Understanding how wildfires get started is key to reducing the risk of them. Forest fires can start from natural causes, and there is little you can do about them. However, there are also human causes, and these are the ones that we can all do a part in preventing. Lightning Striking the Tree One of the most natural reasons for fires to start is lightning striking a tree. This is usually a dead or diseased tree since there won’t be any moisture in them. However, the lightning can also strike healthy trees and cause problems. This is usually when lightning strikes without any rain or when the water has already absorbed due to the heat. Lightning strikes can’t be stopped.