California's economy, the government's per-student contribution to the UC system has fallen by 66 percent since 2000

And while the report also found that there is little statistical evidence to suggest the quality of a UC education has declined as state funding has shrunk, Douglass and his co-author Zachary Bleemer, who directs the UC ClioMetric History Project at the higher education study center, argued that that trend is unlikely to last.

“We may be at the end of California's once coherent effort, from 1910 to approximately 1990, to provide resources for UC to grow with California's population and help meet the state's labor and research needs and desire to mitigate inequalities in our society,” they wrote.

A photo of students on the UC Berkeley campus.

The report found that there is little statistical evidence to suggest the quality of a UC education has declined as state funding has shrunk, but that trend may not last.

Such a trend could leave UC leaders faced with difficult choices: limit enrollment and undermine the UC system's mission to serve Californians, or continue to expand enrollment as California's population grows and sacrifice educational quality, according to the paper.

Douglass and Bleemer go on to examine possible – and sometimes controversial – ways the UC system could adapt to an unpredictable future with limited state funding, including charging higher tuition for prestigious campuses like UC Berkeley or UCLA, cutting the amount of financial aid offered to students, charging higher tuition for lucrative degrees like computer science or offering online degree programs.

And while those changes may be necessary even with increased state support, Douglass and Bleemer conclude that the only sustainable solution is increased government support.

“The resources are there, and the total investment needed to allow UC, and CSU, to grow and maintain access to future Californians are relatively small compared to the state's GDP,” Douglass said. “California's knowledge-based business are already clamoring for more people from UC, and more people with Bachelor's and Ph.D.'s.”

Contact Will Kane at

Posted on Sunday, August 26, 2018 at 12:49 PM
  • Author: Will Kane

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