The information below was taken from Cal Fire Defensible Space
Zone 0: Start Closest to Your Home to be Ember-resistant
The first five feet from your home is the most important. Keeping the area closest to buildings, structures, and decks clear will prevent embers from igniting materials that can spread the fire to your home.
Why? The majority of homes lost to wildfire are ignited by flying embers. Embers can travel miles ahead of the active front of wildfires.
What to do:
- Use hardscape like gravel, pavers, or concrete. No combustible bark or mulch.
- Remove all dead and dying plants, weeds, and debris (leaves, needles, etc.) from your roof, gutter, deck, porch, stairways, and under any areas of your home.
- Remove all branches within 10 feet of any chimney or stovepipe outlet.
- Limit combustible items (like outdoor furniture and planters) on top of decks.
- Relocate firewood and lumber to Zone 2.
- Replace combustible fencing, gates, and arbors attached to the home with noncombustible alternatives.
- Consider relocating garbage and recycling containers outside this zone.
- Consider relocating boats, RVs, vehicles, and other combustible items outside this zone.
Zone 1: Keep it Lean, Clean and Green Within 30 feet
Regularly clear dead or dry vegetation and create space between trees. During times of drought when watering is limited, pay special attention to clearing dead or dying material.
Why? Removing dead plants and creating space between trees and shrubs creates a buffer for your property and reduces potential fuel for fire.
What to do:
- Remove all dead plants, grass, and weeds.
- Remove dead or dry leaves and pine needles.
- Trim trees regularly to keep branches a minimum of 10 feet from other trees.
- Create a separation between trees, shrubs, and items that could catch fire, such as patio furniture, wood piles, swing sets, etc.
Zone 2: Reduce Potential Fuel Within 100 feet
Continue reducing potential fuel within 100 feet or the property line.
Why? 100 feet of defensible space is required by law. Public Resources Code (PRC) 4291
What to do:
- Cut or mow annual grass down to a maximum height of four inches.
- Create horizontal space between shrubs and trees. (See diagram)
- Create vertical space between grass, shrubs and trees. (See diagram)
- Remove fallen leaves, needles, twigs, bark, cones, and small branches. However, they may be permitted to a depth of three inches.
- Keep 10 feet of clearance around exposed wood piles, down to bare mineral soil, in all directions.
- Clear areas around outbuildings and propane tanks. Keep 10 feet of clearance to bare mineral soil and no flammable vegetation for an additional 10 feet around their exterior.
Vertical Spacing
Maintain space between the lowest tree branches and the ground or shrubs.
- Remove all tree branches at least six feet from the ground.
- Allow extra vertical space between shrubs and trees. Lack of vertical space can allow a fire to move from the ground to the brush to the treetops like a ladder. This leads to more intense fire closer to your home.
- Keep at least three times the height of any shrubs between the shrubs and the lowest branches of trees.
- Example: A 5-foot shrub is growing near a tree. 15 feet of clearance is needed between the top of the shrub and the lowest tree branch.
Horizontal Spacing
Horizontal space depends on the slope of the land and the height of the shrubs or trees. Leave more space between vegetation on bigger slopes. Refer to the chart below to determine spacing distance.
Space between shrubs:
- Flat or mild slope (less than 20%): Two times the height of the shrub.
- Mild to moderate slope (20-40%): Four times the height of the shrub
- Moderate to steep slope (greater than 40%): Six times the height of the shrub
Space between trees:
- Flat or mild slope (less than 20%): 10 feet.
- Mild to moderate slope (20-40%): 20 feet.
- Moderate to steep slope (greater than 40%): 30 feet.