The Brief

Here's an unassailable fact: Trees are awesome. Among the laundry list of benefits, they provide shade in our increasingly warming weather, they clean the air, prevent soil erosion, reduce noise pollution.

Which is why a rise here in Southern California of a practice known as "topping" is worrying arborists and others. You've probably noticed it: Trees having their canopies and branches cut off. The result (see photo above) is dramatic.

"This is sadly a very common practice.... I should say malpractice, honestly," said Bryan Vejar, a senior arborist at the environmental organization TreePeople. "Once you notice it and start to understand the hazards and harms of 'topping,' you'll see it everywhere."

Rachel Malarich, L.A.'s forest officer, said topping has indeed become more pervasive.

"I have seen the proliferation of tree topping across our region over the past decade or so," she said. "When I see trees that are cut that way, it is a little gut wrenching."

Why less is more when it comes to trimming

The practice of topping is hard to kick partly because of simple economy, said Vejar, explaining that people paying for tree trimming equate value with volume.

"So if I took out 90 or 100% of the volume out of the tree, you would think, 'Oh wow, what a good value I got," he said.

He added that people also mistakenly think that the more you chop off, the longer it'll take for it to grow back. In reality, he said "less is more with trees," meaning taking more care with what is trimmed can prolong the life and health of a tree, and make rapid growth less likely. That's because a lot of pruning can lead to what he calls "sort of a vicious cycle of regrowth."

Why topping = rapid regrowth

The rapid regrowth happens because topping triggers a panic response and sends the tree into overdrive.

"When you top a tree, the physiological response from the tree is to produce a lot of what are called water sprouts," Vejar said.

Those are all the long, thin branches that shoot out from a tree around its stumps.

"When you remove its photosynthetic array, all of its leaves and canopy, you're robbing the tree of its ability to feed itself," Vejar said. "It needs to put out some growth in order to shade the tree and also produce enough photosynthesis to keep the system running."

(

Fiona Ng

/

LAist

)

These branches are weaker and more at risk of breaking and falling. Big cuts also make trees prone to pest and diseases.

A topped tree with water sprouts.

(

Fiona Ng

/

LAist

)

"That big surface area of the cut is basically a Petri dish for disease. And if there's any exposed heartwood, that is the central wood in the middle of the wood, then that is a prime real estate for wood decay organisms to start infesting the tree and killing the tree," he said.

Malarich, who manages the city of L.A.'s urban forest, said topping also makes it difficult to cool the city down.

"It really makes it hard for us to meet our canopy goals as a city, because when we're trimming trees this way, it reduces the shade provided by those trees," she said.

Malarich added that city crews, which service trees in public parks and those planted between curbs and sidewalks, don't engage in topping. But she said with 80% to 90% of the city's overall canopy on private property, Angelenos have an important part to play in preserving these natural covers.

"The goal should be to take as little as possible off the tree," she said.

When topping makes sense

There are circumstances where topping a tree could make sense, Vejar said, like if there's a fast-growing tree under the power line. Or, if a tree is dying.

"You want to retain this tree for as long as possible, but you also want to make sure that the limbs that do fail don't fall on your house or on your car or on your property," he said.

All is not lost, even if you have topped a tree. With time, patience and the help of an arborist in a process called "restorative pruning," the stronger new branches are nurtured to help the tree regain its health.

"It takes years to build a house and only a few moments of carelessness to burn it down, right? Well, it's sort of the same with trees," Vejar said.

Pro-tips on tree maintenance

• Think through where you are going to plant a tree. "You don't want to, you know, put a tall, fast growing tree underneath the power line because eventually it's going to become in conflict and you're going to have to top it," Vejar said.
• Find an arborist certified by either Tree Care Industry Association or the International Society of Arboriculture to help you with tree maintenance, Vejar said. The latter has an online directory of certified arborists local to your area. Malarich said to also ask whether they follow the ANSI A300 standards for tree care.
• Try to trim back a tree during cooler months. "It's very stressful for the tree to be trimmed in the summer," Malarich said.
• Get multiple bids.
• Talk to your arborist and ask questions before deciding. "They should be able to tell you why they're removing certain portions of the tree," Malarich said.

