“Adequate defensible space acts as a barrier to slow or halt the progress of fire that would otherwise engulf your property and your neighbors.” [Defensible Space — Fire Safe Berkeley]
Without appropriate defensive space, BFD makes it clear that our properties may not defensible, and therefore not defended: “during a wildfire, firefighters are forced to triage properties and typically will choose properties better prepared against wildfire - because they can be effectively protected.” [Defensible Space — Fire Safe Berkeley]
Over the past 30 years, wildfire research has matured and developed solid quantitative measurements. Defensive space is divided into three zones. Enforcing them is actually a legal requirement in California [Public Resources code (PRC) 4291].
This metal gate and fence allows the homeowner to make the fence abut the house without breaking Zone 0 regulations
Zone Zero: 0-5 ft “ember resistant”
Wind-blown embers accumulate near the walls of a house, and may eventually ignite it. The first 5 feet near a structure are the most important. It should be bereft of any combustible materials, including plants of any kind, furniture, or other structures. This is actually a CA law that has been on the books for several years, but without rules for enforcement: it was unclear if CA would ever put teeth into it. It is now clear, however, the Governor Newsom intends to fully enforce it: Newsom to enforce fire safety regulations post LA wildfires | cbs8.com
Zone 1: 5-30 ft “lean, clean and green”
Thin out and space trees and shrubs in this zone. Limb trees and shrubs appropriately. Remove understudy wherever it may risk igniting vegetation above it. Remove debris. If possibvle remove all combustible furniture. Do not allow accessory combustible structures in this zone. All this activity is tightly regulated in Berkeley and in most other Wildland Urban Interfaces in California, with specific requirements to adhere to [PDF].
Zone 2: 30-100 ft “fuel reduction”
Reduce fuel up to 100ft away from your home or to the property line. Cut grass to four inches or less. Create horizontal space between shrubs and trees. Create vertical space between grass, shrubs and trees. Remove all debris. Follow isolation rules around wood piles, outbuildings and propane tanks. Like for Zone 1, these activities are tightly regulated in Berkeley [PDF], and California in general.
