Defensible space is the area around a structure where fuels have been reduced to decrease the threat of wildfire. Nationally, two factors have emerged as the primary determinants of a structure’s ability to survive a wildfire: the type of roofing material used and the quality of defensible space around it. Although each situation is different and a customized plan for your site depends on a variety of factors, the 3 zone approach is a commonly accepted practice which provides good defensible space management.
Zone 1 extends from the drip line of the roof or any attached structure (deck, etc.) out 15 feet from the structure. All flammable vegetation should be removed from this area. Zone 2 is the transition area between Zone 1 and 3. This reduced fuel zone extends to a minimum of 100 feet from the structure. Stressed, diseased, dead or dying trees and shrubs should be removed. The remaining trees should be thinned so that there is at least 10 feet between the crowns and be pruned to a height of 10 feet above the ground or 1/2 their height (whichever is the least). Grasses and weeds should be maintained to a maximum height of 6 inches. Zone 3 extends to the property line. Fuels treatment is not necessary in this area, but will enhance wildfire safety. By creating a defensible space around your home, you are giving firefighters room to work.