After all, the better we treat these majestic organisms, the better they will treat us. "They're good for us mentally, psychologically and socially," said Vejar, who urges everyone to be realistic when making decisions about trees.

Everybody, he said, wants a big tree that grows fast, but also one that's low maintenance, drought tolerant, disease resistant and with no invasive roots — all while holding its shape over time.

"Those don't exist," he said.

This story was originally published by CalMatters. Sign up for their newsletters.

In 2019, first-year Gov. Gavin Newsom inherited a state flush with cash. With a $21.4 billion budget surplus to play with, an ambitious Newsom invested billions in affordable housing, child care and healthcare expansion while paying down the state’s debt and shoring up reserves.

The next governor won’t be that lucky.

When Newsom unveils his last spending plan as governor Friday, he will do so with the specter of a projected $18 billion deficit — the result of the state’s fast-growing spending, federal funding losses and heightened economic uncertainties under President Donald Trump’s administration.

The deficit could balloon to $35 billion annually in the next few years if state leaders don’t pursue long-term solutions, namely making sustainable revenue increases or cutting spending, according to the Legislative Analyst’s Office, the nonpartisan fiscal adviser to lawmakers.

But neither will be appealing options to Newsom and legislative leaders this year.

They have repeatedly resisted increasing taxes on average Californians and high-income earners alike — a politically dicey pitch to make in a state with high tax rates and increasing revenue. Spending cuts are equally painful to swallow, especially for Democrats running for re-election in November who have fought to expand services, such as Medi-Cal, that may now be rolled back.

For Newsom, a lame-duck governor with presidential aspirations, there is even less incentive to address the state’s long-term budget health through major policy changes, political strategists say.

“It’s not an uncommon occurrence in California for a departing governor to leave a note on the new governor’s desk that they’ve got a budget deficit,” said longtime Democratic consultant Garry South.

But how Newsom tackles the structural deficit will almost certainly have implications for his expected presidential bid. State Republicans, such as Assemblymember David Tangipa of Fresno, are already blaming the budget problem on Newsom’s mismanagement. “A Newsom presidency would be a fiscal and governance disaster of historic proportions,” Tangipa wrote in a December op-ed.

It’s the fourth consecutive year in Newsom’s tenure that the state is projecting a deficit even as revenue grows. In the past, state Democratic leaders resorted to temporary fixes such as internal borrowing, deferring payments, one-time cuts and drawing from California’s rainy day fund to avoid cutting into the social safety net.

But that cushion is deflating: The state’s reserve stands at $14 billion, half its peak balance, after two years of withdrawals. State leaders have borrowed more than $20 billion from other state funds, debts that will come due in later years. Continuing to rely on those options would leave the state “undeniably less prepared” for an economic downturn, the LAO warned.

“Eventually you are going to run out of Band-aids,” said Steve Maviglio, a Democratic strategist who worked for then-Gov. Gray Davis during a massive budget deficit. Newsom "has used every trick in the book, and after a certain point, there’s nothing left.”

More healthcare cuts to come?

Newsom has not indicated whether he’ll consider cuts to Medi-Cal, the state’s primary health insurance program for low-income residents. But as the state’s most expensive program, it is an attractive target. More than half of the $200 billion program’s funding comes from the federal government.

Last year, as Newsom and legislators scrambled to close a $12 billion budget gap, they froze new Medi-Cal enrollment for undocumented immigrants, charged immigrant enrollees a $30 monthly premium and delayed cutting certain benefits. The cost of Medi-Cal has been rising faster than expected, forcing the state Legislature to allocate $6.2 billion midyear to prevent a shortfall.

The decision was contentious, with some healthcare advocates and Democratic lawmakers slamming their leaders for creating a “two-tiered healthcare system” that deemed immigrants less worthy of quality coverage.

“That was an incredibly disappointing backslide,” said Amanda McAllister-Wallner, executive director of Health Access California, which advocates for universal healthcare.

This year, Trump’s budget reduced the federal government’s share of funding to Medi-Cal, requiring the state to pay more to provide the same benefits. California is projected to spend at least $1.3 billion more to implement that change, a figure that could reach $5 billion by fiscal year 2029-30, the LAO estimated.

