- Author: Jeannette E. Warnert
California oak woodlands are highly prized ecoregions where stately trees, many of them hundreds of years old, are cornerstones of a habitat for wildlife and native plants. Sadly, some of these ecosystems are seriously threatened by exotic pests and diseases, encroachment by less desirable vegetation, and wildfire.
Each year, UC Cooperative Extension hosts workshops to share scientific developments aimed at conserving these important habitats – and the economic value of ranching – on oak woodlands, which are found on the lower elevation slopes of the Sierra Nevada, the Coast Range and other foothill areas of California.
Typically, the workshops are held in person and draw moderate-sized audiences for presentations, questions and answers, and field trips. Because of the COVID-19 pandemic, this year's workshop was offered online in April with pre-recorded presentations available for viewing at the participants' convenience and a live question-and-answer session on Zoom.
The retooled event garnered 500 registrants, over 300 views of the YouTube videos and 140 participants in the live Q&A session. The presentations and Q&A session are still available online for future viewing as well.
“People from all walks of life participated, including those with professional and personal interest in oak woodlands,” said Yana Valachovic, UCCE forest advisor in Humboldt and Del Norte counties and a conference organizer.
Presentations at the 2020 conference included the following topics:
Encroachment by Douglas-fir
In Northern California, the biodiversity of oak woodlands is being threatened by Douglas-fir encroachment. The oaks' shade helps the young conifers get established with protection from harsh sun. In time, the fast-growing Douglas-fir trees pierce the oak canopies and begin to crowd out the areas' native understories, which are important for the diversity of birds, mammals and reptiles attracted to oaks.
As the Douglas-fir continue to grow and multiply, they threaten the very lives of the oak trees and the unique ecosystem they dominate.
To better understand the Douglas-fir encroachment, Valachovic established 10 research sites in Humboldt and Mendocino counties to gather information about the fate and the age of oaks. She and her research partners determined the ages of the oaks and firs, and counted the seedlings, saplings, snags and understory vegetation.
“With this research, we were able to demonstrate that even though the oak trees can be smaller in diameter they are much older than the Douglas-fir trees,” Valachovic said. “The encroachment process is happening quickly, and the oaks are falling out of the system.”
The shift appears to have been initiated in the mid-19th and early-20th centuries, coinciding with the Gold Rush and wildfire suppression.
With the data confirming Douglas-fir encroachment, Valachovic turned her attention to oak woodland restoration. At 14 sites in Humboldt and Trinity counties, her team studied the effects of Douglas-fir removal.
“Grasses and forbs under the oaks reestablished. Diameter growth on the oaks increased,” she said.
These research findings contributed directly to changes in policy that had previously limited land owners' ability to remove and sell conifers encroaching on oak woodland. The research also helped create new funding opportunities to support oak woodland restoration and conservation in Northern California.
Case study of oak woodland wildfire recovery
In July 2018, about two-thirds of the 5,289-acre UC Hopland Research and Extension Center was burned by the River Fire.
The transformation of the land, which had likely been without a large wildland fire for at least 100 years, was intense and stressful, said UC Cooperative Extension forest advisor Michael Jones. However, it also provided a unique opportunity for researchers to compare the impact of wildfire on the resiliency of vegetation on grazed and ungrazed oak woodland.
Jones established 35 one-fifth acre research plots at the research center and collected data two months following the fire and one year later. The research will continue in the future to better understand long-term impacts, but Jones was able to share revealing early results at the workshop.
Right after the fire, in severely burned areas areas, the future of the oaks looked ominous. Jones predicted 40% tree mortality.
“The oaks were exposed to persistent, intense heat. They were cooked,” he said. “But two months after the fire, we were already seeing basal sprouts. This was an amazing response by the trees. Oaks are pretty damn tough.”
A year after the fire, surveys showed that tree mortality in the burned areas was 25%, much less than Jones' early predictions. While some management for specific situations in severely burned areas may be necessary – such as removal of hazard trees, reducing fuels in defensible spaces or removal to control invasive species – the results of this work show the trees recover naturally.
