   Firewise Landscaping - February 20, 2002 Jeff Schalau, County Director, Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County Many of our native plants tolerate fire and many even rely on fire for renewal and/or propagation. This tells us something about where we live: fires are part of our natural environment. Catastrophic fires, such as the Cerro Grande fire that charred Los Alamos, New Mexico in May 2000, could easily occur here. Given our current drought situation, frequency of dry lightning before the monsoon, and other risk factors, I encourage you to take some steps to reduce risk around your home and landscape to decrease the potential for loss of life and property in the event of a wildland fire. I know that most people like where they live, but consider the location of your home if you are still shopping for a location. A level site is safer than a sloped site and narrow canyons act as chimneys that can channel fire greatly increasing the rate of spread. Other considerations that can reduce risk are: proximity to a fire station, access to fire hydrants, access to your property, and clearly marked street numbers. Many Fire Departments will come out to neighborhoods and inform homeowners of things they can do to increase accessibility and reduce potential risks. Home construction can also greatly reduce fire risk. Untreated, wood shake roofs are the number one cause of home losses from wildland fire. Roofs should be non-flammable (i.e. tile or asphalt/fiberglass composition). Likewise, wood siding also can increase risk. Eaves should be boxed in, chimneys equipped with spark arrestors, and windows of tempered safety glass. Rain gutters should be cleaned regularly to prevent fuel accumulation. Never pile firewood near the home or under a wood deck. Wood decks themselves are particularly risky. Consider using pavers, flagstone, or concrete where possible. For more information, consult the Firewise web site at firewise.org. Once you've done as much as you can reasonably accomplish with location and structural risk factors, you can modify your landscape. This is the area where most people have the greatest potential to reduce wildfire risk. This also creates an opportunity to beautify your surroundings. 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 to consider. 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. Colorado State University has some excellent resources available on Firewise Landscaping on their web site: www.ext.colostate.edu/pubs/natres/pubnatr.html. I am also working on a firewise plant list for Yavapai County. Rock has its place in the landscape. However, I am not a big fan of large areas of gravel. It is, however, fire resistant. I prefer natural soil and native grasses/perennials when working with larger areas of "bare" ground. These herbaceous plants may burn, but will not create a hot, intense fire. Rather, it will be a quick burn with relatively little heat generated. To further reduce risk, dead herbaceous plant materials can be gathered up or mowed at the end of the growing season. Cactus is also a fire resistant plant. Prickly pear is easy to propagate, drought tolerant, and provides cover for wildlife. 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. A good rule of thumb is to prune high-risk trees 10 feet above ground. However, to maintain tree health, no more than 30% of the live crown should be removed at any one time. Trees should not be planted next to structures and existing trees should be pruned to reduce risk. As you scan your home and landscape, learn to recognize risk factors and reduce or eliminate them. It may save your home…or your life. Next week, I will expand on reducing fire risk through creation of defensible space around your home. 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 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/. |