4 Miscellaneous Circular 19, U. S. Dept. of Agriculture. 
intermountain region about 4,500,000 acres are covered with lodge- 
pole pine and 2,000,000 with aspen. This seems to indicate that 
about one-third of the area has been burned over at some time. 
Without question these forests are very inflammable, and tremendous 
conflagrations will develop in them if fires are given a chance to 
start. This inflammability is not a condition of the past, but exists 
now. 
ae 
wan 
@ 
PER GENT OF 
FOREST FIRES IN THE. 
INTERMOUNTAIN REGION 
HAT Occur IN DIFFERENT 
PARTS OF THE REGION 
Rig. 2. 
Not long ago, on the Teton National Forest in western Wyoming, 
rangers, who were burning brush after a foot of snow had come on 
the ground, found that the fire would run in the dry duff and litter 
under the snow, and that, if it reached some distant dry stump, would 
generate enough heat to send up a column of smoke and stedm over 
the area of the fire. One can readily imagine what would happen 
in a country like this in the heat of midsummer. 