“Esthetically, I know these systems aren't as pleasing as they were before, but ecologically, they are healthy and recovering,” he said. “In 100 years, it will look just as good as before the fire.”
Fire impacts in woodland areas previously grazed and not grazed
The fire on the research station also permitted Jones to compare the fire's differing impact on non-grazed and grazed oak woodland. At first, the grazed areas looked almost unscathed with minimal flame scorching on the bark, while an area where the pasture hadn't been grazed for 25 years had evidence of much higher severity fire.
“Grazing is a phenomenal way to help manage fuels,” Jones said. However, the grazed areas displayed ecological shortcomings a year later.
“In grazed pastures, the large mature trees were still alive, but there was no oak regeneration (basal sprouting or seedlings),” Jones said. “In the ungrazed area, a lot of biomass had been killed, but there's nearly 100% resprout of oak trees and we have an impressive amount of oak seedling recruitment.”
Jones said he isn't discouraging grazing.
“But it is important to protect sites from grazing, and especially wildlife browse, when a landowner or land managers' objectives are to regenerate or conserve oak woodlands,” Jones said.
New ambrosia beetle another threat to California oaks
Akif Eskalen, UC Cooperative Extension specialist in the Department of Plant Pathology at UC Davis, has identified a new insect-fungus team that causes oak borer wilt in Northern California Valley and Blue Oaks. It is an ambrosia beetle, commonly known as Mediterranean Oak Borer, which carries several fungi in its mouth. The beetle bores into the tree and introduces fungi to grow for food. The fungi spreads and disturbs the transportation of water and nutrients, causing wilt in the tree.
The oozing and staining lesions on the bark are similar to other oak fungal diseases, such as Sudden Oak Death. The beetle – native of Mediterranean basin countries in Africa, Asia and Europe – cannot fly far, so most likely is transported for long distances on infested firewood.
During the workshop, Eskalen suggested not moving firewood, removing heavily infested trees and chipping infested wood into 1-inch particles to reduce the spread of the ambrosia beetle and its fungal partner. He asked viewers to report any suspected oak tree infestations to the local agricultural commissioner, CDFA Diagnostic Laboratories, UC Cooperative Extension advisors or CALFIRE. Chemical options for sparing oaks from the ambrosia beetles' devastation are under investigation.
Threats to oaks and other native plants from root rotting Phytophthora
Restoration plantings have inadvertently introduced plant pathogens to native oak woodland ecosystems in California, said Ted Swiecki of Phytosphere Research, an organization that provides consulting services related to natural resource management, horticulture, urban forestry, and agriculture. The group of pathogens causing the damage are largely from the Phytophthora genus, first described in the 1860s. The name translates from Greek to “plant destroyer.”
Swiecki has observed when Phytophthora infested plants and soils are introduced to native habitats, the pathogens can attack various native plants, including toyon, madrone, manzanita and full-grown oaks. Once established, the pathogen can spread along drainages, by moving soil from one area to another and by hitchhiking on equipment, tires and hiking boots.
The pathogen can easily be overlooked at nurseries, which, by their nature, have conditions that favor Phytophthora development. Plants at nurseries are well watered, have high root density and are often placed on the ground where they can pick up pathogens.
He said the best approach to tackling Phytophthora is not using nursery stock for restoration or beautification of natural oak woodland. Direct seeding, using natural regeneration, or onsite propagation are safer ways to enhance vegetation in oak woodland.
“It's easier to prevent Phytophthora from being introduced in the first place and much cheaper and more effective than trying to eradicate it later,” Siewcki said.
- Author: Pamela Kan-Rice
Jones named UCCE forestry advisor
Michael Jones joined UCCE on Oct. 1, 2018, as the area forestry advisor in Mendocino, Lake and Sonoma counties. He specializes in forest entomology with a focus on forest health and integrated pest management of invasive and endemic forest pests.
Jones completed a Ph.D. in entomology from State University of New York, College of Environmental Science and Forestry and a B.S. in environmental biology and management from UC Davis.
