   Addressing Your Wildfire Risk - May 3, 2000 Jeff Schalau, County Director, Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County If your home and yard are adjacent to natural open space, you may already have interactions with wildlife, insects, reptiles, and native plants. As we approach the dry months of May and June, you should also consider the possibility (or probability) of wildfire and how this could cause damage to your home or property. This week we will consider your risk factors and discuss some actions that may put you at lower risk if you happen to live in one of these wildland/urban interface areas. Risk factors include fuel and vegetation types, topography, structural materials used in and around your house, accessibility, and water availability. Fuels The density, height, and size of dead or dry plant material can determine the intensity at which they will burn and how a fire will behave. Fine fuels are often needed to start a fire. Fine fuels can be any combination of grasses, twigs, dry leaves, or trash. These can create a ground fire. Ground fires are beneficial in natural settings because they cycle nutrients, decrease fine fuels and decadent vegetation, and reduce risks of more intense fires. If ladder fuels are present (woody material linking the ground fuels to the tree or shrub canopy), then a ground fire can turn into a crown fire. A crown fire is intense enough to instantly dry and consume live, green material. Crown fires move fast and furious often creating their own intensely drying wind. This is the sort of fire behavior that occurred in Oakland, California in 1991. As you can probably guess, you do not want a crown fire to occur next to your neighborhood. Topography Fire travels like water only in reverse. Where water runs rapidly downhill, fire runs rapidly uphill. Where water concentrates into canyon bottoms, fire travels upward from the canyon bottom in all directions. These put homes at great risk when they are on a slope above a densely wooded or shrubby area. Prevailing wind direction can also add risk. Generally, our winds predominantly blow from the southwest. Consider this when assessing your risk also. Structural Materials Cedar shake roofs, wood siding, and wood fences can dramatically increase risk. Tile roofs are considered safest, with metal and asphalt being moderately safe. The most effective way to protect a structure is to create defensible space. This is done by removing fuels, creating spaces where firefighters can protect your home, and having a reliable emergency water supply. Firescaping Native fuels can be managed to reduce risk of property damage. To ensure maximum protection, no combustible fuels should be within 5 to 10 feet of the house. Reserve this area for succulent ground covers, gravel, walkways, or lawns. Out to 30 feet from the house, trees should be well-spaced so that crowns do not overlap, shrubs should be high moisture content and low growing, lawn or irrigated pasture is also acceptable. Beyond this, plants should have dead wood removed and fuel ladders should be eliminated. Fire resistant plants can also be used in conjunction with the concepts listed above. In a perfect world, these plants should all be irrigated to reduce risk. Cactus and succulents are excellent low water use plants for firescaping. Conversely, coniferous trees and shrubs (pine, fir, spruce, cypress, juniper) tend to be highly flammable under hot dry conditions. Eucalyptus, ornamental grasses, and acacias are also considered high risk. If you think you live in a high risk area, then you should take steps to reduce your risk factors. The suggestions presented here present a simple overview of fir escaping and risk reduction. To get more information, buy or borrow a copy of California Wildfire Landscaping by Maureen Gilder (1994, Taylor Publishing). The University of Arizona Cooperative Extension has publications and information on landscaping and natural resources. Visit our web site at http://ag.arizona.edu/yavapai/. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at mgardener@kachina.net and be sure to include your address and phone number. |