Which of the following is NOT a main cause of forest fires?

Heavy rainfall is not considered a main cause of forest fires. In fact, it often acts as a mitigating factor. When there is significant rainfall, the moisture content in the soil and vegetation increases, making it more difficult for fires to ignite and spread. This moisture reduces the likelihood of fire as it saturates the ground and any combustible materials, providing a natural defense against potential ignition sources such as lightning strikes or human activity.

On the other hand, lightning strikes, human activity, and equipment use are all known catalysts for wildfires. Lightning can ignite dry vegetation during thunderstorms, while human activity—including campfires, discarded cigarettes, and arson—contributes significantly to the number of wildfires that occur. Equipment use can also lead to fires through sparks generated by machinery or tools coming into contact with dry materials.