Patrick Bourgeron worked with Michael Ghil (UCLA) and Vassilis Spyratos (Ecole Normale Superieure) to model the spread of fires in forest ecosystems in Colorado, Montana, Utah, New Mexico, Washington and Wisconsin. Their study is the first to systematically look at both houses and trees in forest fire scenarios. They found that the size of fires is directly linked with the density and flammability of houses built in the so-called "wildland-urban interface." Since houses are much more flammable per square yard than forests, homes that erupt in flames can propel forest fires to a critical intensity threshold much more quickly. Thus, fireproofing homes not only preserves structures, but limits the size of forest fires. The study was published in the Sept. 4 print edition of the Proceedings of the National Academy of Sciences.