Our forests are exposed to destruction by many enemies, the worst
of which is fire. From 8,000,000 to 12,000,000 acres of forest
lands annually are burned over by destructive fires. These fires
are started in many different ways. They may be caused by sparks
or hot ashes from a locomotive. Lightning strikes in many forests
every summer, particularly those of the Western States, and
ignites many trees. In the South people sometimes set fires in
order to improve the grazing. Settlers and farmers who are
clearing land often start big brush fires that get out of
their control. Campers, tourists, hunters, and fishermen are
responsible for many forest fires by neglecting to extinguish
their campfires. Sparks from logging engines also cause fires.
Cigar and cigarette stubs and burning matches carelessly thrown
aside start many forest fires. Occasionally fires are also
maliciously set by evil-minded people.

The officers of the National Forests in the West have become
very expert in running down the people who set incendiary fires.
They collect evidence at the scene of the fire, such as pieces of
letters and envelopes, matches, lost handkerchiefs and similar
articles. They hunt for foot tracks and hoof marks. They study
automobile tire tracks. They make plaster of Paris impressions of
these tracks. They follow the tracks--sometimes Indian fashion.
Often there are peculiarities about the tracks which lead to the
detection and punishment of the culprits. A horse may be shod in
an unusual manner; a man may have peculiar hob nails or rubber
heels on his boots or else his footprints may show some
deformity. The forest rangers play the parts of detectives very