The code skeleton
The California Board of Forestry approved the Zone 0 rules on 2026-08-19. Within 5 ft of a structure they require removal of combustible mulch, firewood and dead vegetation and prohibit new combustible fencing (the Board of Forestry Zone 0 regulations, August 2026).
The rules apply to qualifying structures in State Responsibility Areas and in Very High Fire Hazard Severity Zones in local areas (the California Wildfire and Forest Resilience Task Force).
The rules take effect for new construction once they are filed with the Office of Administrative Law and phase in later for existing homes. The filing date is unconfirmed until the Office confirms it (the Board of Forestry Zone 0 regulations, August 2026; the California Wildfire and Forest Resilience Task Force).
The Very High Fire Hazard Severity Zone is a fire district. Structures there follow the California Wildland-Urban Interface Code, and paints and coatings are not an approved protection method (Los Angeles Municipal Code 91.7207).
A Forest Products Laboratory study found that charring cedar, called shou sugi ban, did not systematically improve the flammability or durability of siding (USDA Forest Products Laboratory).