Prior to joining UCCE, Jones was a graduate student and research project assistant at State University of New York. He developed and maintained research projects on delimitation, management, and biological control of the invasive forest pest emerald ash borer in New York. From 2010 to 2013, Jones was a research associate in the UC Davis Department of Entomology, in collaboration with the US Forest Service, Forest Health Protection in Southern California. He participated in a variety of forest pest research projects involving the detection, evaluation and management of endemic and invasive forest pests. He has been active in leading training activities for land managers and land owners in the field identification and management of forest pests, and training and supervising field crews in the collection of field data. As an undergraduate at UC Davis, he worked on sudden oak death with David Rizzo's lab group in the Department of Plant Pathology.
Based in Ukiah, Jones can be reached at (707) 463-4495 and mjones@ucanr.edu.
Sanchez named UCCE woody biomass specialist
Daniel Sanchez joined UCCE on Sept. 1, 2018, as a UC Cooperative Extension specialist in woody biomass utilization in the Department of Environmental Science, Policy & Management at UC Berkeley. Sanchez is an engineer and energy systems analyst studying the commercialization and deployment of energy technologies that remove CO2 from the atmosphere. Sanchez's work and engagement spans the academic, nongovernmental, and governmental sectors. As an assistant Cooperative Extension specialist, he runs the Carbon Removal Lab, which aims to commercialize sustainable negative emissions technologies, and supports outreach to policymakers and technologists in California and across the United States.
Sanchez earned a Ph.D. and a M.S. in energy and resources at UC Berkeley. He completed a B.S.E in chemical and biomolecular engineering at University of Pennsylvania.
Prior to joining the faculty of UC Berkeley, Sanchez was a AAAS Congressional Science and Engineering Fellow serving in the Office of Senator Michael Bennet (D-CO). He has previously held positions with the Advanced Research Projects Agency-Energy, Green for All, and the California Public Utilities Commission.
Sanchez is located in Mulford Hall and can be reached at (215) 593-4493 (cell) and sanchezd@berkeley.edu. Follow him on Twitter @Dan_L_Sanchez.
Larbi named UCCE ag application engineering specialist
Peter Larbi joined ANR on Aug. 13, 2018, as a UCCE area agricultural application engineering specialist at the Kearney Agricultural Research and Extension Center.
Prior to joining ANR, Larbi had been an Assistant Professor of Agricultural Systems Technology in the College of Agriculture at Arkansas State University since 2014. He developed an integrated teaching and research program related to agricultural systems technology; developed and managed research in precision agriculture, agricultural machinery systems, remote sensing and sensor technology; and provided service to the university, college, local community and general scientific community. Larbi held a joint appointment in the Division of Agriculture at University of Arkansas.
From 2012 to 2014, Larbi was a postdoctoral research associate at the Center for Precision and Automated Agricultural Systems at Washington State University. From 2011 to 2012, he was a postdoctoral researcher at the University of Florida Citrus Research and Education Center.
Larbi earned a Ph.D. in agricultural and biological engineering from University of Florida and a M.Sc. and a B.Sc. in agricultural engineering from Kwame Nkrumah University of Science and Technology in Kumasi, Ghana.
Larbi can be reached at (559) 646-6577 and palarbi@ucanr.edu.
Pyle joins Sierra Foothill REC grassland research team
Lysandra Pyle joined ANR on Aug. 15, 2018, as an assistant project scientist. Working closely with project directors at UC Sierra Foothill Research and Extension Center and Eastern Oregon Agricultural Research Center (EOARC), Pyle is leading a multistate research project investigating biotic and abiotic drivers of native grass recruitment on degraded intermountain rangeland and identifying potential management actions that can be used to improve large-scale restoration efforts.
Most of her field work and project development is being done from EOARC, which is in close proximity to the Oregon and California intermountain field sites.
Pyle completed a Ph.D. in rangeland and wildlife resources from University of Alberta, Canada, and a B.Sc. in biology from University of Regina, Canada.
