A young Davis family narrowly escaped potential serious harm last week after a large branch fell from a tree they’d been sitting under in an East Davis park.
Charles Campbell, his girlfriend Rachel Ottlinger and her son were enjoying the shade under a Chinese pistache in Chestnut Park on Sept. 10, playing with two kids who lived in the neighborhood. But a loud crack in the canopy above them sent all five scurrying out from underneath the tree.
The two young kids scampered off in one direction, Ottlinger’s son, Logan, ran in the other and Campbell trailed right behind him.
Ottlinger, on the other hand, had only enough time to roll over before a long branch, measuring about 5 to 6 inches in diameter, slammed down beside her and on top of a backpack and other belongings the group had with them.
“I felt a branch just graze my side and there was a really heavy part that just landed right there,” Ottlinger said this week during a return to the scene, pointing to the ground where the branch fell. “It would have landed right on my hip and probably killed me.”
Added Campbell: “I saw it coming down and I saw her and I thought she got clipped. I thought it hit her for sure.”
Fortunately, Ottlinger, Campbell, Logan and the kids escaped the incident unscathed.
But while the couple are beginning to shake off the event, the two longtime Davis residents have been looking for answers about why the branch came down in the first place. The weather that afternoon, they say, had been pleasant.
According to Rob Cain, the city’s urban forest manager, the branch fell because of a phenomenon called “limb drop” where, to combat hot, dry weather, a tree sucks up and holds large amounts of water in its trunk and branches.
If the limbs become too heavy, they can overwhelm and break off from the tree.
“When we get our hot weather we’ve been having, with no air flow, trees shut down and don’t transport water,” Cain said Tuesday. “As they’re uptaking water to continue their processes, the trees fill up with water and fill up their limbs.”
Cain also said, historically, Davis experiences this phenomenon only a few times each summer season, or about once a month.
But perhaps more disturbing about limb drop than the frequency is the unpredictability of it.
“Unfortunately, there’s no real way to determine when this is going to happen,” Cain said.
The phenomenon isn’t specific to one type of tree either. Native oak trees most commonly experience limb drop, but other trees like the Chinese pistache, pear trees and ash trees are susceptible as well.
Last month, The Sacramento Bee reported an incident where a student at Chico State University was killed by a branch that fell from an oak tree on campus oak tree.
Last week, an ash tree lost a limb on F Street in downtown Davis, landing on the roof of a parked car. No one was hurt.
Meanwhile, irking Campbell and Ottlinger even further, the tree they were sitting under in Chestnut Park had suffered one recent fallen limb already. A third branch had fallen from the tree in the past, but Cain couldn’t determine the cause.
Cain said maintenance crews are supposed to report substantial breaks to him so he can inspect the tree. But the city’s resident arborist was not alerted to this particular tree until last week’s incident.
One of the ways to help guard against limb drop is to ensure that all trees have received proper trimming and pruning to reduce the weight on the branches as much as possible.
Last year, the city laid off two members of its tree trimming crew to help offset the $800,000 it paid to members of the Davis City Employees Association after it was found that the city had illegally imposed an employee contract on the group in 2010.
But while city staff resources were reduced because of the terminations, Cain said the City Council simultaneously directed public works employees, and the private company the city hired after firing the tree trimmers, to pay closer attention to trees in parks.
As a result, Cain said service has improved since the tree trimmers were let go.
In the past, trees in parks were pruned on a reactive basis, but the new directive calls for park trees to be pruned every seven years. Street trees are pruned on a seven-year schedule as well.
“Trees hold that prune (on the seven-year cycle) pretty well,” Cain said.
However, Cain also said the city hasn’t reached that frequency yet. The last time trees were pruned in Chestnut Park was 2008.
As for future incidents, Cain said because of the upcoming cool and rainy season, he doesn’t expect many more limb drops to occur.
Laura Westrup, who chairs the city’s Tree Commission, says while these incidents aren’t unique to Davis — she’s heard of limb drops happening commonly in the Bay Area and in Sacramento — it comes as part of the territory of caring for a tall tree canopy in town.
“Any parent, anybody who has kids, would be concerned about this, around greenbelts and parks,” Westrup said. “But considering all the street trees we have, it’s common to have this limb drop.
“It goes with having this beautiful urban forest here in Davis.”
— Reach Tom Sakash at firstname.lastname@example.org or 530-747-8057. Follow him on Twitter at @TomSakash