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Posts Tagged: Climate Change

How will climate change affect Southern California?

Plants regrow on a landscape scorched by the Thomas Fire of 2017. Photo by Annemiek Schilder

UC Thelma Hansen Fund to host climate webinar series, April 27-29 

Members of the public are invited to attend a free webinar series discussing the effects of climate change on Southern California. At the three-day webinar Climate Change: What Does It Mean for Southern California?, UCLA climate scientist Daniel Swain and UC Agriculture and Natural Resources scientists will discuss climate changes anticipated, impacts on agriculture, wildfire risk and how to prepare for it, and ways to communicate about climate and to build resilience in communities.

“We are hearing a lot about climate change, but it can be difficult for the average person to figure out what it means for where they live and to understand the science behind it,” said Annemiek Schilder, director of UC Cooperative Extension in Ventura County and UC ANR Hansen Agricultural Research and Extension Center.

Topics of discussion include drought, adaptation for agriculture, fire management on rangelands and wildland-urban interface areas, and how UC Climate Stewards might improve climate understanding and empower community-level stewardship.

“All of us need to be better informed about this new reality and know how to respond to it,” said Schilder, who is organizing the event. “For Southern California, as a region with intense agricultural production and huge urban populations living in proximity to the coast, climate change could have devastating impacts. One of my favorite Latin sayings applies: Serius est quam cogitas – it is later than you think!”

Although residents may be concerned about climate change, they may not know what to do. The scientists will offer suggestions.

“People may feel powerless in the face of something that is happening on a global scale, but there are indeed things that can be done by individuals to mitigate the effects and to build resilience in the face of small and large disasters,” Schilder said. “In fact, doing nothing has a huge cost associated with it. Think of the economic damage already incurred by climatic extremes in recent years and the costs associated with possible future waves of climate refugees coming to the U.S.” 

Registration for the webinar series, which is sponsored by the UC Thelma Hansen Fund, is free. To register and see the agenda and speaker biographies, visit

Speakers include 

  • Daniel Swain, Ph.D., climate scientist, UCLA Institute of the Environment and Sustainability – Climate Change in California: A Drier or Wetter Future—or…Both?   
  • Sarah-Mae Nelson, M.S., UC Climate Stewards academic coordinator – UC Climate Stewards: Fostering Resilience in California Communities and Ecosystems
  • Tapan Pathak, Ph.D., UC Cooperative Extension specialist in climate adaptation in agriculture, UC Merced – Climate Change Trends and Impacts on Agriculture in California and Ventura   
  • Ben Faber, Ph.D., UCCE soils, water and subtropical crops advisor, Ventura County – Heat, Wind, Freeze, Wind, Repeat 
  • Nicki Anderson, UCCE community education specialist, Ventura County – Overview of the Healthy Soils Program
  • Max Moritz, Ph.D., UCCE wildfire specialist, Bren School of Environmental Science & Management, UC Santa Barbara – How Can We Address the Growing Wildland-Urban Interface Problem in California?  
  • Matthew Shapero, M.A.,UCCE livestock and range advisor, Ventura and Santa Barbara counties – Fire and Rangelands: Impacts on Ventura County Livestock Agriculture Counties  
  • Sabrina Drill, Ph.D., UCCE natural resources advisor, Ventura and Los Angeles counties – SAFER, Sustainable and Fire-Resistant Homes & Landscapes  


Posted on Tuesday, April 6, 2021 at 10:25 AM
Focus Area Tags: Environment

Lush urban forests can help communities face climate change

Urban trees are much more than lovely greenery and stately landscape features. Scientists believe trees are a key tool for combating climate change and living with warming temperatures in California.

UC Cooperative Extension is bringing together municipal and nonprofit organizations, homeowners associations, contractors, the green industry and educators to increase the tree canopy in urban areas by planting recommended species. Nearly 200 people gathered online in March 2021 to share research results, accomplishments and tree canopy growth strategies at the “Trees for Tomorrow Start Today” workshop.

“We need to act now and together to build community forests,” said Janet Hartin, UCCE area environmental horticulture advisor in Southern California and the event organizer. “This is the time to talk about challenges and opportunities for a healthier tomorrow. As our cities grow, so do associated urban heat islands like asphalt-covered parking lots and streets.”

