Forest Fires in the Intermountain Region. 5 
WHAT CAUSES THE FIRES. 
There is a general belief that forest fires are nearly always started 
by something beyond the power of man to prevent, such as hghtning, 
dry limbs rubbing together in the wind, or broken bottles acting as 
lenses to concentrate the rays of the sun. Nothing could be further 
from the truth. There are only two causes of forest fires in this 
Fic, 3.—Fires started by lightning are unavoidable; those 
started by man are inexcusable. 
region. They are human carelessness and lightning. Of the two, 
human carelessness is responsible for the greater number, as less 
than half of the fires in the intermountain region are caused by 
lightning (fig. 3). Records of the past 15 years show that 47 per 
cent resulted from hghtning, 35 per cent from the carelessness of 
campers, 6 per cent from brush burning in which the fire was al- 
lowed to escape, 5 per cent from locomotive sparks, 4 per cent from 
ee 
