The forest is a sanitary agent. It is constantly eliminating impurities from the earth and the air. Trees check, sweep, and filter from the air quantities of filthy, germ-laden dust. Their leaves absorb the poisonous gases from the air. Roots assist in drainage, and absorb impurities from the soil. Roots also give off acids, and these acids, together with the acids released by the fallen, decaying leaves, have a sterilizing effect upon the soil. Trees help to keep the earth sweet and clean, and water which comes from a forested watershed is likely to be pure. Many unsanitary areas have been redeemed and rendered healthy by tree-planting.
Numerous are the products and the influences of the trees. Many medicines for the sick-room are compounded wholly or in part from the bark, the fruit, the juices, or the leaves of trees. Fruits and nuts are at least the poetry of the dining-table. One may say of trees what the French physician said of water: needed externally, internally, and eternally! United we stand, but divided we fall, is the history of peoples and forests. Forest-destruction seems to offer the speediest way by which a nation may go into decline or death. "Without forests" are two words that may be written upon the maps of most depopulated lands and declining nations.
When one who is acquainted with both history and natural history reads of a nation that "its forests are destroyed," he naturally pictures the train of evils that inevitably follow,—the waste and failure that will come without the presence of forests to prevent. He realizes that the ultimate condition to be expected in this land is a waste of desolate distances, arched with a gray, sad sky beneath which a few lonely ruins stand crumbling and pathetic in the desert's drifting sand.
The trees are our friends. As an agency for promoting and sustaining the general welfare, the forest stands preëminent. A nation which appreciates trees, which maintains sufficient forests, and these in the most serviceable places, may expect to enjoy regularly the richest of harvests; it will be a nation of homes and land that is comfortable, full of hope, and beautiful.