Like many Los Altos residents, I love our trees and enjoy their majestic natural beauty and the privacy their foliage provides. We take care of the large trees in our yard; they are inspected regularly to ensure their health.
However, we recently learned that even well-maintained trees can topple over – particularly during a strong storm.
On a Sunday in early January, I was awakened by a loud crash at 6:30 a.m.
Upon investigation, my family and I discovered that a large Coast Live Oak had split in half and landed on the roof – right above the master bedroom. It also crushed a wrought-iron patio table and chairs set in the backyard.
Once my family and I settled down from the frenzy and examined the damage, we wondered if other parts of the house could suffer a similar fate. We confined ourselves to the family room, an area of the house with the fewest trees overhead, and soon contacted a tree-care company. Many of the smaller companies were unable to respond quickly – the storm was a boon for business – but the South Bay branch of Davey Tree Expert Co. was available.
According to Roy Bradshaw, one of the company’s arborists, our oak tree had what he called “included bark” that “causes the limbs to actually split apart.” In our case, it caused a “poorly attached” limb to fall, he said.
The experienced arborist (more than 30 years in the business) listed several other reasons trees may fall.
“Most trees need something going on with the roots system for them to fall over,” Bradshaw said.
Oversaturated soil combined with wind is another common cause, he added.
Although Bradshaw said he sees more fallen trees in Los Altos Hills than he does in “maintained areas” such as Los Altos and Mountain View, he believes that the recent storms and California’s ongoing drought contribute to the toll.
He described how the drought causes the trees’ root systems and canopies to “die back,” leaving them in bad shape for the saturated soil caused by a storm.
“The tree just sucks up as much water as it can, and then it sends this water to the foliage and the upper canopy,” Bradshaw said. “The tree just cannot handle all this weight, and the canopy topples over.”
So what can homeowners do to help prevent a tree from falling on their roofs?
“What you want to do is have a safe tree to begin with ... (making sure it’s) fertilized and maintained,” he noted. “Keep the tree pruned so that airflow through the canopy can actually flow through the tree.”
He warned of the “wind-sail effect,” whereby winds topple over trees without enough canopy airflow.
Other ways to keep trees healthy include pruning them every three to five years and adjusting watering schedules based on the weather, according to Bradshaw. During dry seasons, for example, Davey Tree focuses on supplemental watering and deep root fertilization to help with “grounding conditions,” Bradshaw said, adding that it’s also important to remove deadwood from trees, as it can act as a home for insects.
For oak and cedar trees, it is especially important to keep the ends trimmed because they grow horizontally, resulting in a lot of “in weight,” Bradshaw said.
Homeowners who want to remove the tree altogether, however, should contact their city’s planning department to ensure that they are complying with city codes and ordinances.
Like many of my neighbors, I feel fortunate to have so many big and beautiful trees in my yard and look forward to enjoying summertime dinners in the shade of its majestic foliage. But we’ll have to get a new patio set first.