You will need a permit to trim or cut down a tree if the tree is classified as a live Significant Tree or a Heritage Tree. A Significant Tree has a trunk circumference of 38 inches or more measured at 4-1/2 feet above the ground, except in the Emerald Lake Hills Design Review district, where the trunk circumference is 19 inches or more. Heritage trees include all Santa Cruz Cypress and Oregon White Oak, plus certain other trees depending upon their size and location. A detailed list of these, including their qualifying sizes, is available at the Planning counter. In some cases, you will need to submit a report prepared by a licensed arborist that assesses the general health of the tree(s). Where trees are proposed for removal due to proposed development, it is best to assess such removal when such development plans are also submitted. Please read the Significant Tree Regulations and Heritage Tree Regulations for more detailed information.
If the tree is in the public right-of-way or street, you need to contact the Department of Public Works at (650) 599-1852.