Protected: native coast live, blue, black and valley oak, bigleaf maple and incense cedar 11.5"+; coast redwood 18"+; any other tree 15"+ except listed invasive weeds and WUCOLS high-water-use species (diameter at 54"). Removal needs an Urban Forestry permit backed by a designated arborist's report, even for dead or hazardous trees.
How to apply: Apply to Palo Alto Urban Forestry for a protected tree removal permit with a tree report from a designated arborist.
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: codelibrary.amlegal.com/codes/paloalto/latest/paloalto_ca/0- · codelibrary.amlegal.com/codes/paloalto/latest/paloalto_ca/0-