Palo Alto’s City Council voted this month to remove all of the mature eucalyptus trees at Eleanor Pardee Park. While this would likely be a difficult decision in any city, it was controversial for Palo Alto—a city better known for fierce protection of its old trees, and last year’s outcry when the city cleared the mature trees lining California Ave. with little public notice or support.
This controversy began a year ago, when a falling tree branch from one of the towering trees nearly struck a man at Pardee Park. The distinctive smooth white and harlequin-colored trunks, some 4-feet in diameter, soar high above the other mature trees in the park.
Eucalyptus trees originally came from Australia. They were brought to California during the Gold Rush, and certain types are now considered invasive in California. Eucalyptus trees tend to fare well in California because of their ability to withstand drought and fire, according to a PBS article.
After a review of the Pardee trees’ health, Palo Alto’s Managing Arborist Eric Krebs advised the city, in what would be the first of three recommendations, to cut down six of the 16 eucalyptus trees because they showed sulfur fungus—a sign of wood rot.
He then advised the city to monitor the remaining 10 trees, which had been structurally damaged during an irresponsible pruning session decades ago. The city consulted the neighborhood about the proposal and removed the six trees Krebs suggested.
The plan to retain 10 trees would provide the park with shade and greenery while new trees had an opportunity to mature. Local resident Penny Proctor supported the partial tree removal at the council’s Jan. 10 meeting. “They’re so beautiful. I’ve seen them all my life. If you cut them down and plant something new, I’ll be dead before they get big,” she said.
But local mother Amy Kacher and other residents told the council they wondered whether safety should trump the plan to preserve the remaining 10 trees.
“I felt the city wasn’t taking safety seriously,” she said. “When I raised the issue, the city told me ‘you don’t have to come here. That’s your choice.’”
So at the cost of $700, Kacher hired Dave Muffly, master arborist for a local urban forest nonprofit “Canopy,” to write his own report as a private consultant. “My attitude was if Dave Muffly thought they were fine to stay, so would I,” she said. “Well, he didn’t.”
Muffly studied mechanical engineering at Stanford, initially thinking he’d go into automotive engineering. But during California’s drought in the late eighties and early nineties, he started noticing all the local trees that were dying because they had been selected without keeping in mind the reality of the climate.
He began participating in local tree plantings, and Canopy hired him in 1998.
Muffly wrote in his analysis (the park’s second) that when Kacher initially contacted him “my gut reaction was that the citizens were over-reacting.”
“But I stood there and looked at them,” Muffly added. When he factored in the tree rot and “lion tail” pruning that weakens the branching structure by encouraging branches to re-sprout, he began to have his doubts. He also considered the pedestrian paths directly underneath the tall canopies, and the number of branches that had fallen in previous years. “When considering if a tree will drop limbs in the future, I ask: has it shed one before? And the trees at Pardee Park fit that analysis.”
While using past limb failure to predict future limb failure may not seem to be a reliable test, tree failure experts say they generally consider the specific circumstances of individual trees, which include evidence of rot, stability and how many branches they’ve dropped in the past.
At the Jan. 10 city council meeting, more than a dozen local residents argued that eucalyptus trees were known for dropping limbs. Larry Costello, Co-Founder of the California Tree Failure Database, a project of the University of California, however, claimed that tree type indicates little. “The fact that they’re eucalyptuses isn’t the important part,” Costello said. “Look at the specific characteristics of each individual tree: structurally they’re different. One can have a high potential for failure, while another right next to it could be low.”
Mass tree removals tend to bother Costello. “You have to look at each tree as an individual,” he said.
For Muffly, the issue at stake was human-tree interaction. Muffly typically fights tree removals, because ultimately he says he wants to create a more “horticulturally savvy” society. “If we allow hazardous events to happen, however, then people will feel negatively about trees,” he said. “And today we need trees too badly.”
With the increased likelihood of extreme weather events due to climate change, he claimed the trees might be subjected to more severe storms than ever before.
“We can forecast likelihoods,” he wrote in his report. “And I can tell you without hesitation that you’re seriously tempting fate if any of the leaning trees are retained.
“It is my professional opinion that it will be a mistake to keep these trees. They are located in by far the most target-rich area.”
Later, he explained: “The stand I took for me personally was very controversial. Taking out big nice ones isn’t high up on my list of things to do—in fact it’s at the bottom. But so many scientists’ careers have been destroyed by clinging dogmatically to ideas. And so when this lands in my lap, I feel I have a responsibility.”
Muffly spent Christmas with his parents in his native Nebraska. “My last night in there (Dec. 28), I lost a little sleep. I knew there were big storms in the Bay Area. I worried I’d come back to a story.” And he did. That night a grandmother in Sonoma was killed when a tree fell on the tent she was sharing with her granddaughter.
After reading Muffly’s report, Kacher wanted to reach her neighbors. “I created and circulated a petition—it got 171 signatures,” she said.
To settle the dispute, the city hired a third arborist, Torrey Young. He found that the “high-traffic nature of the site combined with the method and long-term impacts of previous pruning renders inevitable the need to eventually remove these trees.”
“Torrey Young quantified what I had said in a very general way,” Muffly said.
The city plans to begin replacing the trees in March.
But Council Member Patrick Burt questioned the decision: “We have many mature trees, and one of the things that goes with that is that we do have risk from our trees.” Yes, he said, there are safety concerns. “But I do think that we have slipped over the edge here in terms of what our expectations should be.”
Six of the trees have already been felled. The remaining 10 face the ax in March.