Creating a defensible space

Defensible space is a term used to describe the careful selection, location and maintenance of vegetation and other combustible materials on the property. The purposes of a defensible space are:

  • Minimize fire pathways to the house
  • Reduce potential heat exposures to house components
  • Reduce the potential for embers to ignite materials adjacent to the house
  • Provide a safe place for fire personnel to defend the home and allow evacuation 

The priority is to start at the house and work outwards giving the greatest effort to avoid combustible vegetation and other materials within five feet of the house and any attached decks. The California Department of Forestry and Fire Protection defines three zones of a defensible space, respectively Zone 0 (0-5 ft), Zone 1 (5-30 ft), and Zone 2 (30-100+ ft).

UC ANR publication #8695

Zone 0 (0-5 ft)

Avoid anything combustible in this zone: woody plants, mulch, woodpiles, combustible trellises, and stored items. Zone 0 is an excellent location for walkways, hardscaping with pavers, rock mulch, or pea gravel. Zone 0 should be coupled with a 6" vertical noncombustible section at the intersection between the ground and the exterior siding.

Zone 1 (5-30 ft)

This zone should be "lean and clean". The goal is to eliminate fire paths between vegetation by increasing the spacing between trees, removing lower branches of trees and shrubs, and creating separations between vegetation groups. Plants should be properly irrigated and maintained to remove dead/dry material.

Zone 2 (30-100+ ft)

The goal is to moderate potential fire spread and flame height by reducing the density of trees, shrubs, and herbaceous plants or grasses. Shrubs and trees should be well spaced and pruned to eliminate fuel ladders. If Zone 2 extends over your property, prioritize implementing the recommendations for Zone 0 and 1. After completing these actions, connect with neighbors, HOA, or Fire Safe Councils to address concerns in your community.


For larger properties: Consider creating a Stewardship Plan (I.E. Forest Management Plan, Rangeland Management Plan, Oak Woodland Management Plan etc) for the property. These plans will help you determine your goals and objectives for that space and what tools and methods you might want to use. For more information about land stewardship and plans, visit the UCCE Forest Stewardship page.

It is important to remember that not every acre can be or needs to be treated for every goal and objective you may have for your property. If fuel reduction and fire mitigation is one of your goals and objectives for your land, doing strategic placement of treatments can go a long way in mitigating high severity fire on your property. Here are some fuel reduction priorities to consider:

  • Create strategic shaded fuel breaks by thinning and pruning trees and shrubs, and mowing/grazing grass next to:
    • Access roads (ingress and egress)
    • Ridgelines and other critical control points identified by local fire departments
    • Critical infrastructure on the property (water tanks, propane/fuel tanks, solar panels etc).  
  • Inform your local fire department of any water sources you have on your property that they could use in an emergency situation.
  • Working with neighbors or your local fire safe council to mitigate hazards for an area rather than just your property.

First responders access

Road access is crucial for your personal safety as well as those of first responders. Ensure that there is enough space for firefighting equipment to move onto your lot, as close as possible to your home and multiple access points to your parcel. During incidents, power lines or trees falling across roads are not uncommon. Work to develop:

  • Two or more roads in and out of your parcel provides an alternate route in case of emergency. Dead-end roads should have a turnaround as approved by the local fire authority
  • Each road should be accessible year round and at least 20 feet wide
  • Road grades should be less than 5% (5 foot rise for each 100-foot distance) are more accessible for larger fire equipment

Steep slopes and wind

If the home is located on a slope, in a drainage, in a windy area, or an area surrounded by unusually dense, tall, or combustible vegetation, thinning and spacing requirements increase. Additionally, if the home is in a vegetation type that is especially prone to wildfire or has an active fire history, a greater clearance and separation between plants and plant groupings may be beneficial. However, the areas cleared from vegetation should be monitored and maintained to prevent the spread of invasive and flammable grasses. When the home is at the top of a slope, keep in mind that fire and heat rise, allowing for pre-heating of the upslope fuels, resulting in the potential for more intense fire behavior. In these cases, greater effort should be directed at the area downslope of the home with even higher levels of fuel treatments given to the area below a deck.

Wind is another factor to consider alongside aspect and slope. A south-facing slope with southerly winds can easily span the 30 foot "lean and clean" recommendation. Work with your local resource experts to install adequate measures if your property is at risk.