Don’t Play With Fire: Create Defensible Space
Creating defensible space helps firefighters protect your home from wildfires. (Click on the image to enlarge it.)
Maintain a 100-foot defensible space around structures:
- 10-foot ignition zone
- 30-foot clean zone (or to property line)
- 70-foot reduced fuel zone (or to property line)
Tips for creating a defensible space:
- Clear ALL flammable vegetation from within 10 feet of propane tanks
- Use hard surfaces (concrete, stone, asphalt, brick, etc.) in your landscaping
- Trim tree branches within 10 feet of a chimney or stovepipe
- Remove all needles and leaves from beneath decks and within two feet of any structure; in open areas, restrict needles and leaves to a depth of 2 inches to prevent erosion
- Trim grass to 4 inches in height except where soil erosion is an issue, where 18 inches is allowed
- Eliminate ladder fuels that allow flames to climb upward (such as tall shrubs, small trees, low-hanging branches) in addition to other debris beneath trees
- Space trees 20 to 30 feet apart, officials recommend
Fire safety is a community effort: When homes are close together, creating defensible space means neighbor helping neighbor. (Click on the image to enlarge it.)
Ideally, grass should not exceed four inches in height. In situations where these fuels are isolated from other fuels or where necessary to stabilize soil, grasses and similar vegetation may reach a height of 18 inches.
Horizontal Clearance for Shrubs and Trees
Clearance between shrubs should be 4 to 40 feet depending on the slope of the land and size and type of vegetation.
Vertical Clearance for Shrubs and Trees
Low branches create 'ladders' from the ground fuels to the trees. To determine the proper vertical clearance between shrubs and the lowest branches of trees, use this formula:
3x height of shrub = minimum vertical clearance
For example, if a shrub is 4 feet tall, the minimum vertical clearance between the top of the shrub and lowest tree branch is 12 feet.
Note: A grouping of vegetation may be treated as a single plant if the foliage of the grouping does not exceed 10 feet in width. For example, three individual manzanita plants growing in a cluster with a total foliage width of 8 feet can be
'grouped' and considered as one plant.
Protecting Your Home From Fire
Protecting Your Home From Fire (Click on the image to view larger [PDF] image.)
Continuous Tree Canopy
Prune lower branches of trees to a height of six to 15 feet from the top of the vegetation below (or the lower 1/3 of branches for small trees). Properties with greater fire potential, such as steeper slopes, or more severe fire danger will require pruning heights in the upper end of this range.
Remove all ground fuels greater than four inches in height. Single specimens of trees or other vegetation may be kept if they are well-spaced, well-pruned and create an overall condition that avoids the spread of fire to other vegetation or to structures.
Any questions regarding requirements for a specific property should be addressed to a local fire official.
Download a Defensible Space illustration:
Working together, we can help prevent catastrophic wildfires.