Members of the Parks, Beaches and Recreation Commission received an update on the removal of the blue gum eucalyptus trees on Groves Bike Trail on Tuesday, which included an announcement that one of the trees, which had not been marked for removal, had fallen.
“There was no indication (of) the conks or some of the other visible issues,” like decay, that had previously been discussed, said Mark Harmon, general services director for the city.
Even more concerning, Harmon continued, was the fact that the tree had no root structure at all. There was very little dirt lifted up when it fell, he added.
“And that’s the problem with the blue gum eucalyptus, they lose that root structure over a period of time,” he explained.
“Well, now I’m freaked out,” said PBR vice chairman, Tom Anderson. “That bike path has a lot of people on it on the weekend. A lot.”
“That’s a big concern,” he continued. “That’s very disquieting.”
Earlier in the meeting, the commission unanimously approved adding coast live oaks as replacement trees on the trail. They will also be replaced with torrey pine and London plane trees that were previously approved.
City watchdog Jim Mosher was the lone public commenter on the issue, noting that the oak is “famous for being subject to fungus,” which is the problem the city has had with the “beautiful, but dangerous” blue gum eucalyptus trees.
This most recent tree falling “could mean that they’re all dangerous, or it could mean that the arborists just don’t know what they’re talking about,” Mosher said.
Staff will not do the four-phased approach to removal as originally planned, Harmon reported, in which they would have removed some and then replaced them before moving on to the next phase. They will now speed up the removal of all 54 trees and quickly follow that with the irrigation and replacement.
“This isn’t a delay in replacing those trees at all,” Harmon said. “But in discussions with the city manager and others, we feel the need now to not phase those in but to remove those trees.”
They will also bring back Dan Jensen, the outside arborist who originally looked at those trees more than a year ago, to take another look at the remaining blue gum eucalyptus on that trail and report back to the city.
“That tree failure was very concerning, to say the least,” Harmon said.
This is the last section, grove or row of blue gum eucalyptus trees in the city, Harmon said, after these are gone they will only be located in wide open areas or will standalone.
“With trees, you don’t know what’s going on underneath the ground, that’s always been a concern,” Harmon said. “There’s no 100 percent guarantee that we know that kind of information. But, yeah, it was kind of spooky.”
Mosher remembered that when they debated removing the trees on Holiday Road they discussed that there are ways of testing the integrity of the part of the tree above the ground, like a resistograph, that can detect decay.
“I have to assume that when we can put rovers on Mars there must be a way to tell if a tree has roots or not,” Mosher said.
The city will look closely at the other trees on the trail and follow up after Jensen makes his report.