The Martin Luther King Community Hospital in Los Angeles.

(

Pablo Unzueta

/

CalMatters

)

Assemblymember Mia Bonta, an Oakland Democrat who chairs the Assembly Health Committee, said solving the state’s budget crunch shouldn’t come at the expense of health care.

“California needs its state and federal leaders to look for more innovative solutions to fill the gaps, make healthcare affordable, and keep our families healthy,” she said in a statement that did not offer specific alternatives.

Any cuts to Medi-Cal could bring political consequences for Democrats who often pride themselves on expanding social services. Rolling back Medi-Cal could hurt Newsom’s legacy, too, since it was under him that the state began offering Medi-Cal to immigrants.

“Democrats are the party of expanding healthcare,” Maviglio said. “To slash it goes against everything they stand for.”

McAllister-Wallner acknowledged she isn’t optimistic about the budget outlook. But she said she hopes the state finds new revenue through taxing corporations instead of making cuts to vulnerable populations.

If “we are addressing this through cuts only, and cuts to the most vulnerable, that’s … not the leadership that we are looking for,” she said.

State leaders could also walk back some of last year’s funding commitments in other areas. While state lawmakers negotiated $500 million for homelessness to counties and delayed it until next year, it is not guaranteed. Newsom, who has blamed the state’s homelessness problem on local governments, could withhold the money.

Newsom also promised last year he’d reach a deal with Bay Area transit advocates over state funding. But last month, in light of the budget shortfall, Newsom urged advocates to dip into previously allocated dollars to save the regional transit network, instead of a $750 million loan the advocates had requested.

Taxing the rich a nonstarter for Newsom

It’ll be hard to muster the political will in Sacramento to raise taxes.

Former Assembly Speaker Anthony Rendon, a Los Angeles Democrat running for state superintendent of public instruction, said he’s long supported higher taxes on industries that have “skated away from taxation for a long time.”

But even the most progressive Democrats in California have had little appetite to raise taxes, he said, because many represent affluent areas such as Silicon Valley where their wealthy donors live.

Even when the state faced a projected $56 billion deficit over two years in 2023, Rendon said Democrats were “shrugging” at the problem and pointing to the state’s reserves as a solution, which he said reflected a culture of reliance on the rainy day fund.

This year, Newsom has already spoken out against a proposed labor-backed wealth tax ballot measure, consistent with his past opposition to similar proposals.

The ballot measure, titled “The 2026 Billionaire Tax Act” and filed with the state attorney general’s office in October, seeks to tack a one-time 5% tax on those with a net worth of at least $1 billion and use the money to fund the state’s healthcare and education programs. The effort is led by the SEIU-UHW, a powerful labor union representing healthcare workers, and St. John’s Community Health, one of the largest nonprofit healthcare providers in Los Angeles County.

State. Sen. Roger Niello, a Roseville Republican and vice chair of the Senate Budget Committee, applauded Newsom’s opposition to the proposed tax increase.

“To have a situation where we have developed an increasing deficit in the face of an economy that is not in recession, and revenues are increasing, it would seem to be silly to solve that by further increasing revenue,” he said.

While taxing the rich is a popular Democratic talking point, backing a proposal like that could mean alienating the wealthy donors Newsom will likely rely on for his presidential run.

There would also be no political gain for Newsom in his last year to stabilize the state’s progressive tax structure, which heavily relies on high-income earners, despite him promising to do so when he took office.

“He’s going to make more enemies doing it than he would not doing it,” Maviglio said.

This article was originally published on CalMatters and was republished under the Creative Commons Attribution-NonCommercial-NoDerivatives license.

This story was originally published by CalMatters. Sign up for their newsletters.

After just over two months, Southern California Edison has drawn more than 1,800 customers to a compensation program meant to settle scores of lawsuits against the company over the deadly Eaton Fire. As of Monday, the company has made offers to 82 of those who applied, Pedro Pizarro, chief executive of Edison’s parent company Edison International, told CalMatters.

Fire survivors, who have been providing feedback to Edison since before it launched the settlement program still have strong criticisms of the utility’s compensation effort, called the “Wildfire Recovery Compensation Program.” They complain that it requires participants to forego lawsuits against the company and blocks them from seeking further compensation for fire-related health claims. Many said the program’s payment caps, which limit the amount claimants can receive, were too low and enable Edison to pay less than the utility might otherwise owe should it be found responsible for the fire.

