Fire is a natural component of forest ecosystems in parts of North America, South America, Europe, Australia, Africa and the Mediterranean region. These fires are usually uncontrolled wildfires in areas of ignitable vegetation but can also be prescribed fires set for vegetation management purposes. Wildfires are commonly characterised based on cause of ignition, physical properties (e.g. propagation rate), fuel material and weather conditions. The four major natural causes of wildfire ignitions are lightning, volcanic eruptions, sparks from rockfalls and spontaneous combustion. Among the most common human-induced sources of wildfires are escaped prescribed fires, arson, unextinguished campfires, trash fires, cigarette, equipment sparks and power line arcs.