Forests are vast and valuable expanses; the necessity for government supervision has long been recognized and is today employed virtually throughout the world. The earliest known instance of organized reforestation was in Germany in 1368, and by the mid-18th cent. the practice was well established also in neighboring Austria, Switzerland, and France. German immigrants to the United States (notably Carl Schurz, the first Secretary of the Interior) were instrumental in conserving the new forest lands. After the Timber Culture Act (1873), extensive planting began, although at first mostly in an attempt to forest the plains and prairies. Under President Theodore Roosevelt the first public forests were set aside (see National Forest System). The Civilian Conservation Corps, instituted by President Franklin D. Roosevelt, planted about 2.25 billion trees in the decade from 1933 to 1942, and efforts in forestry have increased significantly in recent years. Today about 27% of U.S. forest is under public ownership, 17% as national forests administered by the Forest Service of the Dept. of Agriculture.