The causes of landscape fires are divided into “natural” and “human-caused”:
- Natural: The most common cause is lightning. During thunderstorms (thunderstorm that occur without rainfall, also called dry thunderstorms) cloud-to-ground lightning strikes find deal conditions to ignite dry vegetation cover and expand to large wildfires. In some regions volcanic activities can result in wildfires.
- Arson: Fires caused by deliberate human action, for many reasons.
- Negligence: Fires caused by unintentional human action such as disposal of burning cigarettes, burning of waste, outdoor work (by machinery), hikers, hunters, campfires, children playing with fire, military shooting exercises, sparks from trains, and various other causes such as traffic and industrial accidents.
- Agricultural and pasture burning: Burning of agricultural crop residues on fields and fires set by shepherds to clean pastures from dry vegetation and bush encroachment are the most important causes of uncontrolled wildfires. Very often these fires are not attended and spread to forests, protected areas or settlements.
In many countries the causes of fires cannot be identified easily. Thus, the amount of unknown fire origins is often very high.
