nce of prevention is worth a pound of cure." Also the people are being
taught correct forestry practices, such as cutting only ripe trees and
allowing the rest to grow, instead of clearing the land entirely, as was
formerly done so universally.

[Illustration: BALD CYPRESS DRAPED WITH SPANISH "MOSS."

This tree is almost entirely hidden by this "moss," which is really a
flowering plant of the Pineapple family. Range: In swamps and along
rivers from Delaware to Florida, west to Texas, north to Missouri and
southern Indiana. Photograph by G. Clyde Fisher.]

The life history of every tree is interesting; how it breathes by means
of its leaves, just as the animals do by means of gills or lungs; how it
manufactures starch by means of the green matter in the leaves; how the
starch is changed to sugar and other substances which are carried to
other parts of the tree in the sap; how the sap flows upward in the
vessels in the sap-wood and downward in the vessels of the inner bark;
how the entire heart-wood of a tree is dead and the only living part is
the sap-wood and the innermost bark.

One of the first things we shall want to know when we get out into the
woods is the name of the tree that interests us. For this purpose the
books given as references under "Trees" will be useful.

[Illustration: TIMBER WOLVES ON THE TRAIL

Closely related to foxes and dogs. Range: Formerly over most of North
America. Habitat Group in American Museum of Natural History.]

[Illustration: BABY OPOSSUMS RIDING ON THEIR MOTHER'S BACK

For the first few weeks after they are born the mother carries her
babies in her pocket; later they ride on her back holding on by clinging
to her fur with their paws and by wrapping their tails about that of
their mother. Range: Middle and Southern States. From Group in American
Museum of Natural History.]

3. ANIMALS

Mammals

Mammals differ from birds in that they have hair instead of feathers,
and that they are first fed upon milk produced by the mother.
Unfortunately the mammals are usually called simply _animals_, but the
latter is obviously too inclusive a term and should not be used in this
way. There is no reason why the name _mammal_ should not be commonly
used, just as _birds_, _reptiles_, _amphibians_, and _fishes_ are used
for the other groups of backboned animals.

[Illustration: NEW YORK WEASEL IN SUMMER PELAGE]

[Illustration: OTTER WITH ITS FAVORITE FOOD

The Otter belongs to the We