Wildfires: Homes Fuel The Fires More Than Forests

New research shows a major factor is whether homes are fireproofed -- not just yours, but those of your neighbors as well.

"There is actually more flammable material in a house per square yard than in a forest," said Michael Ghil, UCLA distinguished professor of climate dynamics and geosciences and co-author of the research, which will be published in the Sept. 4 print edition of Proceedings of the National Academy of Sciences.

"It makes a tremendous difference whether you fireproof your home or not," Ghil said. "Neighborhoods where homes are fireproofed suffer significantly less damage than neighborhoods where they are not."

"Our study shows that fireproofing of homes is important not only for the houses, but also for the forest," said Ghil, who is a member of the Institute of the Environment and the Institute of Geophysics and Planetary Physics at UCLA, with a joint appointment in geosciences at France's Ecole Normale Supérieure. "We looked systematically for the first time at both the dwellings and at the forest. When you fireproof houses, not only do you help preserve those houses, but you also help limit the spread of fires to a much smaller area."

Ghil and his co-authors modeled the spread of fires and studied data from forest ecosystems in Colorado, Montana, New Mexico, Utah, Washington and Wisconsin. They addressed both the houses and the trees in a unified way for the first time.

"Many people seem to have a fatalistic attitude and don't understand that it really matters whether you fireproof your home, and whether your neighbors do," Ghil said. "The spread of forest fires is not just an act of God. Fireproofing houses can make an enormous difference in whether a fire sweeps through a community or not." As the density of non-fireproofed houses increases, the chances of the neighborhoods burning increase dramatically, Ghil said.

Many regions in the United States have experienced a long period of severe drought, which increases the flammability of the forest, Ghil noted. Other factors in the spread of forest fires include vegetation (if it is drier, the chances of a fire spreading increase) and wind intensity and direction.

Homes built in the hills, near natural vegetation or in other parts of what is commonly called the "wildland-urban interface" are very common in the United States and account for well over one-third of all housing.

Co-authors of the research are Vassilis Spyratos, a graduate student at France's Ecole Normale Supérieure, and researcher Patrick Bourgeron, a fellow at the Institute of Arctic and Alpine Research at the University of Colorado in Boulder.