   Creating a Fire Resistive Landscape - July 13, 2005 Jeff Schalau, County Director, Associate Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County Just like drought, fire is a part Arizona’s natural environment. Don’t simply tell yourself that it won’t happen to you – be prepared for wildfire by combining fire-resistive landscaping with fire-resistant home construction and defensible space around your home and property. By applying these concepts, you can significantly reduce the risk of losses from wildfire and make the area safer for firefighters. Fire-resistive landscape plants are essential when reducing wildfire risk. There is no plant that will not burn given enough heat and the proper environmental conditions. Moisture content, percent volatile oils, amount of dead material, and size/height are some factors that are considered. Conifers tend to be more flammable due to the oil and pitch content while deciduous plants tend to be less flammable due to higher moisture content and less fuel during dormancy. Woody plants pose the greatest fire risk in the landscape. They burn much hotter, can carry the fire to structures, and, once ignited, can produce firebrands increasing the fire's rate of spread. Many woody plants carry their foliage to the ground. Trees and shrubs that have dead branches and leaves at or close to ground level create fuel ladders that can carry a fire from the ground into the canopy. In addition, trees and shrubs that are growing in a continuous stand facilitate spread from one plant to the next. Given these factors, you should disrupt the fuel ladder by pruning plants up off the ground and removing dead wood (using proper pruning techniques of course) and isolate trees and large shrubs from their neighbors to disrupt the fuel continuity in the crowns. The purpose of defensible space around your home is to slow the rate of wildfire spread and reduce flame length near the structure. Defensible space also decreases the likelihood that a fire will ignite your home while firefighters are traveling to the fire and allows a greater margin of safety for firefighters that are fighting a fire near your home. Defensible space is often described using numbered zones. Zone 1 is the area within 15 feet of any structure in which any flammable material is removed. The 15-foot distance is measured from the outside edge of the home's eaves, decks, garages, storage buildings, barns, or other structures. This is done through pruning, mowing, or completely removing flammable vegetation and other materials. Be sure to use proper pruning techniques when partially removing woody materials. Zone 2 is an area of fuel reduction. It is a transitional area between Zones 1 and the surrounding native plant community. Typically, Zone 2 defensible space should extend at least 75 to 125 feet from the structure. This varies according to slope with the shorter distances being used for level ground and increasing with the steepness of the slope. Within this zone, the continuity and arrangement of vegetation is modified. Remove stressed, diseased, dead or dying trees and shrubs. Thin and prune the remaining larger trees and shrubs. Be sure to extend thinning along either side of your driveway all the way to your main access road. These actions help eliminate the continuous fuel surrounding a structure while enhancing home site safety and make it easier for fire fighters to access your property. Zone 3 is the area beyond Zone 2, which extends outward to your property boundaries. Zone 3 is of no particular size and is not considered defensible space. However, if there is something particularly flammable or otherwise hazardous, it may be wise to take steps to reduce the hazard. There is much to know and learn about fire resistive landscaping and this column barely scratches the surface. Yavapai County Cooperative Extension also has Gene Twaronite, Defensible Space Educator, available to assist you and your community in creating and maintaining defensible space around your home and property. Gene also works in collaboration with local fire departments and land management agencies. If you would like Gene to present an educational program in your community, you can contact him at 928-445-6590 ext. 231 or e-mail: twaronit@cals.arizona.edu. In addition, you can find several publications related to defensible space and fire resistive landscaping on our web site at: cals.arizona.edu/yavapai/anr/defspace/. The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at mgardener@verdeonline.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://ag.arizona.edu/yavapai/anr/hort/byg/. |