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When the Los Angeles wildfires broke out on the morning of 7 January, some of the most dramatic images were of palm trees set ablaze along Sunset Boulevard. In the days that followed, burning palms became a symbol to illustrate what may be the costliest wildfires in history, which left at least 25 dead and destroyed thousands of structures.
The trees are icons of the city. They also played a role in spreading the flames, researchers and fire officials say.
While a deadly combination of factors caused the fires, many palm species are fire-prone and difficult to extinguish once ignited. Poorly maintained palms, which have dead, dry material under their canopies, are notorious for being receptive to embers, the primary cause of structure loss in wildfires. In high winds, small chunks of burning fibers or large fiery fronds can travel long distances.
“One Mexican fan palm frond is equivalent to a whole branch getting caught in the wind and moving, and when that gets caught on a roof, under an eave or any other flammable material, that’s much more significant than a pine needle or a sycamore leaf,” said Esther Margulies, a landscape architect and University of Southern California (USC) professor who specializes in climate and wildfire resilience planning. “Unfortunately, it makes logical sense” that they helped spread the fires.
Research has shown that southern California’s palms – which are all non-native, except for the California fan palm that grows in the desert – “go up like Roman candles” when embers hit dead fronds. Palm trees have also ignited because of lightning strikes, power lines, fireworks and arson. The Los Angeles fire department says palms should not be used in known fire hazard severity zones.
But not all palms are created equally. One that is intensively maintained and healthy may not catch fire like a palm in its natural conditions, where it has a big skirt of fronds hanging down.
That has fueled wild conspiracy theories. Although thousands of palm trees have probably caught fire this month, some images of unscathed palms located next to destroyed homes stoked false claims about the fires being intentionally set by the government to initiate a “land grab” or to stop the development of China-funded, high-speed rail.
The real reasons why some palms didn’t burn are varied. The way they were pruned, how much moisture the tree had internally and the unpredictability of wind patterns all impact flammability. If the tree was stressed, or leaking resins from a previous wound, that could play a role, too. Generally, healthy trees are less likely to ignite.
The future of LA’s palms
Meanwhile, the fires are shining light on another palm tree problem.
It’s hard to imagine Los Angeles without its celebrated palm trees, but that could become a reality as they are under threat from fires, disease, pests, aging and the fact that they are wildly impractical in a sprawling city that desperately needs more cooling benefits than palms can provide. They are also dangerous even when the city is fire-free. Residents have reported heavy fronds with thorny spines falling from 80-plus-foot heights, breaking roof tiles, piercing car windows and narrowly missing people in the process.
Many palms were first planted in the Los Angeles area in the 18th century by Spanish missionaries who used the fronds in religious services. By the early 1900s, they were used as decorative plants by the wealthy and real estate developers, who marketed the city as a tropical paradise.
The 25,000 trees planted in advance of the 1932 Los Angeles Olympics and the additional 40,000 that were added as part of the New Deal’s Works Progress Administration are now considered “senior citizens”. Tree experts say it’s never a good idea to plant so many of the same species simultaneously because of pests, disease and the fact that they will age out at the same time. A 1990 city tally estimated that there were 75,000 palm trees on city streets, but it’s unknown exactly how many are left standing, especially after the latest wildfires. A USC study of an urban area near downtown Los Angeles found that 12% of the street tree canopy consisted of highly flammable palms, Margulies said.
Palms are actually grass, not trees, and they’ve been called out by environmentalists for their high water usage, inability to store large amounts of carbon dioxide and lack of shade. The Canary Island date palm, seen throughout the Beverly Hills and Hancock Park neighborhoods, is the one palm that can create a valuable shade canopy, but because of the trees’ potential dangers and high cost – a mature one can cost upwards of $20,000, which is why some have been stolen in the past – they are unsustainable.
No one knows exactly when the palms will die, but when they do, some streets will have zero shade. The city or county of LA, which already has limited resources for maintaining its urban forest, will need to remove a significant volume of 100ft tall palm trees to be processed, disposed of or upcycled.
“I am sympathetic to the aesthetic history of LA and I’m not of the mind that we should eradicate palms from the entirety of our landscape, but we should be more selective where they’re used,” said Bryan Vejar, master arborist and associate director of community forestry at TreePeople, an environmental non-profit. “They shouldn’t be used on streets where we need to mitigate some of the heat island effects.”
People have strong opinions about the compositions of urban forests, with some believing LA should only plant native trees. Others say to only plant trees from the world’s hottest and driest places. Vejar believes we can do both and advocates for replacing the majority of the city’s palms with native oaks, desert willows and toyon, as well as extremely drought-tolerant non-natives such as the Chinese pistashe. Of course that would change the look and iconography of the city, but perhaps that’s the point: LA, advocates argue, should look more natural with a canopy that provides more benefits to all Angelenos.
It’s unlikely that palms will disappear entirely. Homeowners and developers will probably continue to plant them on private property, despite the threats to and from them. The city has committed to maintaining palm trees in areas with historical significance such as Hollywood and parts of downtown, but otherwise is focused on planting climate-resilient species and creating an equitable urban forest.
“Most palm trees have never been a good solution,” said Margulies. “We need to change the perception of LA. When it comes to living things, we really should have a deep respect for the trees that are native and indigenous to this area and really will thrive here.”
