Lightning-caused fires are a natural part of the ecosystem in the Assessment Area. Topography and weather patterns make certain portions of the area particularly prone to lightning strikes. Fires caused by people have a variety of origins including camping, smoking, use of vehicles or equipment, or arson. These fires are more likely in areas that people can access through roads and therefore, the presence of roads is a risk factor for ignition. Once ignited, factors that cause a fire to spread and determine its severity include the amount of fuel near the point of ignition, the structure of the forest at the point of ignition, and weather conditions, such as the strength of the wind and the amount of moisture in the fuels and in the air.
Weather conditions vary widely and are difficult to quantify.
However, the amount of forest fuels can be quantified by estimating the amount and types of woody debris. The forest structure affects the ability of the fire to spread. Once in the canopy, the fire can move quickly from treetop to treetop, establishing a crown fire. The more dense and more even-aged the stand and adjacent stands the more quickly and intensely the fire will burn. Map V-4 .