The deadly fires that devastated homes in Pacific Palisades and Altadena also laid waste to a lush canopy of leaves and pine needles that had cooled and shaded residents here for generations.

Now, more than a year later, trees that had survived the flames are disappearing at a troubling rate.

Since the January 2025 fire siege, roughly 20% of surviving street trees have gone missing, according to preliminary results from a University of California research team.

Many of the hundreds of missing trees probably would have recovered from the damage they suffered in the fires, experts say.

The results from the survey of about 500 trees in the Palisades and 1,500 in Altadena — including conifers, palms, Chinese elms and carrotwoods — seem to confirm worrying patterns observed by arborists and local volunteers in the burn scars, who said losses will probably continue for years to come.

Several factors appear to be at work.

Even as the Palisades and Altadena rebuild, local governments only undertook limited efforts to water recovering trees. At the same time, building contractors have been quick to remove trees that stand in the way of construction, while debris removal crews have cut down living trees that they mistakenly identified as dead.

In response to the continuing loss of trees, a group of arborists and volunteers are working to keep the recovering trees alive — and hopefully someday start planting the next generation of the burn scars’ urban forests.

While many homeowners view trees through the lens of maintenance costs — regular pruning can be expensive, and tree roots can wreak havoc on sidewalks and underground pipes — the benefits of trees are numerous and well-documented, experts say.

The shade they provide and the process of evapotranspiration — where water on the surface of leaves evaporates and carries away heat similar to how human sweat works — can cool neighborhoods by more than 10 degrees. This cooling reduces the risk of heat illnesses and can lower homeowner energy costs.

Trees also improve air quality, improve residents’ mental health, and reduce the risks of flooding and landslides. Meanwhile, fire experts say that reasonably spread-out and well-maintained trees do not pose a significant fire risk.

Edith de Guzman, a climate change, water and urban forestry researcher with UCLA, has been studying the burn area trees with her team. The researchers did their first assessment in the months following the fire, and donned orange vests to do it again this past month.

Edith de Guzman uses a hypsometer to calculate the height of a tree in Pacific Palisades.

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Their discovery that roughly two out of every 10 trees the team went back to check on were missing was particularly concerning to De Guzman because her team was only looking at public street trees — which the city and county have authority over and work to protect — as opposed to trees on private property, which are maintained or felled largely at the discretion of the property owners.

“On private property it’s a different story — except for protected species,” she said. Public trees, however, “we are still seeing removals that are unnecessary, and the city is not sure who is responsible.”

L.A. City Bureau of Street Services did not respond to a request for comment.

The fires themselves killed and damaged a significant fraction of the areas’ urban tree cover — both private and public — although precise estimates are hard to come by.

Almost immediately, the surviving trees faced trouble.

David Card, board president of the Palisades Forestry Committee, said shortly after the fire, trees began to fall. In the chaos of the aftermath, it was unclear what organizations — or what agencies — were responsible.

Rebecca Latta, co-founder of Altadena Green, said that when the U.S. Army Corps of Engineers debris removal efforts began, leadership worked with them to save trees but that the Army Corps’ contractors often pressured homeowners to approve tree removals and incorrectly identified native oak trees — which did not have leaves at the time — as dead.

Chinese elm trees rise over Pacific Palisades.

Once private contractors arrived to begin rebuilding, they often removed trees on private properties they determined were in the way — and sometimes even removed public street trees they did not have authority over, the advocates said.

At the same time, neither the city of Los Angeles nor the county have routinely watered surviving public trees — which arborists say is essential to helping damaged trees recover. The county did one round of watering in Altadena, but found it to be too expensive, Latta said. The city conducted no watering in the Palisades due to a lack of resources, according to Card.

L.A. County Public Works said it remains “committed to preserving the community’s public trees.” It routinely waters newly planted trees and will continue to assess the needs of mature street trees, the department added.

So, local groups are stepping up to save the trees.

The Forestry Committee began sending two watering trucks around the Palisades: a 2,000-gallon tanker from a landscaping company and a 500-gallon tank on the back of a trailer. Altadena Green began conducting property tree surveys to help residents understand which damaged trees would probably survive and how to take care of them.

The Forestry Committee is also working on a long-term tree planting program for the Palisades that will utilize fire-resilient tree species — although the Los Angeles Department of Water and Power asked the Forestry Committee to hold off for a year as it starts working to move power lines underground, Card said. Excavation will probably occur on plots where street trees are typically placed.

Researchers Oliver Khachikian, Matthew Murphy, Mariana Vargas and Sophia Riemer prepare to survey trees near Aiglon Plaza in Pacific Palisades.

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In the meantime, saving existing trees remains the tree doctors’ priority.

Laura Travnitz, an Altadena resident who lost her home in the fire, recalled an Army Corps contractor pressuring her to remove more than a dozen fire-impacted trees on her lot. Now, they’re just stumps. Some already have little green shoots reaching up toward the sky.

“I’m 65,” she said. “I’m not going to be around for those to grow again.”

A 27-year-old woman began an experiment on herself early one morning in December 2024. Her laboratory was her childhood bedroom, tucked into a second-floor corner of a pale yellow house in the Boston suburbs. On a bookshelf behind her sat a small stuffed sloth and some favorite books, including “Siddhartha” by Hermann Hesse. Her parents were asleep in the room next door.

Her name is Rebecca, but she goes by Becks. Sitting at her desk in a gray T-shirt, she opened a small plastic bag filled with white powder. The bag was stamped “SR-17018,” and “NOT FOR HUMAN CONSUMPTION.”

She extracted some powder with a red microscooper, poured it onto a digital scale and carefully weighed out 25 milligrams. She gathered this into a blue and white pill capsule and sealed it, and then swallowed the capsule with water. It was 4:27 a.m.

“It’s my turn to be a guinea pig,” Becks wrote in the online diary she was keeping of her experience. In sharing her story with The New York Times, she asked that her last name not be used so potential employers don’t discover her drug history.

Becks had joined the vanguard of a dangerous, highly speculative do-it-yourself approach to getting sober. For a decade, on and off, she had been addicted to various drugs, most recently kratom, an opiate-like substance, which cleared her head and covered up her pain but required constant dosing. She feared the call of fentanyl, which she’d tried a few times.

“Every morning, I woke drenched in sweat from overnight withdrawals. It was a grim existence,” she wrote of her kratom use. She tried various methods to get sober, including three short inpatient detox stays and one monthlong rehabilitation treatment. She had periods of sobriety but couldn’t sustain it.

Then she heard about SR-17018, one of many new and unpredictable synthetic drugs made largely in China and sold online even though it is not approved or shown to be safe, and can pose lethal risks.

Most of these compounds, known as novel psychoactive substances, are designed to get people high. Among those substances, SR-17018 stands virtually alone in that people are using it to try to free themselves of addiction, and some claim it helps.

Excitement about SR-17018 grew after Reddit users discovered a 2019 study suggesting it could free drug-addicted mice of their dependence.