The Eaton Fire burned 14,000 acres of Los Angeles County in January and killed 19 people. While the official cause has not yet been determined, a leading theory is that Edison’s equipment sparked the blaze. The U.S. Department of Justice is among those who have blamed the utility for the fire.

Insurance money and personal savings are running out for people who lost homes, livelihoods and loved ones in the fire, they and their advocates say. Many are unhoused or facing housing insecurity. One survey estimated 80% of Altadena residents were still displaced by the fire as of October. The Eaton Fire Survivors Network, a prominent grassroots organization, called on Edison to provide up to $200,000 per displaced household “based on verified costs” to help cover housing costs.

“It’s Edison’s responsibility to solve all of this,” Joy Chen, executive director of the group, said. “It’s their fire."

About $7.6 billion in insurance claims related to the Eaton Fire were paid out as of November, according to the California Department of Insurance, the most recent figures available. About 90% of the payout was for residential property.

Edison offered a collective total of $34.4 million to settle the 82 claims, and none of the offers were declined, it said.

About half of the claims that received an offer from Edison as of December, Pizarro said, were for total losses, and about half were related to smoke and ash damage. While he did not provide specific numbers, Pizarro said that the claims were spread across geography, income levels and home values. Many of those that have been made offers are part of the program’s fast-track option.

At a Dec. 16 press conference held by the survivors network, displaced residents spoke about how unstable housing and the loss of their homes has affected their lives. Gabriel Gonzalez, a plumbing company owner, lost his home, business and about $80,000 worth of tools in the fire. He lived out of his car for an extended period before receiving a small amount of financial assistance that helped him stay in a rental for a few months. But that money is expected to run out this month.

“As of the first of January, I’ll probably be back in my car,” he said at the event.

Pizarro told CalMatters that Edison will not be providing money to residents for housing outside of its compensation program, citing the need to validate expenses. The survivors network request for housing cost assistance was limited to verifiable costs.

One criticism of the program was that children do not receive the same compensation as adults. Under the current version of the program, children receive between 50% and 65% of the compensation adults receive for a loss of their residency, depending on the damage category. If their primary home that they live in was destroyed, adults would get $115,000 and children would receive $75,000. These rates are slightly higher than a draft version of the plan Edison released in the fall.

An open letter at the time from the Eaton Fire Survivor’s Network said giving children less than an equal valuation to adults “treats their suffering as lesser when it is, in reality, greater.”

Pizarro said Edison went with a lower valuation because children often don’t receive as much as adults do under similar programs and adults “end up bearing more responsibility and more cost” for the household and “arrangements for the children.”

“The reality is that adults carry much more burden here,” he said, “and so it’s fair that they, you know, that we have more compensation targeted at the adults.”

Another frustration those affected by the fire expressed was the requirement that participants waive their right to sue the company. Legal representatives of fire survivors who are suing the company cautioned that the settlement program through Edison could short people of any damages and suffering compensation a court might award, as well as potential long term health care compensation or monitoring.

“We are approaching this as a way to settle litigation,” Pizarro said. “It is a form of legal settlement, and legal settlements are typically settlements of all matters, otherwise they’re not really, you know, they’re not really a conclusion to litigation.”

This article was originally published on CalMatters and was republished under the Creative Commons Attribution-NonCommercial-NoDerivatives license.

The U.S. Department of Health and Human Services announced Monday that it would rescind a series of Biden-era rules governing one of the largest federal funding sources for child care. The move comes less than a week after HHS confirmed it was freezing all federal funding through that same program.

The Child Care and Development Fund (CCDF) sends money to states, tribes and territories to help make child care more affordable for low-income families.

The Biden administration's rules encouraged states to base payments to child care providers on enrollment rather than verified attendance, pay providers in advance of services and favor guaranteed slots with providers over vouchers.

Now, HHS says it plans to restore attendance-based billing, it will no longer require that providers be paid in advance and it will reprioritize vouchers.

