This happens because the moisture in the tree evaporates and the heat in the tree causes it to explode into flames. Also, fire brands and ash get blown up into the sky where they land on the forest floor and cause another fire. These are different ways a fire can spread quickly through the forest besides strong winds, lots of fuel, and heat. Many times if there is a fire they will send in Hot Shots or Fire Jumpers to try to stop it from going into populated cities, towns, or destroying thousands of acres of wilderness. Usually Hot Shots, fire jumpers, and firemen are not always the ones to put out a fire.
Nature is the best source for putting out fires.
Snow, rain, loss of fuel for the fire, and more, can put out a fire better and faster than Hot Shots or retardent. Many people think fire is a bad thing. Yes, sometimes it can be. But fire is a way for nature to regenerate and have rich soil for the next generation of growth. Soild burning fire that can be extinguished by water.