For decades, temperatures have been rising across the planet. While governments work worldwide to reduce carbon dioxide and other emissions that contribute to the greenhouse gases warming the earth, trees are a particularly effective way to make a significant impact on the problem at the local level.

“With proper placement around homes, trees can reduce home energy cost by 30 to 50 percent,” Hartin said. “Treeless urban parking lots can be 20 to 25 degrees hotter than park-like settings in the same area.”

Trees beautify and cool a boulevard in Palm Springs. (Photo: Pixabay)

Trees have myriad additional benefits. They provide cooling shade to sidewalks, schools and shopping centers. Trees remove dust from the air, create windbreaks, capture runoff, reduce glare, muffle urban noise and provide a habitat for birds and other animals. In the process of photosynthesis, trees also absorb and store carbon dioxide, helping reduce greenhouse gas emissions to the atmosphere.

With so many reasons to plant and maintain trees in urban communities, and with the overarching threat of climate change, there's no time to waste in nurturing lush green canopies in California cities, schools, parks and neighborhoods. Hartin said ensuring the proper tree selection, placement and care is critical.

“Trees improperly selected or not properly cared for are taking precious time away from the future benefit of trees,” she said.

UC conducts long-term research to identify the best urban trees

Hartin is working with a team of UC Agriculture and Natural Resources and U.S. Forest Service scientists to identify the best drought- and heat-tolerant trees for different areas of the state. Six years ago, the team vetted 100 trees native to California, the Southwest and Australia, taking into account habitat, physiology and biological interactions. A selection of fast-growing, drought-, heat- and pest-resistant species were planted at UC Riverside, the UC South Coast Research and Extension Center in Irvine and in Northern California to be evaluated over 20 years. In addition, Hartin has a subset of trees in a ‘mulch, no mulch' study at Chino Basin Water District in Montclair.

Trees in UC ANR's 'mulch, no mulch' study in Montclair.

“We're beginning to see the best performers in those areas,” said Hartin, who shared a few of the tree species that have already caught her fancy.

Island Oak (Quercus tomentella) – A disease-resistant evergreen California native adapted to many Sunset magazine zones and soils.

Netleaf Hackberry (Celtis laevigata var. reticulate) – A deciduous tree with small red berries that attract birds. “This is performing beyond our expectations,” she said.

Thornless Honey Mesquite – (Prosopis glandulosa ‘Maverick') – Native to the Southwest U.S., the tree is heat tolerant and cold hardy. It grows as wide as it is tall – about 35 feet.

Pistacia ‘Red Push' (Hybrid of Pistacia atlantica × Pistacia integerrima) – Developed in Arizona, the tree grows 20-feet tall. “The foliage makes you think of Maine or Minnesota in the fall, but this tree has a brilliant red tinge when it first leafs out in the spring,” she said. “It's performing really well in our studies.”

Bubba Desert Willow (Chilopsis lineraris ‘Bubba') – “My favorite tree from our study,” Hartin said. “It grows fast, has beautiful trumpet-like flowers and requires little maintenance.”

Trees in a UC ANR study in which irrigation was turned off three years after establishment.

Hartin recommends finding more details about these and other trees at Read more about the project here: UC study seeks street trees that can cope with climate change.

UC Master Gardeners provide advice on tree selection and maintenance

Proper location based on climate zone and specific conditions around one's home, planting and maintenance are important for tree longevity. Helpful information and support is available throughout California from UC Master Gardener Program volunteers.

Mandy Parkes of the Inland Empire Resource Conservation District said Master Gardeners are a “pivot point” for successful tree planting. She spearheaded a tree planting program in North Redlands that involves partnerships with the California Climate Action Corps, the city, ESRI, University of Redlands and UCCE to encourage residents to plant trees where the urban canopy is currently low.

“New tree owners need long-term support to aid selection and placement of trees,” Parkes said. “Master Gardeners can weigh in on yard design, irrigation and most importantly, guiding trees into the ground and caring for them correctly and in a way that works for the residents.”

Studies have shown that there is often less tree canopy cover in lower-income communities. In many under-served neighborhoods, canopy cover ranges from 0 to 11%, Hartin said, far short of the recommended 25% canopy cover.

