As developed by San Diego County Fire Authority partner, Cal Fire:
Defensible space is essential to improve your home’s chance of surviving a wildfire. It’s the buffer you create between a building on your property and the grass, trees, shrubs, or any wildland area that surround it. This space is needed to slow or stop the spread of wildfire and it protects your home from catching fire – either from direct flame contact or radiant heat. Defensible space is also important for the protection of the firefighters defending your home.
Defensible Space Zones
Two zones make up the required 100 feet of defensible space.
Zone 1 extends 30 feet* out from buildings, structures, decks, etc.
* San Diego County requires 50 feet of clearance in zone 1. Check with your local fire department for any additional defensible space or weed abatement ordinances.
Plant and Tree Spacing
The spacing between grass, shrubs, and trees is crucial to reduce the spread of wildfires. The spacing needed is determined by the type and size of brush and trees, as well as the slope of the land. For example, a property on a steep slope with larger vegetation requires greater spacing between trees and shrubs than a level property that has small, sparse vegetation.
Remove all tree branches at least 6 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 tree tops like a ladder.
To determine the proper vertical spacing between shrubs and the lowest branches of trees, use the formula below.
Example: A five foot shrub is growing near a tree. 3x5 = 15 feet of clearance needed between the top of the shrub and the lowest tree branch.
Horizontal spacing depends on the slope of the land and the height of the shrubs or trees. Check the chart below to determine spacing distance.
Fire-safe landscaping isn't necessarily the same thing as a well-maintained yard. Fire-safe landscaping uses fire-resistant plants that are strategically planted to resist the spread of fire to your home.
The good news is that you don't need to spend a lot of money to make your landscape fire-safe. And fire-safe landscaping can increase your property value and conserve water while beautifying your home.