Drouth, floods and erosion of soils have been common experiences. The preservation of forest cover, especially at the headquarters of the Yalu and Tumen in the northern part of the country, is aimed at. For this purpose the government has taken all forests under its care. All private owners or lease holders must report their holdings and have their property listed, and in case of failure to do so the property is forfeited. The government may then expropriate, or else regulate the cutting, or, where protective functions of the forest cover require it, may forbid cutting altogether. A forestry school is also part of the program. UNITED STATES OF AMERICA. _Report upon Forestry_, 1878-9, by Dr. F. B. Hough; contains references to the earlier history of forest development. _History of the Lumber Industry_, by J. E. Defebaugh, 1906-7; is valuable as a reference to statistical matter. _Report upon Forestry Investigations of the United States Department of Agriculture_, 1877-1898, by B. E. Fernow. House Document No. 181, 55th Congress; contains amplifications of the matter contained in this chapter. Annual and other reports issued by the Department of Agriculture, by the various State Forest Commissions, and Forestry Associations. For latest developments, consult _Conservation (American Forestry)_ and _Forestry Quarterly_. The great and exuberant republic of the United States, vast in extent and rich in natural resources generally, excelled and still excels in extent, importance and value of her timber resources; and, having only lately begun to inaugurate rational forest policies, promises to become of all-absorbing interest to foresters. The marvelous growth of the nation, which from three million in 1780 had attained to a population of 76 million in 1900, and, by the last Census numbered around 92 million people, has been the wonder of the world by reason of its rapid expansion; and yet the limit is far from being reached. Annually some three-quarters of a million or more immigrants from all parts of the world arrive, and there is still room and comfortable living for at least another 100 million, if the resources are properly treated. The large land area of nearly two billion acres (over three million square miles) is undoubtedly the richest contiguous domain of such size in the world, located most favorably with reference to trade by virtue of a coast line of over 20,000 miles, and diversified in climate so as to permit the widest range of production.