Prior to joining ANR, Pyle worked on contracts specializing in biodiversity monitoring and rangeland ecology while finishing a Ph.D. in rangeland and wildlife resources at the University of Alberta, conferred in April 2018. From November 2017 to March 2018, Pyle was a vascular plant technician with Alberta Biodiversity Monitoring Institute (ABMI) at the Royal Alberta Museum. There, she identified vascular plants collected by ABMI technicians during the field season and contributed to publications.
Pyle also consulted as a plant community data analyst at Manitoba Forage and Grassland Association from January 2017 to March 2018, where she analyzed plant community data collected from the Aspen Parkland and Assiniboine Delta rangeland ecoregions, identified reference communities, and determined how they transition with disturbances such as grazing.
Her Ph.D. characterized the composition and diversity of grassland seed banks in two main studies: identified the diverse disturbance legacies and management histories of pastures on plant communities, seed banks, soils, and rangeland health, and examined legacy effects of pipelines on seed banks and biological soil crusts in native mixed grass prairie.
Pyle is based in Burns, Ore., and can be reached at (306) 551-1108 and lapyle@ucanr.edu. Follow her on Twitter at @GrasslandNerd.
Nathaniel Caeton was promoted to 4-H youth development advisor for Shasta, Tehama and Trinity counties on Aug. 1, 2018.
Prior to accepting his current position as 4-H youth development advisor, Caeton had served as the 4-H community education specialist since 2013. He was responsible for overseeing the daily operations of the 4-H Youth Development Program in Shasta and Trinity counties. During that time, he worked diligently to strengthen existing program relationships, while developing new relationships through outreach and collaboration. His master's work at CSU Monterey Bay combined multiple disciplines and built knowledge in the areas of learning theory, instructional design, instructional technology, interactive multimedia, assessment and evaluation. This enabled Caeton to plan, design, develop, implement and evaluate instructional programs. This work culminated in the creation of an electronic portfolio and capstone project, which involved the design and development of a one-hour e-learning module on diversity awareness for adult volunteers. He also actively volunteers with the Boy Scouts of America and the Civil Air Patrol.
Caeton earned an M.S. in instructional science and technology from CSU Monterey Bay and a B.A. in social sciences from CSU Chico.
Based in Redding, Caeton can be reached at (530) 224-4900 and nwcaeton@ucanr.edu.
Mahacek inducted into National 4-H Hall of Fame
Mahacek was one of 15 people inducted during the ceremony at the National 4-H Youth Conference Center in Chevy Chase, Md.
“We are proud to recognize the 2018 National 4-H Hall of Fame honorees for the passion, dedication, vision and leadership they have shown toward young people during their many years of service to 4-H,” said Jeannette Rea Keywood, National 4-H Hall of Fame Committee chair.
Mahacek joined a 4-H Club in Sonoma County when he was 10. During his 35-year 4-H career, Mahacek placed an emphasis on mechanical sciences and engineering projects. His work included development of curricula and activities in science processes, robotics, computers, GIS/GPS, bio-security and environmental issues, such as watersheds and wildlife habitats.
In 1988, Mahacek was a member of the team that developed the 4-H SERIES (Science Experiences and Resources for Informal Educational Settings) curriculum, which was funded by the National Science Foundation and Kellogg. SERIES was the first comprehensive pragmatic science education curriculum to join 4-H's traditional projects. In 2004, Mahacek served on the national leadership team for 4-H SET (Science, Engineering and Technology), a program that succeeded SERIES. Now known as STEM (Science, Engineering, Technology and Math), the project aims to enhance young people's interest in developing the knowledge and skills needed for the 21st century's technically oriented careers.
The crowning achievement of his career was the development of the 4-H Junk Drawer Robotics curriculum in 2011. The curriculum shows how to engage children in building robotic devices with rubber bands, Popsicle sticks, medicine dispensers and bamboo skewers – the kinds of things people already have around the house. The robotics program develops skills that go beyond science and engineering. The children learn communications, teamwork and critical thinking.
