elop into trees. The coniferous
trees do not lend themselves at all to this system of treatment,
and, among the broadleaf trees, the species vary in their ability to
sprout. Some, like the chestnut and poplar, sprout profusely; others
sprout very little.

How forests are protected: Forestry also tries to protect the forests
from many destructive agencies. Wasteful lumbering and fire are the
worst enemies of the forest. Fungi, insects, grazing, wind, snow and
floods are the other enemies.

[Illustration: FIG. 132.--The Result of a Forest Fire. The trees,
lodgepole pine and Englemann spruce, are all dead and down. Photograph
taken in the Colorado National Forest, Colorado.]

By wasteful lumbering is meant that the forest is cut with no regard
for the future and with considerable waste in the utilization of the
product. Conservative lumbering, which is the term used by foresters
to designate the opposite of wasteful lumbering, will be described
more fully later in this study.

Protection from fire is no less important than protection from
wasteful lumbering. Forest fires are very common in this country and
cause incalculable destruction to life and property; see Fig. 132.
From ten to twelve million acres of forest-land are burnt over
annually and the timber destroyed is estimated at fifty millions of
dollars. The history of Forestry abounds in tales of destructive
fires, where thousands of persons have been killed or left
destitute, whole towns wiped out, and millions of dollars in
property destroyed. In most cases, these uncontrollable fires
started from small conflagrations that could readily, with proper
fire-patrol, have been put out.

There are various ways of fighting fires, depending on the character
of the fire,--whether it is a surface fire, burning along the
surface layer of dry leaves and small ground vegetation, a ground
fire, burning below the surface, through the layer of soil and
vegetable matter that generally lines the forest floor, or a top
fire, burning high up in the trees.

When the fire runs along the surface only, the injury extends to the
butts of the trees and to the young seedlings. Such fires can be put
out by throwing dirt or sand over the fire, by beating it, and,
sometimes, by merely raking the leaves away.

Ground fires destroy the vegetable mold whic