Jacob Margolis
covers science, with a focus on environmental stories and disasters, as well as investigations and accountability.
Published August 1, 2023 7:26 AM
The Desert Museum Palo Verde doesn't provide as much shade as other trees, but it sure is beautiful.
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Jacob Margolis
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LAist
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Topline:
L.A.’s urban forest was established during a time when water seemed plentiful and climate change was barely a footnote in scientific journals. Now, it’s being threatened.
The experiment: There’s an experimental plot at UC Riverside where trees are being tested for their resilience to hot and dry conditions so that we have a better idea of what might do well as climate change worsens.
The results: The tests are expected to continue another decade, but so far trees including the red push pistache, the desert willow and the honey mesquite appear to be doing well.
The failures: The Texas live oak’s not looking too good in scorching hot riverside, but is apparently doing well in test plots in the more temperate coastal areas.
On a recent triple digit summer day, I made my way out to a dusty field at UC Riverside, the research center of California’s citrus universe.
The UC Riverside Citrus Research Center is lined with row after row of citrus trees. It's also home to the Climate Ready Tree test plot.
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Row after row of tangerines, oranges and pomelos —11,000 in total — baked under a heat dome. Off in the distance, wildfire smoke passed in front of the San Bernardino Mountains, which had been covered in thick snow just a few months ago.
The dusty field is just one of the many plots that the university uses to trial new trees, grow budwood for distribution and come up with solutions for devastating problems like Huanglongbing, a bacteria driven greening disease that’s threatening trees world wide.
However, I was there to check out a block of 48 trees sitting along a fence that look nothing like the thousands of citrus around them. Inconsequential at first glance, you could easily imagine them along any road in Los Angeles, but that’s kind of the point. The trees are being tested to see if they can survive our hellishly hot and dry future driven by climate change.
Where, how and why these trees are being tested
There are 12 different types of trees and four of each at the UC Riverside test plot.
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It’s a collection of 12 different species — four of each — pulled from around the world and being run through the gauntlet by the U.S. Department of Agriculture. Planted seven years ago, they were given supplemental water to help them get established, but since then they’ve had to survive on their own through record-setting heatwaves and drought years.
The Texas, or escarpment, live oak was struggling and nearly dead at the UC Riverside plot. It's reportedly doing better at a plot along the coast.
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The trees are being assessed for a number of factors including attractiveness, whether they provide good shade, how much work it takes to maintain them (less pruning means lower maintenance costs) and whether they can survive without much water.
The experiment is expected to run for at least 20 years, but visit the plot today and it's clear which trees are thriving. Surprisingly, just because a tree comes from a hot climate doesn’t mean it’s going to do well.
“What kind of choices are we going to be able to make in the future?,” said Natalie van Doorn, U.S. Forest Service scientist and co-creator of the experiment known as Climate Ready Trees. “Are we going to have enough water to make that decision that yes we want to keep watering our trees?”
If not, we’ve got to have viable candidates that we know will thrive and provide critical tree cover, which for residents, can be a matter of life or death.
Why L.A.'s hundreds of thousands of trees matter so much
Trees are an absolutely critical part of our infrastructure. They have a marked impact on human and ecosystem health.
The red push pistache had one of the densest canopies at the test site.
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Trees can:
Help drop temperatures in urban areas by as much as 45 degrees
Reduce energy use
Suppress noise
Improve air quality
Sequester water
Help provide homes to all sorts of creatures, all according to the Environmental Protection Agency.
Which is why any sort of major threat to the more than 700,000 street trees planted across the city of L.A. is of major concern, and that's what climate change is doing.
Much of our urban forest, as it’s known, was planted over the past 100 years as the region developed. As people migrated from other parts of the country they often wanted to plant the trees that they were familiar with, though that could mean species from wetter climates.
The sweetgum tree, whose spiky seed balls you’ve likely stepped on while walking through a park, is a decent example. It’s originally from the eastern area of the country and doesn’t love drought conditions, thriving in the moist soils of the Mississippi Delta. More than 25,000 of them are planted across the city, according to a tree inventory.
A red pistache
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Jacob Margolis
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The flowers of the desert willow are a beautiful pink.
