"Home ignitability" factors and are the principal causes of home losses during I-zone fires. These factors include the design and materials used for home construction, such as wooden versus metal roofs, and the amount and kind of vegetation located within approximately 200 feet of the home. When homes and their landscapes are properly designed, constructed, and maintained to reduce ignitability factors, then this greatly increases their chance of surviving wildfires.

Cohen's photographs of Los Alamos reveal that when the wildfire entered and burned through the town it was not a high-intensity crown fire, but instead, was a low-intensity surface fire. [see photos on reverse page] Homes with high ignitability factors, such as heavy pine needle accumulations on their rooftops and in their yards, and firewood piles next to houses, suffered complete fire destruction, while surrounding vegetation was moderately scorched or unburned. With just a couple exceptions, tree canopies that were consumed by fire were ignited from burning houses. In one case, a home was completely destroyed while a nearby wooden fence suffered only minor damage. Once homes with high ignitability burned, they set in motion a "chain reaction" effect of fire spreading from structure-to-structure while a low-intensity surface fire burned through the surrounding vegetation.

The Los Alamos fire conforms with Cohen's SIAM and reveals that vegetation management for reducing home fire losses need only occur within a few tens of meters from a home, not hundreds of meters or more away from homes. Fuels reduction treatments carried out beyond 200 feet from structures are both inefficient and ineffective for home protection goals: inefficient because wildland fuel reduction for several hundred meters or more around homes is greater than necessary for reducing ignitions from flames; ineffective because it does not sufficiently reduce ignitions from embers that may travel from several kilometers away to set flammable or unmaintained rooftops on fire.

As Congress and federal land management agencies consider various fuels reduction strategies on public lands, ostensibly to protect rural communities from wildfires, the Los Alamos fire and Cohen's research reveal that the prime area of concern in I-zone fires is located predominantly privately-owned land. Ultimately, it is the main right and responsibility of homeowners to manage the structures and vegetation on their own private lands to reduce home ignitability--it should not be the burden of taxpayers throughout the country to pay the economic costs and environmental impacts of extensive fuels reduction projects on public lands.