“In wealthier neighborhoods, there tends to be higher canopy cover, and in addition, in those areas there is less asthma and cardiovascular disease,” Hartin said. “Encouraging planting in low-income neighborhoods is one of our goals.”

Andy Lyons, program coordinator for UC ANR's Informatics and GIS Statewide Program and a workshop participant said, “GIS technology and data offer exciting new possibilities for managing our urban trees, including the ability to create highly accurate maps of urban trees from aerial imagery, mobile data collection apps to monitor tree health, and the ability to overlay climate change projections for species selection and planning."

Tree failure due to improper irrigation.

Threats to urban trees

Threats to trees were also discussed at the day-long Trees for Tomorrow meeting. West Coast Arborists' Cris Falco said he is frequently dismayed to see poorly pruned trees. “In my opinion, poor tree work is still the rule, not the exception,” he said.

A common mistake is cutting back, or heading, branches, while the goal should be a natural system of pruning to retain and promote characteristic growth. But, with 90% of the urban forest grown on private property, all too often poor tree architecture or inferior branch structure can lead to early tree failure. Falco and other speakers recommended regular pruning by a certified arborist.

Insect pests and diseases can also get in the way of long-term tree survival. Dave Rogers is a recently retired city arborist and currently acting director of the Community Services Department in Claremont, a college town in eastern Los Angeles County known as the “City of Trees and Ph.D.s.” He said the polyphagous shot hole borer reached Claremont and threated to kill heritage oaks and sycamores. Rogers gathered information and shared it with the city council, who provided $300,000 to treat infested trees. “The treatments worked,” he said.

But the pest continues to threaten trees in Los Angeles and Orange counties. One of the promising trees in the Trees for Tomorrow climate study, the Thornless Desert Museum Palo Verde, was found to be susceptible to shot hole borer, so experts are not recommending residents plant this tree.

Another pest, the ash borer, is in Eastern Texas and Boise Idaho, and will likely make its way to the West Coast eventually, said plantsman and workshop participant Nicholas Staddon of Everde Growers.

“It will kill every single ash tree we have,” said Staddon, who was a plant specialist at Monrovia Wholesale Nursery for many years. “We have to look at a broader diversity of trees. From the growers' perspective, trees are the most expensive items we grow. People who want to buy trees need to have some financial skin in the game for growing them.”

Making trees that are climate-tolerant but less common available to the public at nurseries is another hurdle. Nurseries carry what people are asking for, but people don't always know about tested species and even older, “tried and true” varieties.

“We have a list of trees adapted to the climate that are water wise, but at this point, it is difficult to find those in the nurseries,” said Debby Figoni, UC Master Gardener and water administrator for City of Beverly Hills. “It's one thing to know what you're supposed to plant. It's another to find that tree. We have to give people resources.”

The rich discussion regarding the need to enhance tree canopies with recommended species and proper long-term care did not end at the conclusion of the workshop, Hartin said.

“A goal of the workshop was to identify ways to work together more effectively across professions,” she said. “Lots of great ideas came out of the roundtable discussions that we'll be following up on. These include providing education on proper tree selection and care through local task forces consisting of members of the nursery and landscape industry and regular communication between these groups.”

Posted on Wednesday, March 17, 2021 at 9:25 AM
Focus Area Tags: Environment

'Climate Change' May Be a Key Factor in Declining Butterfly Populations

Edith’s checkerspot (Euphydryas editha) is one of the species declining in at least two datasets quoted in the Science publication. (Photo courtesy of Walter Siegmund, Wikipedia)

The public tends to blame habitat loss and pesticides for the declining butterfly populations in the Western United States. But climate change, aka...

Edith’s checkerspot (Euphydryas editha) is one of the species declining in at least two datasets quoted in the Science publication. (Photo courtesy of Walter Siegmund, Wikipedia)
Edith’s checkerspot (Euphydryas editha) is one of the species declining in at least two datasets quoted in the Science publication. (Photo courtesy of Walter Siegmund, Wikipedia)

Edith’s checkerspot (Euphydryas editha) is one of the species declining in at least two datasets quoted in the Science publication. (Photo courtesy of Walter Siegmund, Wikipedia)