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“I think in general, many of urban forests contain what I would call legacy plantings that occurred after World War II, when people were building homes and moving in and planting trees. And so those trees now, maybe 40, 50, 60 years old, they were planted when water was abundant. They've grown accustomed to having water and of course they're not necessarily as well adapted to hot dry conditions,“ said Greg McPherson, retired research scientist with the U.S. Forest Service, and one of the creators of the experiment.
We were long able to satisfy a broad range of moisture requirements because we imported and dumped all but unlimited gallons of water all over our landscapes, often in an effort to keep our lawns green.
That is until this past decade, when drought and water cuts became the norm.
What happens to water-stressed trees
The flowers of the maverick mesquite.
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The flowers of the desert museum palo verde.
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Water-stressed trees are more susceptible to pathogens and insect attacks, and are, predictably, more likely to die than healthy happy trees. One only need look to the Sierra Nevada to understand how bad things can get. More than 100 million trees have died over the past decade in part due to drought stress.
There are no clear mortality estimates for LA’s urban forest over the past decade, so we can’t say whether extreme conditions have led to more tree deaths in our area. And unless we had a widespread, granular tree tracking program, it’s going to be tough to determine why an individual tree is lost.
There are hundreds of thousands of street trees across the city, and urban trees face all sorts of challenges trees in our forests don’t. Yard tools can damage them and lead to the introduction of disease, poor pruning practices can lessen tree resilience and sometimes people just cut them down because they want to redo their yards.
That said, conditions are becoming more challenging for our urban forest and we could be on the path to greater die off as a result. Longer, more sustained droughts are becoming more common, meaning less water for irrigated landscapes, and more extreme heat days mean trees require more water to survive.
While this palo blanco, originally from northern Mexico, was looking OK, another one was struggling substantially.
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Odds are we haven’t seen the worst of it. Even though we’ve had a handful of water cuts over the past decade, lawns are still green and trees still often getting supplemental irrigation.
Given how bad cuts got before this wet year, it’s easy to imagine a point where outdoor watering is limited to the point that lawns start to finally die off and the trees that rely on that same supplemental water start to die too.
“The roots of those trees are near the surface because turf is irrigated in frequent, but not heavy doses. So the water stays in the upper surface of the soil and that’s where the roots are,” McPherson said.
Depending on the variety, trees can take decades to become established and provide meaningful shade. If we’re planting something today with the expectation that it’ll survive in the lawn-less future we’re charging towards, it’s important to find species that can thrive on minimal supplemental inputs.
Our need for more resilient trees
McPherson’s efforts to find what the experiment is calling ‘climate-ready trees’ began about two decades ago, when he recognized what the existential threat of warming trends could mean for our urban forests.
The Desert Museum Palo Verde doesn't provide as much shade as the other trees, but it's nice to look at and likes hot weather.
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“I began in 1999 when I got a 18 wheeler full of desert trees from Arizona shipped up and planted them all around Sacramento and Davis, and really started evaluating their performance,” said McPherson.
Some, like the Palo Verde, even though it can thrive in hot climates, struggled.
“It just grew so fast that the top would outgrow the roots and it would blow over in our wind,” he said. “Some of them worked, some didn’t. But that led to the idea that we need to evaluate more species”
The rosewood tree had a sizable canopy that provided good shade.
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In 2015 he and van Doorn got a grant to begin trialing trees at a test site at UC Davis, and eventually along the coast in Irvine, and in the scorching hot environment of Riverside.
So which trees have been thriving?
Though the experiment still has a number of years to go, I made the trip to the Riverside plot because out of the two Southern California plots, I wanted to see which trees were doing the best in the most extreme conditions.
Many were thriving, but three stood out because they looked healthy, cast wonderful shade and were quite attractive. They’d be wonderful along any street.
The Red Push Pistache was the first to catch my eye in part because it had one of the thickest canopies and beautiful leaves. It’s originally from Arizona.
The red push pistache seemed to be thriving.
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The canopy of the rosewood, originally from India, rivaled the pistache and the Desert Willow, native to the southwest, put out gorgeous pink flowers.
