Petaluma, CA Landscaping Rules: Tree Trimming (2026)

Two distinct ordinance regimes govern trees in unincorporated Sonoma County. (1) The Tree Protection Ordinance, codified at Sonoma County Zoning Code Sec. 26-88-010(m), requires a zoning permit and mitigation (replanting, preservation, or in-lieu fees) before removing protected tree species above the regulated diameter at breast height; the original 1989 ordinance protected 11 species at 9 inches dbh, and the comprehensive update adopted by the Board of Supervisors on April 16, 2024 expanded the list to 31 species at 6 inches dbh. Use permits are required for hardwoods at 36 inches dbh and redwoods at 48 inches dbh. (2) Chapter 26D (Heritage and Landmark Trees), adopted as Ordinance No. 3651 in 1986, prohibits removal of designated heritage or landmark trees without a permit issued under Sec. 26D-5 (subject to exemptions in Sec. 26D-6). (3) For defensible space, Chapter 13A and Permit Sonoma vegetation-management standards require tree branches to be limbed up six feet (6') from the ground, with branches removed within 10 feet of chimneys and stovepipe outlets and trees within 10 feet of neighboring structures on unimproved parcels pruned to at least 6 feet above grade.