The spacing between grass, shrubs, and trees is crucial to reduce the spread of wildfires. The amount of 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 treetops 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. 3 x 5 = 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.
The information contained on this page is derived from several print and online sources:
University of California Publication 8228. Home Landscaping for Fire. 2007. University of California, Davis.