The Morning Report
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Monday, Oct. 5, 2009 | Your attention to Fire Prevention (Keegan Kyle, 9/24/09) is commendable. Wildfire property losses have proven to be far lower when homeowners take responsibility — to build, retrofit, and maintain houses to current building codes for structures in fire-prone areas, and to maintain landscaping and thin vegetation in their “defensible space.”
Yet often the entire focus has been on brush management — by homeowners, fire departments, and communities. It is only part of the fire prevention program, and often the least important when the wildfire arrives. Wildfire damage assessments have shown that most structures ignite from embers landing in or on combustible materials of a house (entering the attic through unprotected vents, or on a wood roof), or from radiation created by burning vegetation or other combustible materials adjacent to the house. An ember may land in an un-pruned juniper shrub and ignite it; if the juniper is close to the wood siding or under the wood eaves or next to a single-pane window, the radiation heat of the burning shrub is likely to ignite the structure. As most embers are generated from burning houses, fan palms, and vegetation carried long distance by high winds, firefighters agree that structures are not “safer” if more than 100 feet of defensible space is maintained.
The recent emphasis on fuel reduction risks excessive removal of native chaparral and coastal sage scrub; over-pruning and mortality of shrubs; erosion and stormwater runoff; invasive and flammable weeds; and loss of many native animals. Misguided codes prohibit native plants in landscaping, yet many natives are often more drought-tolerant, grow slower, and retain more moisture in hot, dry Santa Ana winds. When codes require excessive tree pruning and tree removal, urban tree owners and communities lose out on aesthetic, shade, energy-saving, environmental, and economic values of trees. These measures miss the mark, as recent wildfire damage assessments have shown, again and again, that homes survive when maintained to remove places for embers to ignite on or in the structure.