Creating an Effective Defensible Space

As the number of people living in and adjacent to wildlands grows, the likelihood of homes being threatened by wildfire also grows. A critical factor in determining whether or not a home will survive a wildfire is the type, amount, and maintenance of vegetation surrounding the house. Defensible space, sometimes referred to as "Survivable Space," refers to the area between buildings and an oncoming wildfire where the fuels have been modified enough to reduce wildfire threat and to provide an area where firefighters can safely work to defend the structures. With enough fuel reduction in the defensible space, your home may even be able to survive a wildfire without firefighter assistance.

The first three to fuve feet around structures should be a fuel-free zone. Avoid planting anything in this area or storing any flammable materials. Better yet, fill in this area with something completely non-flammable, such as decorative stone or gravel. Regularly clean the area to keep it free of any fallen leaves, branches, or pine needles.

For the next 30 feet, keep the grass cut short, well watered, and free of accumulated flammable debris. Trees and shrubs in this area should be well spaced and preferably restricted to deciduous species (those with leaves that drop in the fall). Look for potential "fuses" like wooden walkways, fences, and weedy gardens that reach from the woods to your buildings. Break these up with patios or green lawn. Keep flammables such as lumber and firewood piles out of this area. As a final check, take a stroll around this area with an imaginary match in your hand. If you see a place where you would not feel comfortable lighting that match, throwing it down and walking away, you still have some Firewise work to do.

Continue to keep trees and shrubs well spaced in the area 30 to 100 feet around buildings. This is especially important if the area is predominantly evergreens. Thin trees and shrubs so that they are at least 10 feet apart. Prune branches off the remaining trees six to 10 feet up the trunk. This process reduces the "ladder fuels" that would allow a fire to move from the ground to the treetops and from tree to tree, resulting an uncontrollable crown fire.

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