the other hand they may
be seen helping each other in their community growth by protecting
each other from windfall and by contributing to the fertility of the
forest soil in dropping their leaves and shading the ground so that
these fallen leaves may decompose readily.

[Illustration: FIG. 154.--Trees also Grow in Communities.]

4. Enemies of trees: An old stump or tree may be seen crumbling away
under the influence of fungi and here the children may be shown the
effects of tree diseases both as destroyers of life and as
up-builders, because fungi turn to dust the living trees and build
up others by furnishing them with the decomposed wood matter.

Insects too, may be invading the old dead tree, and something of
their nature, habits and influences may be gone into. They may be
shown as wood borers, leaf eaters, or sap suckers, all injurious to
the tree. On the other hand they may be shown as seed disseminators
and as parasites on other injurious insects; all benefactors.

Forest fires as an enemy of trees might be touched upon by noting
how easily the leaves may be ignited and a surface fire started when
the season is dry. Top and ground fires emanating from surface fires
can then be readily explained.

[Illustration: FIG. 155.--Trees Blend Together to Form a Beautiful
Composition.]

5. Expression: The pupils have by this time been taught to feel the
beautiful, to observe carefully and to reason intelligently and they
may now be trained to express themselves properly. This may be
accomplished by asking them to remember their observations and to
write about them in the classroom. The lesson may be supplemented
with effective reading about trees and forests. Interesting reading
matter of this sort can be found in abundance in children's readers,
in special books on the subject and in Arbor Day Manuals published
by the various State Education Departments.

6. Preparation: In order to save time looking for objects of interest
and for the purpose of correlating the various observations so that
all will follow in orderly sequence, it is well for the teacher or
leader to go over the ground beforehand and note the special
features of interest. The various topics can then be given some
thought and a brief synopsis can be drawn up to serve as a
memorandum and guide on the trip.

It is also wel