Forest fires are started by either natural causes or by humans. The United States Natural Parks Department which is part of the Department of the Interior says about 10% of forest fires or wildfires are started by natural causes such as lightening and lava. There are two kinds of lightening: cold and hot. The lightening-ignited fires are frequently caused by “unusually long-lasting lightning bolts” of the hot variety.
About 90% of wildfires are caused by humans who carelessly toss lighted cigarettes, abandon campfires, burn debris, or intentionally start a fire (arson). Some fires are purposely set to help forest management. These fires are called a controlled or prescribed burn.