UC Davis distinguished professor Art Shapiro monitoring butterfly populations along Gates Canyon Road, Vacaville. This image was taken Jan. 25, 2014. (Photo by Kathy Keatley Garvey)
UC Davis distinguished professor Art Shapiro monitoring butterfly populations along Gates Canyon Road, Vacaville. This image was taken Jan. 25, 2014. (Photo by Kathy Keatley Garvey)

UC Davis distinguished professor Art Shapiro monitoring butterfly populations along Gates Canyon Road, Vacaville. This image was taken Jan. 25, 2014. (Photo by Kathy Keatley Garvey)

Posted on Friday, March 5, 2021 at 1:45 PM
Focus Area Tags: Environment, Health, Yard & Garden

UC Climate Stewards take action to protect communities

One action Climate Stewards propose to save water in the desert is to replace turfgrass with native plants if the area is not used for recreation. Photo by Elizabeth Ogren Erickson

Water availability, food production and biodiversity are being affected by climate change. There are actions individuals can take to protect their communities. Climate Stewards is a new public education and service effort by the University of California Agriculture and Natural Resources designed to improve climate understanding and empower community-level stewardship.

The first group of certified UC Climate Stewards graduated in December from the 40-hour course taught by Cameron Barrows, UC Riverside research ecologist in the Center for Conservation Biology, at the UCR Palm Desert campus.

“I am already using what I learned!” said Elizabeth Ogren Erickson, who was one of 32 participants in the inaugural UC Climate Stewards course led by Barrows. “Two Coachella Valley organizations contacted me in December, requesting that I speak to their organizations virtually.” She is preparing a presentation that describes the climate crisis and offers some climate resilience solutions. 

The Climate Stewards course is delivered through a collective impact network – organizations with common goals, but with unique strengths and strong local connections. To reach a variety of audiences, the organizations tailor the course content and delivery to be culturally relevant and address local needs and priorities. Each participant completes a capstone project as part of the certification process.

Ogren Erickson and her husband Robert Erickson, who took the course with her, assessed landscaping in their neighborhood for their capstone project. Based on their findings, they have proposed landscape changes to their homeowners association. For example, to save water, they propose converting turfgrass areas that are not used for recreation to native plants.

“Did you know that one square foot of turfgrass, on average, requires 73 gallons of water per year, whereas one square foot of desert landscaping, on average, requires only 17.2 gallons of water per year?” she asked.

Hot spot in Coachella Valley

Cameron Barrows interviews Randy Buckmaster for the Climate Stewards Palm Springs windmill tour. Colin Barrows and Tracy Bartlett shoot video for the virtual field trip. Photo by Elizabeth Ogren Erikson

“The Coachella Valley is warming faster than the rest of the planet,” said Barrows, explaining local interest in the program. “The desert community is feeling the effects more rapidly than other places. Scientists say the average desert temperature increase is already above 4 degrees C. Only the arctic is warming faster.

Greg Ira, director of the UC California Naturalist Program, who oversees the new course, said, “The UC Climate Stewards certification course is a first step in a long-term project in which our partner organizations delivering the course will try to improve community resilience to climate change and ultimately measure that change.” 

To build their community's resilience to climate change, UC Climate Stewards are encouraged to engage in community-scale efforts, including volunteer service that draws on the knowledge and skills gained from the course. These may include conducting community education and outreach, participating in local adaptation planning efforts, facilitating community and participatory science projects, or addressing issues of environmental or climate justice.

During the course, participants read Climate Stewardship: Taking Collective Action to Protect California written by Adina Merenlender, UC Cooperative Extension specialist, and Brendan Buhler. Rather than a reference text, the book is a collection of stories from diverse voices and shows how specific actions enhance the resilience of communities and ecosystems across California's distinct bioregions.

Together, UC Climate Stewards academic coordinator Sarah-Mae Nelson, Merenlender and Ira form the core UC ANR team who have partnered with local organizations, other UC experts and practitioners around the country to design and move the course forward.

“The program differs from many other climate education efforts because it goes beyond the science of climate change to address the social and emotional challenges climate change presents,” says Nelson. Participants also explore root causes and environmental justice issues. They learn to communicate about climate change and leverage community and state resources to advance collective solutions.

“There are components of the training that are gut-wrenching, like an assignment that relives a personal experience with climate extremes, such as flooding or landslides, and yet every segment of the training is important for each of us to learn, whether an elementary, middle school, high school, or adult education student,” Ogren Erickson said.