A rosewood tree.
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Jacob Margolis
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The desert willow was thriving at the test plot.
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The Honey Mesquite, also native to the southwest, was covered in bright yellow flowers and teaming with so many bees that the whole tree appeared to vibrate.
The honey mesquite can be invasive in some environments.
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The ghost gum, a type of eucalyptus from Australia was also well established. However, because of their oil content eucalyptus tend to burn violently in wildfires. Maybe not the best choice for fire prone locations. And the tecate cypress is native to the region and looks like it could be trimmed into a hedge. It's struggled a bit at the plot.
The ghost gum is a type of eucalyptus from Australia.
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The Tecate Cypress is native to Southern California and could work well in a hedge.
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Then there were the ones that appeared to need more maintenance, like the Palo Verde, which I see planted in drought tolerant landscapes across the area. It can thrive in hot conditions, and with a bit of pruning it might’ve looked better. Problem is it didn’t provide much shade.
And, to me, the Texas Live Oak looked to be an outright failure, as they were close to dead. It's reportedly done better in cooler conditions at the team's other test site in Irvine.
A desert museum Palo Verde
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Jacob Margolis
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A live oak
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Go see the trees yourself
Each tree in the private research plot has a counterpart located in parks across the region, in an effort to help determine how they do when they’re not babied.
“If you were looking at reference versus park sites, the reference sites are doing better as far as survivorship and growth. In the park sites there just is a lot of variability,” said van Doorn.
A first-grade student looks at a phonetic alphabet at Peralta Elementary in Riverside, on Nov. 19, 2025.
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Kyle Grillot
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CalMatters
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Topline:
A San Diego school board leader and veteran state lawmakers are running for California state superintendent. Two of them will advance to the November election.
Why now: A quiet primary race for state superintendent of public instruction is winding down Tuesday, with no clear front-runner emerging from a wide field of well-qualified candidates for California’s top schools job.
Why it matters: Ten candidates — including several legislative veterans — are vying for the opportunity to oversee the state’s 10,000 public K-12 schools during a tumultuous time. Schools are grappling with AI in the classroom, budget uncertainty, declining enrollment, lackluster test scores and other challenges.
Read on... for more on the race for state superintendent of public instruction.
A quiet primary race for state superintendent of public instruction is winding down Tuesday, with no clear front-runner emerging from a wide field of well-qualified candidates for California’s top schools job.
Ten candidates — including several legislative veterans — are vying for the opportunity to oversee the state’s 10,000 public K-12 schools during a tumultuous time. Schools are grappling with AI in the classroom, budget uncertainty, declining enrollment, lackluster test scores and other challenges.
The job itself is also up in the air. Gov. Gavin Newsom in January proposed an overhaul of California’s school governance structure, with far fewer duties for the superintendent. Instead, the State Board of Education, an 11-member body appointed by the governor, and a newly appointed education commissioner would hold most of the decision-making power. The superintendent would act as more of a policy advocate.
The shift would streamline a cumbersome and often opaque bureaucracy, adding transparency and accountability, Newsom said. It would also align California with most other states. Candidates for the superintendent position blasted the proposal, saying it takes away power from voters and concentrates too much control with the governor’s office.
Newsom and the current superintendent, Tony Thurmond, are both termed out this year.
Charter schools are no longer a divisive issue
The race for superintendent — at times, in previous election cycles, one of the most expensive and contentious races on the ballot — has been unusually quiet this year. In the most recent poll, conducted in April, no candidate garnered more than 10% of voters’ support, and 32% of voters were undecided. As of last week, no candidate had raised more than a few hundred thousand dollars. That’s in contrast to the 2018 superintendent race between Thurmond and Marshall Tuck, a former charter school executive, which generated more than $50 million in donations.
But there have been a few surprises in the race. The California Teachers Association and its historic nemesis, the California Charter Schools Association, endorsed the same candidate: Richard Barrera, a San Diego Unified school board member who was little known outside San Diego until this year. Both groups cited his accomplishments on the school board and his commitment to public education.
