Wildfire is among the most common forest disturbances, affecting the structure, composition, and functions of many ecosystems. The complex role that wildfire plays in shaping forests has been described in terms of vegetation responses, which are characterized as dependent on, sensitive to, independent of, or influenced by fire (Myers 2006). Fire is essential in areas where species have evolved to withstand burning and facilitate the spread of combustion, such as the Pinus spp. found in the Coastal Plain of the Southern United States. Notable fire-dependent ecosystems include many boreal, temperate, and tropical coniferous forests, eucalyptus forests, most vegetation assemblages in Mediterranean-type climates, some forests dominated by oaks (Quercus spp.), grasslands, savannas, and marshes, and palm forests. At the other extreme, fire is largely absent where cold, wet, or dry conditions prevail (such as tundra landscapes, some rain forests, and deserts). Fire-sensitive ecosystems that have evolved without fire as a significant process have become more vulnerable to human activities such as stand fragmentation, alteration of fuels, and increased ignitions. Fire-influenced ecosystems generally are adjacent to areas where fire-dependent vegetation facilitates ignition and spreading of wildfires.