"When controls are not in place, bad actors can bill for children who aren't there," said Alex Adams, assistant secretary for family support at HHS's Administration for Children and Families. "Families and taxpayers deserve proof that services are being delivered to children."

But child care advocates told NPR that states already have many controls in place to prevent fraud.

"What we know to be true is that there are longstanding program integrity requirements that have been in place and are regularly updated, annually updated," said Susan Gale Perry, CEO of Child Care Aware of America, which helps families access affordable child care across the country.

Approximately 1.4 million children and 857,700 families per month received child care assistance through CCDF in 2019, according to the latest data posted on the HHS website.

Melissa Boteach, chief policy officer at Zero to Three, a nonprofit that advocates for infants, toddlers and families, said the proposed policy changes introduce "chaos and confusion" by rolling back provisions that aimed to make the child care industry more stable and affordable.

This follows a funding freeze announced over the holidays

Monday's announcement comes days after HHS said it was freezing the federal funding provided through CCDF.

HHS spokesperson Andrew Nixon told NPR on Wednesday that the agency was freezing CCDF funds effective immediately, and said the agency would unfreeze funding after individual states provided certain "administrative data."

"It's still unclear to many states who have to administer these programs what exactly this means." Boteach said. "And that lack of clarity has real consequences for families and for early educators."

She also said there has "not been clarity provided on whether or not funding is forthcoming, on what needs to be done for it to turn back on and what states are supposed to do in the meantime."

HHS has not yet responded to NPR's request for clarity on how Monday's announcement relates to the funding freeze.

"What we do know is that child care providers operate on [a] very thin … margin of profit," said Perry of Child Care Aware of America.

She said going "even a month" without funding could result in child care centers closing – which would impact both children who benefit from CCDF funding and those who do not.

A focus on child care providers in Minnesota

The recent focus on federal child care funding comes in response to allegations of fraud by Minnesota day care providers.

As NPR has reported, the day after Christmas, Nick Shirley, a right-wing social media influencer, posted a video in which he claimed to show Somali-American-run day care centers cheating the federal government out of millions of dollars. The video doesn't offer clear proof, but it went viral.

On Dec. 30, HHS Deputy Secretary Jim O'Neill posted on X about "the serious allegations that the state of Minnesota has funneled millions of taxpayer dollars to fraudulent daycares across Minnesota over the past decade." He announced actions "against the blatant fraud that appears to be rampant in Minnesota and across the country," including requiring "a justification and a receipt or photo evidence before we send money to a state."

In Monday's HHS announcement, O'Neill said, "The reforms we are enacting will make fraud harder to perpetrate."

According to HHS, the rule changes are subject to a 30-day public comment period.

Copyright 2026 NPR

A typical single-family house is encircled by green, its shrubs and plants sitting just under windows and hugging exterior walls. It's an image that California is trying to get homeowners to rethink as the state's risk of extreme wildfires grows.

One year after the fast-moving Eaton and Palisades Fires destroyed more than 16,000 structures in the L.A. area, California is drafting the toughest statewide rules in the country for vegetation. In areas at risk of wildfires, homeowners would be required to clear some or all of the plants within 5 feet of their house, depending on what regulators decide. Well-maintained trees would still be allowed.

The idea, called Zone Zero, is to prevent plants and flammable items from igniting during a wildfire, spreading flames to the house and the surrounding neighborhood. In high winds, most homes burn down due to embers, the tiny bits of burning debris carried by the wind.

Still, the pushback has been strong, even in the Los Angeles area neighborhoods where so many lost homes. In public meetings, homeowners have voiced concerns about losing greenery and shade, as well as the cost of clearing the vegetation. Some say they believe plants and hedges saved their homes by acting as a buffer, though many scientific studies show that vegetation increases the risk a building will burn.

The new defensible space rules will affect about 17% of buildings in California. But they could set a much bigger precedent across the West, as more states deal with wildfires growing increasingly destructive as the climate gets hotter.

High winds spread burning embers into Altadena during the Eaton Fire, leading to the fire's rapid spread through neighborhoods.

(

Ryan Kellman

/

NPR

)

"How we step up and do this is hard, but I think we have to adapt and change a bit if we're going to try to not keep losing our homes," says Michael Gollner, who runs the Berkeley Fire Research Lab at UC Berkeley.

