INFLUENCE OF FORESTS ON THE HUMIDITY OF THE AIR AND THE EARTH: _a_, AS INORGANIC MATTER; _b_, AS ORGANIC--WOOD MOSSES AND FUNGI-- FLOW OF SAP--ABSORPTION AND EXHALATION OF MOISTURE BY TREES--BALANCE OF CONFLICTING INFLUENCES--INFLUENCE OF THE FOREST ON TEMPERATURE AND PRECIPITATION--INFLUENCE OF THE FOREST ON THE HUMIDITY OF THE SOIL-- ITS INFLUENCE ON THE FLOW OF SPRINGS--GENERAL CONSEQUENCES OF THE DESTRUCTION OF THE WOODS--LITERATURE AND CONDITION OF THE FOREST IN DIFFERENT COUNTRIES--THE INFLUENCE OF THE FOREST ON INUNDATIONS-- DESTRUCTIVE ACTION OF TORRENTS--THE PO AND ITS DEPOSITS--MOUNTAIN SLIDES--PROTECTION AGAINST THE FALL OF ROCKS AND AVALANCHES BY TREES--PRINCIPAL CAUSES OF THE DESTRUCTION OF THE FOREST--AMERICAN FOREST TREES--SPECIAL CAUSES OF THE DESTRUCTION OF EUROPEAN WOODS-- ROYAL FORESTS AND GAME LAWS--SMALL FOREST PLANTS, VITALITY OF SEEDS-- UTILITY OF THE FOREST--THE FORESTS OF EUROPE--FORESTS OF THE UNITED STATES AND CANADA--THE ECONOMY OF THE FOREST--EUROPEAN AND AMERICAN TREES COMPARED--SYLVICULTURE--INSTABILITY OF AMERICAN LIFE. _The Habitable Earth Originally Wooded._ There is good reason to believe that the surface of the habitable earth, in all the climates and regions which have been the abodes of dense and civilized populations, was, with few exceptions, already covered with a forest growth when it first became the home of man. This we infer from the extensive vegetable remains--trunks, branches, roots, fruits, seeds, and leaves of trees--so often found in conjunction with works of primitive art, in the boggy soil of districts where no forests appear to have existed within the eras through which written annals reach; from ancient historical records, which prove that large provinces, where the earth has long been wholly bare of trees, were clothed with vast and almost unbroken woods when first made known to Greek and Roman civilization;[112] and from the state of much of North and of South America when they were discovered and colonized by the European race.[113]