The dual endorsement shows how much has changed in education debates. For the past two decades, charter schools have been the No. 1 division in the superintendent’s race, generating millions in campaign donations from both sides. This year the subject has barely been mentioned, probably because charter school enrollment appears to have plateaued and both types of schools are now dealing with the same issues.
Another surprise has been the popularity of Sonja Shaw, president of the Chino Valley Unified school board. Shaw made headlines in 2023 when she took on Thurmond over the privacy rights of transgender students, and has made anti-LGBTQ policies the focus of her campaign. In the April poll, she was tied with Barrera.
Other top candidates include: Assemblymember Al Muratsuchi, former head of the Assembly education committee; Josh Newman, former head of the Senate education committee; Anthony Rendon, former speaker of the Assembly and a longtime early education program administrator; Nichelle Henderson, a Los Angeles Community College District board member, and Ainye Long, a teacher in San Francisco Unified.
Fire crews battle the Eaton Fire as it impacts a structure in Altadena on Jan. 9, 2025.
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Eric Thayer
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AP Photo
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Topline:
Have you lost your insurance or seen your premiums rise? The commissioner regulates the nation’s biggest insurance market and faces a complex set of issues as wildfire risk grows.
Why now: Californians finish voting Tuesday for who they think can best tackle one of the toughest jobs in the state: insurance commissioner. The commissioner is responsible for regulating the nation’s largest property insurance market that includes home and auto, plus health, pet, ride-hailing and life insurance, as well as workers’ compensation.
Why it matters: But the hot topic in the past few years as wildfire risk has increased has been home and fire insurance. The next commissioner will face many challenges that include trying to balance property insurance availability with affordability. Some insurance companies that had stopped renewing policies or writing new ones in the past few years are now taking advantage of new regulations that allow them to use new tools in setting their rates. This generally means premiums will rise as the Insurance Department, headed by the commissioner, is likely to keep approving increases in homeowners’ insurance premiums.
Read on... for more on the insurance commissioner race.
Californians finish voting Tuesday for who they think can best tackle one of the toughest jobs in the state: insurance commissioner.
The commissioner is responsible for regulating the nation’s largest property insurance market that includes home and auto, plus health, pet, ride-hailing and life insurance, as well as workers’ compensation.
But the hot topic in the past few years as wildfire risk has increased has been home and fire insurance. The next commissioner will face many challenges that include trying to balance property insurance availability with affordability. Some insurance companies that had stopped renewing policies or writing new ones in the past few years are now taking advantage of new regulations that allow them to use new tools in setting their rates. This generally means premiums will rise as the Insurance Department, headed by the commissioner, is likely to keep approving increases in homeowners’ insurance premiums.
The new commissioner will also have to deal with the aftermath of last year’s Los Angeles County fires. Insurance-claim delays and denials are a key part of the slow pace of rebuilding and recovery. State Farm, California’s largest individual insurer, and the FAIR Plan, the state-mandated fire insurance provider of last resort, are both facing lawsuits from homeowners and legal action from the insurance department over their handling of claims from those fires.
The leading Democratic candidates are state Sen. Ben Allen, who will be termed out of the Legislature; Jane Kim, head of the California Working Families Party who served on the San Francisco Board of Supervisors; Patrick Wolff, a financial analyst who has never held public office; and Steven Bradford, the former state senator and assemblymember. Neither of the leading Republican candidates has held statewide public office, either: Stacy Korsgaden, a longtime insurance agent, and Merritt Farren, an attorney who lost his home in the Palisades fire last year.
The candidates CalMatters interviewed mostly agreed on the problems that need to be tackled but proposed different solutions. A few of them have called for increased financial involvement by the state: Kim wants to establish a state authority for wildfires and floods funded by a portion of policyholders’ premiums. Farren wants to create a state reinsurance authority funded by a fee insurers charge their policyholders, something both Kim and Allen have expressed interest in. Bradford said he would study a public-private partnership to help keep insurers writing policies in California.
Consumer advocacy groups and former insurance commissioners say the job is complicated and involves a “brutal balancing act” that takes into account the needs of homeowners, business owners, landlords and renters while keeping insurance companies confident that the rates they’re charging match the growing risk of wildfires in the state.