Hundreds of tiny fires

When the Eaton Fire broke out the evening of Jan. 7, Richard Snyder was at his home in Pasadena, working on a slide presentation about wildfire risk. Snyder had spent more than 30 years in firefighting before retiring and now does wildfire risk consulting. So when he saw the smoke in the nearby foothills, driven by powerful winds, he knew it didn't look good.

"I know where the smoke is going is going to be where the fire is going, and I saw this smoke heading off into Pasadena," Snyder says.

He told his wife to evacuate and started telling neighbors to be ready. Snyder decided to stay. Although the fire itself was still more than a mile away, he knew the biggest danger was the glowing embers being blown into his neighborhood by the wind.
"And then it happened," he recalls. "There was a palm tree that lit off and showered our neighborhood with embers and it started a fence on fire at my neighbor's house. Myself and two other retired firefighters tried to put that fire out with garden hoses, and it wouldn't work. It was too hot and the wind was too strong."

In windy conditions, embers can rapidly spread a fire, landing in dry leaves in a roof gutter, bark mulch on the ground or even being sucked into an attic through a vent. Once that fire gets going, the extreme heat and embers help it spread to neighboring buildings.

"I'm looking over and I'm seeing my St. Augustine grass burning," Snyder says. "Who would have thought that green St. Augustine grass would start burning? There's hundreds of little tiny fires burning in the yards and next to the houses of my neighbors."

Several homes in Snyder's neighborhood were lost. His own survived, but with damage. While he says it was a shock, it wasn't surprising to him. For years, wildfire experts had been finding that houses are vulnerable to wildfires both because of the building materials they're constructed with and when something flammable is next to the house. The concept of Zone Zero focuses on the crucial zone within five feet of a structure.

"We're not going to stop the fires, but we can absolutely keep them from burning our houses down," Snyder says. "But it's a change."

Public meetings get heated

California regulators are creating rules for the "ember-resistant zone" next to houses under state law. The original deadline was 2023, but the effort flagged. After the Los Angeles fires, Gov. Gavin Newsom set a new deadline for the end of 2025. With all the debate, regulators pushed past that deadline and say they expect to keep working through March to gather more feedback.

The proposed rules would prohibit flammable items such as firewood, bark mulch, dead leaves and weeds within five feet of a house. Fences and gates would need to be made of metal or other non-combustible materials in that zone. The rules wouldn't go into effect for existing homes for three years and local fire agencies would have some discretion over tailoring it for their areas.

The sticking point is over green vegetation. Trees would be allowed as long as they're well-maintained, by keeping branches five feet above the roofline, for example. When it comes to plants, regulators are considering several options: only allowing potted plants in Zone Zero, allowing plants under 18 inches, or allowing any well-maintained plants with no dead material.

Steve Hawks of the Insurance Institute for Business & Home Safety inspects a home after the Eaton Fire. Embers caught a pile of flammable material, but the house's fire-resistant siding prevented it from spreading.

(

Ryan Kellman

/

NPR

)

The change isn't being welcomed by some California residents. In September, California's Board of Forestry and Fire Protection held a public hearing in Pasadena to gather feedback on the proposed rules.

"Our community just endured the most destructive residential fire disasters in modern history, yet this board is pushing Zone Zero policies that completely miss the mark," Jessica Rogers of the Pacific Palisades Resident Association said at the hearing. "My home and my neighbors' homes burned because of adjacent structures, not vegetation."

In the hours of public testimony, some residents spoke in support of clearing Zone Zero to prepare for wildfires that will inevitably come again. Other residents pushed back, worried that houses on small lots would lose too much greenery and shade, reducing wildlife habitat. Some raised concerns about the cost, since the new rules wouldn't include funding for landscaping work, though California is developing other programs for that. A few residents noted that in the aftermath of the fires, some plants were still left standing.

"I saw the well-hydrated hedges that I had planted protecting my house, acting as a fire catcher, essentially, because they were upwind," Pacific Palisades resident Martin Hak testified at the hearing.

"We know that not everyone will agree with every decision or aspect of what comes next," Board of Forestry and Fire Protection executive officer Tony Andersen wrote about the Zone Zero rules. "But we do know that many Californians agree that protecting our communities is not a passing fad or a momentary response."

