Topless in Beverly Hills
The majestic palm trees lining the boulevards of Beverly Hills are more than just landscaping--they’re the city’s prize flora, immortalized on postcards and film, a ubiquitous image synonymous with Southern California.
But now the massive Canary Island date palms are threatened by a deadly disease that is eating away their cores and, in the worst cases, causing their feathered crowns to snap off in strong gales, sending the one-ton palm heads hurtling as much as 70 feet to the ground.
So far, 11 trees have lost their heads in the last few years and dozens more are suffering from the mysterious malady that has baffled the wealthy Westside city. Luckily, no one has been hurt and no property damaged--thanks in part to the city’s ban on street parking.
Beverly Hills has launched an all-out effort to save the 90-year-old trees, some of the oldest palms in Southern California. Last June, the city hired three arborists to track down the cause of the falling tree tops--and so far, they’re still stumped.
Experts, including Michael Mahoney, an arborist working with the city, suspect that the culprit is a fungus found in many of the affected trees--Thielaviopsis paradoxa--that is known to cause dead spots in palm trunks. Leading authorities on palm tree diseases said occurrences of so-called sudden crown drop are rare and have been documented only a few times in Southern California in recent years.
Some arborists said it is unclear how contagious the fungus may be, and speculated that it may enter through an open wound in the tree. But one authority who observed the disease as a professor in Florida said it is not contagious and does not threaten other healthy palms.
“The only way it’s really spread is mechanically, through tree spikes or other devices,” said San Diego-based horticulturalist Henry Donselman, who was a Florida state palm specialist for 15 years.
Despite its infrequency, Donselman said this “bud rot” poses a potential danger because it can go undetected for so long. Healthy Canary Island palms can live as long as 150 years, he said.
When arborists pulled down the headless trees in Beverly Hills, they discovered that nearly all of the normally strong, green fibers inside the trunks had turned into dry, brown rot.
“[The fungus] doesn’t usually cause the tops to fall off,” Mahoney said. “But the trees obviously are under more stress when they’re grown in the city than in nature.”
Mahoney said he has heard only a handful of reports of sudden crown drop in other Southern California cities. The most serious incident occurred in Carlsbad in 1994, when a palm head toppled over and killed a woman as she was sunning by a beach resort pool. In Los Angeles, there have been a few isolated cases of falling palm heads, according to a spokesman for the city’s Public Works Department, but no evidence of a widespread problem.
But in Beverly Hills, where 1,300 aging date palms are packed into five square miles, the trees have been hit hard by the strange phenomenon, prompting the city to spearhead one of the first studies in California of sudden crown drop. Scientists suspect that the pesky fungus is more malevolent in older trees, spreading through such a large part of the trunk that the palm can no longer support its head.
“Locally, [sudden crown drop] is a very minor occurrence,” said Howard Ohr, a plant pathologist at UC Riverside who is a national authority on palm disease. “It certainly should be a major concern if it’s in so many trees. It [rots] without showing any external symptoms, and so by the time you figure what’s happened, it’s too late.”
The crown drop phenomenon presents yet another danger to the landmark trees in Beverly Hills, where about 100 a year already succumb to a disease that attacks the vascular system. The fusarium wilt fungus, which is spread through pruning or airborne pathogens, causes the fronds to wilt and kills about 10% of the city’s Canary Island date palms annually, but workers are able to control it by sterilizing pruning instruments.
The new threat, however, is more worrisome because no one knows how many trees may be affected.
As part of the study, workers routinely test the date palms by knocking rubber mallets against the base of the head and listening for a hollow echo that signals a rotting trunk. If the sound indicates a potential problem, workers prod the trunks with ice pick-like tools to see how deep the damage goes. Palms that show signs of the fungus are regularly inspected.
Meanwhile, Mahoney and the rest of his team--which includes a plant pathologist and an environmental horticulturist--are assembling a database tracking all the infected palms. They’ve called the Canary Islands to see if trees in the palms’ native home have problems with sudden crown drop. Officials there told the city they had not encountered such problems.
“The city takes pride in these trees,” said Robert Chavez, the city’s parks and urban forest manager. “Any photo of Beverly Hills has palms in the picture. . . . It represents what this city is, the stature and the stateliness of Beverly Hills.”
Arborists in Southern California are closely watching to see how Beverly Hills protects its elderly trees.
“It’s scary, definitely, because we have so many palms here,” said Johnny Aguila, city arborist for Santa Monica, where the lanky trees are an indelible part of the city’s beach image. “We haven’t had lost any heads yet, but we’re waiting to see what Beverly Hills comes up with--hopefully they’ll find a cure or a way to prevent it.”
Now, Chavez and the consultants are trying to determine if they will have to replace the missing palms with a more resilient species--something that could dramatically alter the city’s landscape. “It’s hard for us to know that we might not be able to put these palms back in,” said Chavez, gesturing to the corridor of palms on Beverly Drive. “We want to do whatever we can to save them.”
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Palm Problem
A disease is eating away at Southern California’s majestic date palms, weakening the trees and costing some of them their crowns. The likely culprit: Thielaviopsis paradoxa (a fungus).
What It Does: Fungus slowly eats away the trunk of the tree, causing dead spots. In Beverly Hills, only the innermost core of the infected trees is not yet rotted.
How It Spreads: Palm experts say the fungus enters a tree through a wound in the trunk and spreads from there. But how it spreads from tree to tree is uncertain--perhaps through the air, from the ground or via watering.
Why the Fronds Fall: The fungus acts over a number of years, weakening the trees and making them susceptible to high winds. The tops of infected trees in Beverly Hills broke off during high winds about two feet below the base of the crown.
Part of trunk susceptible to damage
Palmae canariensis, the Canary Island date palm
Height: 50-60 feet
Age: Some of the Beverly Hills trees are 90 years old.
