Defensible Space for Wildfire Protection

Defensible space is the area around a home or other structure where flammable vegetation is modified and maintained to slow the spread of wildfire. Defensible space also creates a safe zone for firefighters to work and reduces the chance of a structure fire moving to the surrounding forest and other homes.

Importance of Defensible Space

Wildfires are a natural part of Colorado’s forest ecosystems. More than 80% of forested lands within Summit County are comprised of lodgepole pine, a highly flammable species that relies on disturbance such as wildfire for regeneration. Because our neighborhoods are surrounded by forests, we must employ proactive management strategies to reduce the potential impacts of wildfire. Creating defensible space around homes is a critical aspect of protecting mountain communities.

Every home in Summit County should have defensible space.

Diagram of defensible space zones.

Creating Defensible Space

To create defensible space around your residence or business, divide your property into zones and then reduce or eliminate vegetation in each zone according to proven wildfire mitigation strategies.

Zone 1

Zone 1 is referred to as the home ignition zone. It extends 15-30 feet from the edge of a home or structure. The first 5 feet surrounding a structure should be comprised of noncombustible surfaces to prevent direct flame contact from igniting the structure. Wildfire mitigation experts recommend removing all flammable vegetation in Zone 1.

Fire-resistant plants and irrigated gardens are acceptable in this zone. Keep grasses short and manageable. If you want to keep one or two trees inside zone 1 for shade or privacy, contact a wildfire mitigation specialist. The location, slope, health and tree species must be considered.

Zone 2

Zone 2 is the area 30-100 feet from the edge of a structure. A major focus in Zone 2 is to break up fuel continuity to inhibit the spread of a fire. This should be done vertically and horizontally: Reduce opportunities for fire to travel across your property horizontally by creating space between trees and shrubs; reduce opportunities for fires to travel horizontally between the ground and tree branches. Wildfire mitigation experts recommend that you remove tree limbs within 8 feet from the ground or 1/3 the height of the tree. Trees should be spaced so that the crown of any tree is 10 feet from other trees. This will reduce the risk of active crown fires.

Zone 3

Zone 3 is the area greater than 100 feet from the edge of a structure. Wildfire mitigation experts recommend that a forest health plan be initiated for this zone. Residents should remove dead and diseased vegetation, limb trees where necessary and create fuel breaks.

Source: Colorado State Forest Service


Summit County provides resources to help residents create defensible space and pursue other wildfire-mitigation strategies:
  • The Summit County Chipping Program provides free chipping and slash removal for residents and property owners who create defensible space.
  • Summit County offers Wildfire Mitigation Grants to eligible homeowner groups who conduct hazardous fuels reduction and other projects to protect homes from wildfire.

Additional Information

For more information on defensible space, call (970) 668-4140.
Colorado State University, U.S. Department of Agriculture and Summit County cooperating. Extension programs available to all without discrimination.