The board also posted its responses to many of the questions raised at the hearings.

Do green plants burn?

"We don't really know how often plants can be 'protective' and provide a buffer for homes," says Max Moritz, wildfire specialist with the University of California Cooperative Extension at UC Santa Barbara.

The destruction in a wildfire can be a patchwork, with some homes and plants left standing directly next to others burned to the ground. In the aftermath, it's difficult to know when vegetation was responsible for spreading fire because the evidence is often completely destroyed.

Ember-driven wildfires can leave a patchwork of destruction behind. In Altadena, some buildings and vegetation were left intact, while others were destroyed

(

Lauren Sommer

/

NPR

)

Moritz is one of the few fire experts who say that green plants may not pose a risk to houses and that more research needs to be done. Greener plants, which hold water in their leaves, are harder to ignite. He agrees that some plants, like highly flammable juniper and cypress, should not be allowed, nor should plants with dead leaves or dry branches.

"The really important aspect to the plants is the dead material," he says. "If most homeowners are just going to let dead material accumulate in Zone Zero anyway, then it makes sense that there shouldn't be any plants in Zone Zero."

Other wildfire experts warn that in the hot, windy conditions of an extreme wildfire, all vegetation poses a potential threat.

"Just because a plant is very moist doesn't mean it's non-flammable," says Gollner of UC Berkeley. "Having a well-watered plant is less of a risk, but it's not no risk."

What makes things burn

Gollner runs a "burn lab" on campus, where his team studies how and why materials burn. There, they place a well-watered shrub inside a special chamber lined with sensors. They ignite a small bit of mulch under the plant. After a few minutes, the flames creep up into the base of the plant.

"You can see, once the flames touch the leaves, they immediately dry out and burn," he says.

Gollner says in a wildfire, if a neighbor's fence or shed is on fire, it can dry out and ignite the vegetation next to a home. If those plants are within Zone Zero, the fire can then reach a neighboring house. Even shrubs and hedges that look healthy on the outside are often dry and bare in the interior. At a recent California Board of Forestry meeting, Gollner's colleagues presented their recent experiments about how green plants can burn.

Other scientific studies show that vegetation is influential in wildfire risk. A team from the Insurance Institute for Business and Home Safety, a non-profit research group funded by the insurance industry, inspected damage at more than 250 homes in the Los Angeles fires. They found when Zone Zero had vegetation in quarter or more of it, the chances that a home was damaged or destroyed were almost 90%.

Michael Gollner watches a burn test in his lab at UC Berkeley. Green plants take longer to ignite, but he says leaves can dry out quickly in hot, dry conditions during a wildfire.

(

Lauren Sommer

/

NPR

)

Gollner and colleagues also looked at several of California's recent wildfires and used computer models to simulate those burns under different conditions. Their study found Zone Zero rules could have reduced structure losses by 17%. Another study looking at the 2018 Camp Fire and the 2017 Thomas Fire found having mostly vegetation within six feet of the walls was a big factor in whether the building was lost. Other studies have also shown the importance of defensible space.

Still, minimizing vegetation alone won't guarantee that homes survive. Wildfire experts say buildings need to be fire-resistant as well, a crucial factor in reducing fire risk. Many older homes have wood roofs, wood siding or single-paned windows, which are much more vulnerable to burning. Gutters need to be clear of dead leaves and attic vents need to be covered in a fine mesh, so embers don't get inside.

Homes built after 2007 in wildfire zones are required to meet California's building codes for fire-resistant materials, but most of the state's housing stock is older than that. Some vulnerabilities can't be changed, like when houses are built close together on smaller lots.

With wildfires, neighborhoods are only as strong as their weakest link. Once a fire starts, it can spread from house to house, so wildfire preparation is far more effective when an entire community fortifies itself — something regulators have cited as a reason for the new vegetation rules.

"It's a change of aesthetic, and it's incredibly difficult because it's people's private property," Gollner says. "But a wildland fire is unique amongst all catastrophes in that what your neighbor does directly affects you. We know that whatever we do, it's got to be across the community."

Copyright 2026 NPR