I created a new world to try to find any bugs with the game and I noticed that right next to my spawn there was a small lava lake. Then I noticed that it began burning down a tree. Then that fire spread and caught on to the next tree. And so on and soon the whole forest was ablaze and burning down AT my spawn point.
The attachment shows the lava catching fire to a nearby tree, which would, in a few minutes, spread to the entire forest.