Forest fires
In forested areas unaffected by man forest fires occur regularly. The usual cause is lightning that starts fires during the warm part of the year and especially in dry years. These fires cause a natural rejuvenation of the forest and increases the species diversity of plants and animals. So forest fires that happen naturally should not be extinguished in national parks.
Large areas have been forested for economic profit, however. Bush and forest fires in the Mediterranean region and California gain large attention not only because of their size but because they occur in densely populated areas with large material investments per square kilometer. We know these fires happen at the end of the local summer when water levels in the bush have sunk to about 11%. Lightning frequency is also greater in higher temperature, so forest fires are more common closer to the equator than in the temperate zone.
Landslides, earthquakes and volcanic eruptions may also cause forest fires.
The marks of a forest fire can be found in the annual growth rings of surviving trees and as coal particles that are embedded in the soil. Our database TRITON contains information on forest fires going very far back in time, which enables us to calculate the future risks of fire and its effects.