Crews working to remove 12 eucalyptus trees off of San Mateo Co.'s Hwy 92

SAN MATEO COUNTY, Calif. (KGO) -- Some dangerous eucalyptus trees are in the process of being cut proactively down all week in San Mateo County.

It's happening on Highway 92, near Crystal Springs Reservoir.

"The tree is very heavy, top-heavy, and their root system is shallow. So, it doesn't come to a surprise for many arborists when they hear of a eucalyptus failure," said Frank Vasquez, president of Vasquez Arbor Care.

Vasquez care says eucalyptuses are not native to California and have always posed challenges, which is why Caltrans is hoping to stay on defense and get ahead of any trees which they say pose a significant risk.

On Wednesday, crews worked to cut a total of 12 eucalyptus trees down, trucking in very large equipment onto Highway 92 near Skyline Boulevard, which requires more time to position and set up.

MORE: 11 rescued after large tree falls on 5 vehicles at SF's Golden Gate Park, firefighters say

"Same thing with humans and trees. So many of us don't know what's going on inside of us -- Is there decay in the tree, or the root system? -- unless you excavate," Vasquez said.

But on one of the main routes to the coast in Half Moon Bay, drivers are asked to plan for delays or simply take a different route. One-way traffic controls are in effect from 6:30 a.m. to 3 p.m. daily through Friday.

"The crews will work as quickly and safely as possible to complete the work," said Alejandro Lopez, a Caltrans spokesperson. "We will work with the contractor to relieve congestion when possible by allowing additional time for the commute direction."

This is all to prevent the scary scene from happening to a busy highway.

Drivers saw Monday in San Francisco's Golden Gate Park, when a nearly 100-foot-tall, 80-year-old eucalyptus was fully uprooted and fell onto five cars, trapping 11 people in their vehicles.

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