What are the principal causes of forest fires in the different sections?

In the Lake States and New England, fires are mostly man-caused; careless smokers head the list. In the Eastern and Southern States, also, they are mostly man-caused; careless brush and field burners and (in the South) intentional fire setters head the list. In the Rocky Mountain area, more than 70 percent are started by lightning; the others result from carelessness while smoking. In the Northwest, about half the fires start with lightning; careless smokers and campers (who abandon campfires) are serious offenders. In California, lightning starts about 23 percent, careless smokers and campers most of the others.