[Ill.u.s.tration: BLACK SUGAR MAPLE

The sap of this tree, as well as the more common Sugar Maple, is the source of maple sugar. Range: Eastern United States and southeastern Canada.]

The turpentine industry is the chief one in parts of the South where the Long-leaved Pine thrives. The United States produces more turpentine and rosin than any other country in the world. The turpentine is used in paints and in various arts. The rosin is used in varnish, laundry soap, etc. These two products come from the sap or "gum" of the pine tree. The sap is secured by tapping or "boxing" the tree, and then keeping the cut ducts of the sap-wood open by "chipping" or "pulling," that is, by putting a new "streak" on the tree. This has to be done once a week from March 1 to November 1. The sap used to be collected in a "box" or deep notch cut in the base of the tree, but the modern method is to have it run into cups made of zinc or of burned clay similar to flower-pots. The sap is taken to a turpentine still where it is heated over a furnace.

This drives off the turpentine or "spirits" as steam or vapor, which is condensed to liquid again by pa.s.sing through the worm of the still surrounded by cold water. The rosin or resin is left behind.

[Ill.u.s.tration: COMMON FALL MUSHROOM

An excellent article of food growing commonly in old pasture fields.

Range: Temperate and tropical regions all over the world. Photograph by G. Clyde Fisher.]

The Sugar Maple grows from Florida and Texas northward to Manitoba and Quebec, but it is only in the northern part of its range that the maple sugar industry thrives. This delicious food is one of the many that we learned to utilize from the Indians. The sap is obtained by tapping the tree in the spring before the leaves come out, the best weather for the flow of sap being that when it freezes at night and thaws in the daytime. The sap is boiled down; that is, the water is driven off and the sugar remains. It takes about three gallons, or a little more, of sap to make a pound of maple sugar. Three to four pounds of sugar is an average yield for one tree in a season. Much of the sap, however, is not boiled down into sugar, but the boiling is stopped while it is in the form of syrup. If you have ever eaten buckwheat cakes with real maple syrup you will always esteem the Sugar Maple tree.

The forests perform extremely valuable services for mankind entirely apart from the products they yield.

First, they prevent erosion, or the washing away of soil by the water that falls as rain. After the trees have been cut away, very often, especially upon hillsides, the most productive soil is washed away, usually clear off of the original owner's farm, and deposited in the flood-plains or bottoms of creeks and rivers or in river deltas--in places where it cannot be utilized to any great extent. Thus erosion causes a tremendous loss to farmers, and it is chiefly due to the thoughtlessness of the American people in destroying the forests.

Second, and chiefly related to this, is the fact that the floods upon our rivers, which every year take such heavy toll in property and in human life, are due to the cutting away of the forests. This allows the water from rain and melting snow to reach the streams at times faster than it can be carried off, and so we have a flood. The forest floor, with its undergrowth and humus, in those localities where the forests still exist about the headwaters of our rivers, acts like a huge layer of blotting paper which holds the water back and allows it to escape to the streams slowly, and so floods are avoided.

Third, and related to the above, is the fact that the water supply of our cities would be more constant if the forests had not been cut away.

In these cases the summer droughts make much greater the danger from water-borne diseases.

[Ill.u.s.tration: WESTERN YELLOW PINE

A magnificent tree which furnishes valuable timber. Range: Hills and mountains of western United States. Photograph by Albert E. Butler.]

[Ill.u.s.tration: ROADS THROUGH THE ASPENS

Range: Northern United States and Canada, south in the Rocky Mountains to Mexico. Photograph by Albert E. Butler.]

It is only in recent years that the American people have begun to realize the necessity of the conservation of our forests, and in many sections much has been done to redeem the criminal thoughtlessness in destroying our forests and to restore those devastated by forest fires.

Reforestation operations have accomplished a great deal, and the organization to prevent forest fires emphasizes the old adage that "an ounce 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.

[Ill.u.s.tration: 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.

[Ill.u.s.tration: 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.]

[Ill.u.s.tration: 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.

[Ill.u.s.tration: NEW YORK WEASEL IN SUMMER PELAGE]

[Ill.u.s.tration: OTTER WITH ITS FAVORITE FOOD

The Otter belongs to the Weasel family, and feeds almost entirely upon fish. Range: This and related varieties over Northern and Eastern North America. From Group in American Museum of Natural History.]

In the United States the lowest or most primitive mammal is the Opossum.

The baby Opossums--from six to a dozen of them--are born when very small and undeveloped and are immediately placed by the mother in an external pouch, where they continue to grow until they are too large to get into their mother's pocket; then they frequently ride upon their mother's back, clinging to her fur with their finger-like toes and wrapping their tails about their mother's tail. The Opossum is the only animal in this country the young of which are carried around in the mother's pocket, and the only one which has a prehensile tail; that is, one used for coiling around and clinging to branches, and the like. Its food is various, consisting of both animal and plant material--insects, young birds, pawpaws, persimmons, etc. In the food devoured the Opossum probably does more good than harm.

[Ill.u.s.tration: NEW YORK WEASEL IN WINTER

A blood-thirsty cousin of the Otter and the Mink. Range: This and related species found all over United States and Canada. Group in American Museum of Natural History.]

[Ill.u.s.tration: RACc.o.o.n AT ENTRANCE TO ITS DEN IN A HOLLOW TREE

A near relative of the bears. Note the black face-mark and the ringed tail. Range: This or a related variety occurs in all parts of United States. Photograph from American Museum of Natural History.]

In their food habits many mammals are decidedly injurious. Rats, Weasels, Minks, and Foxes destroy poultry; Wolves and Pumas kill domestic and game animals; Woodchucks or Groundhogs eat clover and various garden plants; Moles damage the lawns; Rats, Mice, and Gophers spoil and devour grain; Mice and Rabbits girdle fruit trees, thus killing them.

On the other hand, many mammals furnish food; _e. g._, Rabbits, Elk, and Deer. This was more important in pioneer times than at present. Many furnish furs used as articles of clothing; _e. g._, Racc.o.o.n, Fox, Muskrat, Mink, Otter, Marten, Mole, New York Weasel and other northern weasels in their winter coats.

[Ill.u.s.tration: POLAR BEAR

An expert swimmer. Feeds upon seals, fish and other animal food. Range: Arctic regions of the world. Habitat Group in American Museum of Natural History.]

Many furs are usually sold under trade names that are entirely different from the true name of the animal. A list of a few fur-bearing mammals of the United States having trade names differing from the true names follows:

_The True Fur_ _The Trade Name_ Dark blended Muskrat Russian Otter Mink blended Muskrat Natural River Mink Natural Muskrat[6] River Mink Natural Jersey Muskrat River Sable Plucked and Seal-dyed Muskrat Hudson Seal Plucked and Seal-dyed Muskrat Aleutian Seal Skunk Black Marten Striped Skunk Civet Cat N.Y. Weasel in winter pelage Ermine

[Ill.u.s.tration: SKUNKS--MOTHER AND YOUNG HUNTING FOR GRa.s.sHOPPERS AND CRICKETS

Noted for its ability to emit a most unpleasant odor when disturbed.

Range: Eastern North America. Portion of Group in American Museum of Natural History.]

[Ill.u.s.tration: MINK

A cousin of the Weasel and Otter, the Mink feeds upon frogs, crayfish, mice, bird's eggs, etc. Range: This and closely related forms over most of United States, Canada, and Alaska. From Group in American Museum of Natural History.]

A few suggestions for observation or study:

1. What peculiar instinct or habit has the Opossum developed?