U.S. Rep. John Garamendi, the Democratic congressman whose district includes much of Contra Costa and Solano counties, was the state’s first insurance commissioner and held the position two different times. He told CalMatters that the commissioner job is “complex, hard, detailed work.”
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The governor's podium at the Capitol Annex Swing Space in Sacramento on May 14, 2026.
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Miguel Gutierrez Jr.
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CalMatters
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Topline:
Xavier Becerra, Tom Steyer and Steve Hilton led in polls in the final days of the California governor election. Results are expected to begin coming in tonight.
Why now: California voters will advance two candidates for governor to the November election in the most unsettled gubernatorial race in recent memory, concluding a long and winding primary campaign in which Democrats struggled to pick a new leader for the nation’s most populous blue state.
Why it matters: The decision comes at a particularly consequential time for California. Residents face a crushing cost of living, nation-topping gas prices made worse by the war in Iran, wildfire risks that have driven insurance companies out of state, an unstable state budget, impending federal cuts to the state’s expansive health system and an economy dampened by immigration enforcement.
Read on... for more on governor's race.
California voters will advance two candidates for governor to the November election in the most unsettled gubernatorial race in recent memory, concluding a long and winding primary campaign in which Democrats struggled to pick a new leader for the nation’s most populous blue state.
The decision comes at a particularly consequential time for California. Residents face a crushing cost of living, nation-topping gas prices made worse by the war in Iran, wildfire risks that have driven insurance companies out of state, an unstable state budget, impending federal cuts to the state’s expansive health system and an economy dampened by immigration enforcement.
About the live results
We'll get our first results shortly after the polls close at 8 p.m. tonight.
In L.A. County, the first batch of results released includes vote by mail ballots received before June 2, followed by early votes cast at vote centers before the primary election day, then votes cast in-person on Election Day.
Democratic former state Attorney General Xavier Becerra, who has promised to fight Trump and freeze insurance and utility rates, is the leading Democrat in opinion polls and is favored by much of the state’s Democratic establishment. He appeared in contention to secure one of the top two spots for November heading into Election Day.
Republican Steve Hilton, a Donald Trump-endorsed former Fox News host who has vowed to cut income taxes and slash environmental regulations, was polling in second place ahead of Election Day, having consolidated support from many of the state’s conservatives.
But billionaire climate activist Tom Steyer, a progressive Democrat who has self-funded his campaign to the tune of $213 million, was still fighting for one of the top spots. A series of polls released in the final days of the race showed Becerra in the lead with roughly a quarter of likely voters’ support, and Steyer and Hilton locked in a tight battle for second.
Votes could take days or weeks to tally. Pollsters and strategists noted that lingering Democratic uncertainty led some voters to wait so they could back whoever appears to be ahead.
“Those polls could become self-fulfilling,” said Paul Mitchell, a Democratic strategist whose company tracks ballot return data.
The race to succeed Gov. Gavin Newsom, who will leave office at the end of the year due to term limits, is the marquee contest on the ballot Tuesday. The seat is considered a shoo-in in November for Democrats, who have nearly twice as many registered voters as Republicans, and holds national importance for the Democratic Party’s pushback to the Trump administration.
It’s also been one of the most unusually open races in recent state history.
No Democratic stars in the race
In contrast to decades of California politics dominated by movie stars, family dynasties and larger-than-life personalities, none of the most recognizable Democratic names jumped into the race.
That led to a crowded field on the left, briefly causing liberals to panic that Hilton and a fellow Republican, the bombastic Riverside County Sheriff Chad Bianco, could each garner more votes than any Democrat, locking the party out of the general election. The state Democratic Party began a public pressure campaign asking lower-polling candidates to drop out. Nearly all stayed in the race.
But when Democratic then-Rep. Eric Swalwell dropped out over multiple sexual assault allegations, Becerra was the clear beneficiary, raking in many of Swalwell’s donors and supporters. He’s been surging ever since, successfully dodging criticism of his record. Steyer, who spent $200 million boosting his name recognition through campaign ads, consolidated much of the party’s left flank. Former Rep. Katie Porter, a progressive dogged by allegations about her temperament, fell behind. San Jose Mayor Matt Mahan, a moderate backed by Silicon Valley billionaires, rose from single digits in the polls, but not enough.