Junk drawer robotics is one part of a three-track robotics curriculum. The other tracks are virtual robotics, in which participants build virtual robots on computers, and robotics platforms, which employs commercial robot building kits for materials. The package of robotics programs was the No. 1 selling 4-H curriculum in the nation in 2011. Mahacek was also a driving force in the community in founding the UC Merced Engineering Service Learning Program Castle Science and Technology Center. This facility used a former US Air Force facility to provide hands-on science experiences to the youth of the county.
Mahacek received many honors for his contributions to 4-H and UC Cooperative Extension. In 1988, he received distinguished service awards from the state and national 4-H associations. The Merced County Farm City Ag Business Committee presented him its Agri-Education Award in 1992. Mahacek received the “Hands-On Heroes Award” at the Merced County Children's Summit.
Mahacek said the 4-H program has evolved during his tenure, but it has not changed its core objectives.
“We went from being a predominantly ag program to including many other topics. Our members used to live in just rural settings, but now they come from the suburbs and urban neighborhoods,” Mahacek said. “But we're still promoting the concept of working together and gaining confidence by learning practical skills.”
The National 4-H Hall of Fame honorees are nominated by their home states, National 4-H Council, the National Association of Extension 4-H Agents or 4-H National Headquarters/National Institute of Food and Agriculture based upon their exceptional leadership at the local, state, national and international levels.
Wilen recognized for contributions to nursery industry
Cheryl Wilen, area IPM advisor based in San Diego County, was presented the Research Award by the California Association of Nurseries and Garden Centers (CANGC) for her contributions to the nursery industry at the CANGC Convention in San Diego on Oct. 10, 2018.
“This award acknowledges Dr. Wilen's many significant contributions over her career that have benefited the California nursery and landscape industry,” said Loren Oki, UCCE environmental horticulture specialist in the Department of Plant Sciences at UC Davis and co-director of UC's Nursery & Floriculture Alliance, who presented the award to Wilen.
Wilen specializes in Integrated Pest Management (IPM) for ornamental plant production and maintenance in nurseries, greenhouses, field production, floriculture, turf and landscape, which has resulted in the use of pesticides in a more prescriptive manner and the development of alternative strategies to more efficiently control pests of ornamental plants. Although her primary research focus is the management of weeds, snails and slugs, her other areas of research include the Asian citrus psyllid, disease management in floricultural crops, nematode management in tomatoes, invertebrate pest management in nurseries, vertebrate pest management, mitigating pesticide contamination in surface water runoff, and soil solarization.
Wilen also recently received the UC ANR Distinguished Service Award for leadership. She has served ANR as the acting and interim director of the Statewide UC IPM Program, leader of the Endemic and Invasive Pest and Disease Strategic Initiative, member of Program Council, organizer of the Pest Management Coordination Conference, chair of several UC ANR search committees, and chair and member of the South Coast Research and Extension Center Research Advisory Committee.
Her current and previous professional service includes chair of the Basic Science Section Western Society of Weed Science, chair of Teaching and Technology Transfer Section Weed Science Society of America, chair or co-chair of meetings of professional organizations including the California Weed Science Society, and has served or is currently serving as a member of various committees of the Weed Science Society of America, Southern California Chapter of the California Association of Pest Control Advisers, Steering Committee of the 2015 International IPM Symposium, and the CANGC Research Advisory Committee.
The CANGC Research Award recipient is selected by their peers and colleagues from industry and academic community.
4-H teams bring home NAE4-HA awards
Katherine Soule, UC Cooperative Extension director and youth, families and communities advisor for San Luis Obispo and Santa Barbara counties, and community educators Janelle Hansen, Andrea Hollister, Laura Pena, Dagmar Derickson, Shannon Klisch, Melissa LaFreniere, Yezenia Romero, Yudilia Tomsen, Miguel Diaz, Betsy Plascencia, JaNessa Willis and Lisa Paniagua won the Excellence in Healthy Living Programming Award for the Western Region. The team also won the NAE4-HA Excellence in Healthy Living Programming for California. The Excellence in Healthy Living Programming Award recognizes outstanding efforts and impacts of NAE4-HA members in healthy living programming, evaluation, and/or research projects.
