University of California
Fire in California

Preparing Your Landscape

In fire prone rural or wildland/urban interface areas, homes and other structures should be surrounded by landscaping designed to resist or slow fire. A fire-resistant landscape not only reduces the risk to your home, but enables firefighters a place from which to defend your structures. Use a house-out approach - this means, make sure the structure itself is hardened against fire, then implement the guidelines here in concentric circles moving away from your structures.

To create a fire-resistant landscape:

  1. Choose fire resistant landscape features (mulch, pavement, planters, etc.) and plants. 
  2. Arrange landscape features with horizontal and vertical space to disrupt a fire. 
  3. Maintain landscape features - keep plants, alive, healthy, and well pruned. Don't allow construction materials, recreational equipment, or other debris to accumulate. 
  4. Avoid elements that conflict with 1-3 - for example, avoid invasive weedy plants that might take over an area. 

Defensible Space is only part of a larger landscape management strategy, designed to protect your home and property. The general surroundings leading up to your home must be considered as part of your wildfire preparedness planning.

Vegetation Management

As a rule of thumb, you need to make sure that a fire moving toward your home cannot follow a continuous path through vegetation. Make sure that plants are small and in broken clusters (a mosaic arrangement). The closer to the home, the smaller the plants and clusters should be.

This mosaic applies in both the vertical and horizontal space. Placing shrubs directly adjacent to a tree vastly increased the chance of a fire moving into the crown of the tree. Trees have potential to release a great amount of heat toward any combustible material within a 30-foot area and certain types of trees (such as cypress and eucalypts) generate many burning embers that can overwhelm your (or your neighbors’) structures.

First Responder 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.

  • Have 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) for larger fire equipment to access.

If you lack any of these, work with your neighborhood and local fire authority to improve accessibility.

Structure Placement

Position of home. If your structures are located on slopes greater than 10 degrees, you must double the recommended management distances. Heat moves up, which results in fires on a slope to pre-heat fuel and move more quickly than on flat surfaces. If your structures are located on a slope, this will result in greater fire severities, and probability of ignition. The adjustment factor for vegetation management depends largely on the slope:

            Under 10 degrees: Use Recommended Values

            10 to 20 degrees: Double Recommended Values

            Over 20 degrees: Triple Recommended Values

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.

Decorative Features such as fencing, firewood and gazebos should be considered in laying out your landscape. As with other fuels, these are combustible materials which only serve to add heat and embers during wildfires. Use appropriate clearance or modify positioning for these features to reduce the threat from burning embers.

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