sunlight which the tamaracks are making
use of.

During the many years that have passed since the fire swept this region,
decaying vegetation has been slowly accumulating and forming humus
again. Now at last the seeds of the spruce find the soil rich enough
again to sprout and grow. Here and there are thrifty young trees which
will in a few years grow up and choke out the tamarack. Thus the
tamarack, though of so little value itself, has done a great work in
preparing the soil for a new growth of the valuable spruce.

Upon the drier slopes of the Western mountains shrubs, such as the
manzanita and chaparral, spring up and cover the surface after a forest
fire. Nature does not seem to want the surface left bare and usually has
something at hand, even though it be nothing better than brush, with
which to clothe it again. As the years pass humus begins to collect upon
the ground and finally restores it to much the same condition it had
before the fire. Now, if by any means seeds can reach such places,
scattering trees will first spring up in favored spots and, after a
time, the trees will become thick enough and large enough to shade the
ground and the brush will be killed out.

[Illustration: _American Forestry_
The work of the water where the forest has been cut away.]

The cutting of the forests, especially from the steeper mountain slopes,
has in many parts of the world changed water, one of Nature's most
valuable gifts, into an agent of destruction. Throughout the Eastern and
Southern states the floods are higher in spring and lower in summer than
they used to be, because of the removal of so large a part of the
forests that once covered this whole region.

In the West it is even more necessary that the forest cover be disturbed
as little as possible. One reason is that the greater part of the
forests are found upon the lofty mountains in which the streams rise. If
we deforest these steep slopes, water is going to injure them much more
than it would the gentler slopes of the lower lands, if they had been
deforested. Another reason is that since little rain falls in the summer
in this region, we must do nothing to lessen the summer flow of the
streams, which is so much needed for irrigation.

[Illustration: _American Forestry Association_
This beautiful valley in the Southern Appalachian Mountains has been
ruined by the floods due to cutting off of the forests upon the
headwaters of the river.]

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