While the course was planned to include field trips, because it launched in October amid coronavirus restrictions, Barrows gave the students a tour of a local solar panel construction firm and wind energy site via video.

Measuring community resilience

Serving plant-based foods, sourcing locally and reducing food waste are among the criteria UC Climate Steward Tamara Hedges uses to evaluate restaurants. Photo courtesy of Chef Tanya’s Kitchen in Palm Springs.

Before teaching the UC Climate Stewards course, Barrows and one of his co-instructors, Tamara Hedges, the executive director of UC Riverside Palm Desert Center, conducted a baseline community resilience assessment.

The assessment tool – developed by the Community Resilience Assessment Organizations – examines 26 indicators of community resilience in four broad categories: basic needs, environment and natural systems, physical infrastructure and community connections and capacity. They will rank specific actions, for example, reducing food waste at restaurants. Like all Climate Stewards partners, the UC Riverside Palm Desert Center team will repeat the assessment every year to identify changes over time.  

To launch UC Climate Stewards, UC ANR collaborated with existing partner organizations from the California Naturalist certification course. To expand the program, they are seeking new partners from a wide range of organizations that have training capacity and an interest in addressing climate change at the community level. Current UC Climate Stewards partners include:

American River Conservancy

Coastal Training Program - National Estuarine Research Reserves

Columbia College

Community Environmental Council

Community Nature Connection

Conservation Society of California - Oakland Zoo

Pacific Grove Museum of Natural History

Pasadena City College

Pepperwood Preserve

Point Reyes National Seashore Association

Riverside-Corona Resources Conservation District

Santa Clara County Parks

Sierra Streams Institute

Sonoma Ecology Center

UC Hopland Research and Extension Center

UC Riverside Palm Desert Center

USC Sea Grant

The UC Climate Stewards course is currently being offered online throughout California, but will shift to a hybrid “online and in-person” delivery format when appropriate. For more information about the UC Climate Stewards, and to find a course near you, visit

Posted on Thursday, February 25, 2021 at 11:51 AM
Focus Area Tags: Environment

Forest management can help giant sequoias and coastal redwoods survive

In 2020, 9,000 fires scorched more than 4 million acres of California, a record-breaking year, reported Alejandra Borunda in National Geographic. Fires burned through homes and oak forests, grasslands and pines — and also through patches of giant sequoias and coast redwoods, respectively the most massive and the tallest trees on earth.

Giant sequoias are not the oldest living trees, but some have been growing in Sierra Nevada forests for more than 3,200 years. They are found in 68 groves on the Sierra's western flank. The state's redwood forests grow in a narrow strip along the coast of Northern California and Southern Oregon.

The 2020 fires burned through about 16,000 acres of sequoia groves, about a third of their total area. In redwood forests of the Santa Cruz Mountains, 40,000 acres burned.

But because redwoods are well-adapted to fire, they'll likely recover pretty quickly, said Scott Stephens, a UC Berkeley fire scientist. “In some ways, this fire could make redwoods more dominant in the landscape," he said, because other trees — like the hardwoods or Douglas firs that crowded the local forests — died outright in the burns.

However, scientists are concerned one cause of the fires, climate change, could have additional impacts on these natural treasures.

Since the mid-1800s, temperatures in the western U.S. have increased by 1.6 degrees Fahrenheit. Fog banks are fading in coast redwood territory, and snows are less consistent in the Sierras. The changes leave redwoods and sequoias without their preferred climate conditions.

The most responsible thing to do now, Stephens said, is to “take the opportunity that has been handed to us,” and make a plan to go back in and burn again—soon, within the next few years.

UC Cooperative Extension forestry advisor Lenya Quinn-Davidson agrees that California must manage fire to help the trees survive. Tree-ring records show that humans have influenced the fire regime for better and worse as long as they've been in these forests.

“The empowering message there is, human management can actually override the effects of climate in a fire contest,” Quinn-Davidson said. “It's not just a climate story. We can't just throw in the towel, feel overwhelmed, and tell ourselves these trees are done for. That's not true!”

Towering coastal redwoods frame a Northern California highway. (Photo: Wikimedia Commons)
Posted on Thursday, January 7, 2021 at 10:33 AM
Focus Area Tags: Natural Resources

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