Burlingame assesses loss after series of storms

The rare gusting winds that reached 50 mph during a storm on March 14 brought down more than 40 trees in Burlingame and the city’s arborist is actively inspecting and pruning trees to prevent further failures.

The city has a detailed inspection and pruning schedule for the 17,000 trees it owns in the city but the oversaturated soils and roaring winds created a recipe of disaster for the many that have fallen over the last six weeks. Every one of those trees is scheduled for an inspection and trimming once every four years, the city’s arborist Richard Holtz said during a March 20 City Council meeting.

“It is the industry standard and it does work but we are facing these storm events of increased intensity that our urban forest and none of us around here ever had to face before,” Holtz said.

Some of the larger groves, like the trees along Easton Drive, are on an accelerated maintenance program. He added the maintenance program the trees are on works and lessens the likelihood of tree failure.

Of the 40 trees that fell, 25 were city owned, 14 were owned by homeowners and five were along El Camino Real, which is owned and maintained by Caltrans. Bayside Park lost 17 trees all in a row.

Those trees fell like dominoes one after another, Holtz said. He ensured the city is not just responding to fallen trees, but actively looking for potential failures.

“We are looking for active movement, movement in the soil, gaps and cracks opening up, which is very concerning,” Holtz said.

During the Feb. 21 storm, when gusts of wind reached 40 mph, the city identified and removed eight trees on Easton Drive that had active movement. During last week’s storm, the city identified three more trees that had active movement and were removed. A tree on Burlingame Avenue and in Washington Park were both removed. The city still plans on removing a tree on Easton Drive and trimming three on Burlingame Avenue but needs to work closely with Pacific Gas and Electric to de-energize the live electrical wires close to the trees. Residents who will be affected by the power outage will be notified in advance, Holtz said.

“Anytime we expect wind or significant rain we are out there checking these large groves,” Holtz said.

The city replaces trees but oftentimes with different varieties. Holtz said they no longer plant liquid amber trees because the roots have challenging infrastructure. The city also doesn’t replant the blue gum eucalyptus trees. Many of the trees are the large, shedding eucalyptus along El Camino Real. Holtz said the shallow-rooted blue gum trees can grow 300 feet tall and for 300 years. They shed a lot of flammable bark and the mess causes localized flooding and drainage issues. They also have caused problems pushing up the sidewalk and road from their roots and large diameter.

The city is looking to replace those identified problematic trees with a smaller Australian native tree called Corymbia citriodora, also known as a lemon-scented gum. These trees look similar to a eucalyptus and grow 75-100 feet tall. They are thinner in diameter and Holtz said they don’t have shedding issues and they are less likely to have branch failures. The variety is also being considered for the El Camino Real renewal project which plans to replace many of the eucalyptus trees along the state highway.

Holtz explained tree groves are all connected and removing one tree in a grove is similar to removing one leg from a four legged chair. That means the other three trees will take on more stress factors from wind, sunlight and shared roots, he added. When it is necessary to remove a tree in a grove, Holtz said the city will trim the trees that remain to lessen the effects from the wind.

If residents see gaps opening up at the base of the tree, he said it is best to call the police. He warned residents to stay away from the tree and be aware of surroundings.