Trump’s endorsement of Hilton quickly helped him pull away from Bianco, making it unlikely both Republicans would come in first and second. If Hilton advances to the November election, he faces long odds of being elected against a Democrat.
Both he and Steyer have spent the final weeks of the campaign portraying Becerra as a symbol of the status quo and themselves as agents of systemic change amid multiple state crises, with affordability dominating the race.
For Hilton, that would mean ending 16 years of “one-party rule” under Democrats, slashing spending and reversing many liberal policies such as greenhouse gas reduction mandates, the progressive tax system and parts of the social safety net.
“After 16 years of everything being in one direction, that’s left a lot of people dissatisfied,” he said last week. “Anybody who wants change or balance in our politics, the only choice is for me.”
His name recognition as a former Fox host helped him start the race with a fan base. Nancy LeVesque, a retired salesperson from Roseville, already admired him and said he was an easy choice as she dropped off her ballot at a Placer County vote center on Monday. She liked that he would bring an outsider’s perspective to the governor’s office and a change for those leaving California because of its liberal politics.
“We have lost so many good people,” to other states, she said.
Steyer styled himself as a populist “class traitor” who would force lower costs for Californians by taking on monied special interests like investor-owned utilities, the real estate industry and health insurance corporations. He made a litany of progressive promises on climate change, single-payer health care and raising taxes on the wealthy.
Undecided voter Tina Varnado attended a rally last week for Steyer hosted by her union, which represents home health aides. The South Sacramento resident is a full-time caretaker for her elderly mother and her adult daughter who had open-heart surgery. Between her mother’s social security checks and her pay as her daughter’s health aide, “we do have to spend everything we have every single month” to stay afloat, she said.
“Everything he touched on really touched home for me,” she said after hearing Steyer speak. “If we can lower prices, maybe we can start putting money down on a home for my future.”
Becerra has emphasized his long experience in government, including his lawsuits against the first Trump administration and his time as U.S. Health and Human Services secretary during the pandemic.
That appealed to Evan Cragin, of the California Young Democrats, which endorsed Becerra weeks before his sudden surge. Cragin said he wants the next governor to have government experience to push back on federal “abuses” from the Trump administration.
“Secretary Becerra has done that before,” Cragin said.
Surrounded by supporters at the offices of Planned Parenthood Affiliates of California on Monday, Becerra dismissed his opponents’ promises, pointing to past accomplishments including passing the Affordable Care Act and defending the Deferred Action for Childhood Arrivals immigration program.
“You can have all these great inflated promises,” he said. “Getting things done is not easy.”
Most areas will see temperatures in the mid 70s to mid 80s.
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Courtesy Angeleno Wine Company
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Courtesy Angeleno Wine Company
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QUICK FACTS
Today’s weather: Morning clouds then partly cloudy
Beaches: 66 to 71 degrees
Mountains: mid 70s to mid 80s
Inland: 80 to 89
Warnings and advisories: None today
What to expect: Overcast skies for areas along and close to the coast. Otherwise, expect a partly cloudy afternoon with highs ranging in the mid 70s to mid 80s for most of SoCal.
Read on ... to learn more.
QUICK FACTS
Today’s weather: Morning clouds then partly cloudy
Beaches: 66 to 71 degrees
Mountains: mid 70s to mid 80s
Inland: 80 to 89
Warnings and advisories: None today
May gray has come and gone, and now it's time for June gloom.
Overcast skies will be present this morning, especially along the beaches and valleys closest to the coast. Otherwise, we're in for a partly cloudy afternoon.
Today's temperatures at L.A. County beaches will stay around 66 to 71 degrees, and reach 76 to 80 degrees for places more inland.
In Orange County, expect similar temperatures with highs from 67 to 74 degrees for Huntington Beach and surrounding areas. More inland areas like Anaheim and Garden Grove will see temperatures of up to 79 degrees.
Moving on to L.A. County valleys, expect high temperatures in the low to mid 80s.
In the Inland Empire, temperatures will range 80 to 89 degrees.