JoLynn Miller, UC Cooperative Extension 4-H youth development advisor for the Central Sierra, won Excellence in 4-H Volunteerism Award for the North Central Region. Miller was part of a team with members from the North Central Region that created the National 4-H Volunteer E-Forum.
At the state level, Kendra Lewis, academic coordinator; Sheila Bakke, 4-H program representative in Solano County; Gloria Gonzalez, 4-H SET program representative, Valerie Williams, 4-H program representative, and Shannon Horrillo, statewide 4-H Youth Development Program director, won the 4-H Military Partnership Award
The purpose of the 4-H Military Partnership Award is to recognize the individual or team who has created a positive Extension image through his/her/their leadership and citizenship as it relates to the development of the 4-H Military Partnerships on U.S. Army, U.S. Air Force, and/or U.S. Navy installations and in the community as it pertains to Reserve Component service members and families.
John Borba, 4-H youth development advisor for Kern County, was honored with the 25 Years of Service Award, Steven Worker, 4-H youth development advisor for Marin, Sonoma and Napa counties received the Meritorious Service Award for service in 4-H programs for 15+ years. Charles Go, UC Cooperative Extension 4-H youth development advisor for Alameda and Contra Costa counties, received the Distinguished Service Award for more than 7 years of service. Go also has begun serving as western regional director on the NAE4-HA Board. Soule received the Achievement in Service Award for 3 to 6 years of service in 4-H programs.
They received the awards Oct. 10 at the National Association of Extension 4-H Agents conference in Columbus, Ohio.
Verdegaal inducted to San Joaquin County Agricultural Hall of Fame
Paul Verdegaal, who retired after serving more than 30 years as UC Cooperative Extension viticulture advisor in San Joaquin County, was inducted into the San Joaquin County Agricultural Hall of Fame on Oct. 18. Donald Rough, who was a UCCE pomology advisor, will be inducted posthumously.
“Verdegaal helped remove the stigma that Lodi could not grow premium wine grapes through exhaustive research, leadership and work with growers,” wrote Bob Highfill, marketing and communications manager for the Lodi Winegrape Commission, in the Stockton Record.
“During Verdegaal's tenure as farm advisor, the grape and wine industry in San Joaquin County flourished. Thirty years ago, there were 43,370 acres of grapes cultivated in San Joaquin County. In 2017, there were close to 100,000 acres. In 1986, Lodi was first recognized as an American Viticulture Area, but many, including the University, still felt that premium wine varietals could not be grown commercially in the Valley. Verdegaal worked hard to change that stigma.”
Kabashima honored with Urban Tree Legacy Award
Kabashima's varied research and extension programs have included the management of insects, diseases, and biological control of exotic and invasive pests.
Kabashima, who retired in 2015 after 28 years of serving the nursery and landscape industry and homeowners in Orange and Los Angeles counties, continues to lead the battle against invasive shot hole borer pests that spread fusarium dieback, threatening trees in Southern California. On Oct. 3, Kabashima gave a presentation at an urban forest summit for public agencies, reviewing current pest concerns relating to trees for San Diego County and what the county needs to do to defend against future invasions.
He has provided testimony for the California Legislature to fund further research into these destructive pests. In January, Kabashima was instrumental in bringing together university scientists, federal and state government representatives, county agricultural commissioners and nonprofit organization leaders for a summit in the state capitol to coordinate their efforts to battle invasive pests.
Kabashima received his bachelor's degree in agricultural biology from Cal Poly Pomona, master's degree in pest management from UC Riverside, an MBA from Pepperdine University and a doctorate in Entomology from UC Riverside. In 2014, he was inducted into the Green Industry Hall of Fame, and in 2016 he received the Arboriculture Research Award from the Western Chapter of the International Society of Arboriculture.