Private trees of any species more than 12" in diameter (38" circumference), measured at the widest point between 6" and 36" above the ground, need a permit before pruning or removal. The permit is free. Replanting at least one tree per tree removed is a normal condition.
How to apply: Submit a tree permit request to the Redwood City arborist. The permit is free.
How to measure: most Bay Area cities measure trunk diameter (or circumference) at 4.5 ft (54") above natural grade, but some measure elsewhere: Berkeley at 4 ft, Redwood City at the widest point between 6" and 36". Where a city sets its limit by circumference, we show the diameter (circumference ÷ 3.14).
Official sources: redwoodcity.org/departments/community-development-department