The movement was materially strengthened also through the withdrawal of
large areas of the public domain from private entry. Thus 148,000,000
acres of forests and 80,000,000 acres of coal land were withdrawn during
President Roosevelt's administrations.
Directly connected with the problems of conservation are those of
irrigation. The so-called arid regions constitute two-fifths of the
area of the United States, or some 1,200,000 square miles. Of this vast
region, it has been estimated that about one-tenth can be irrigated to
advantage. By the end of the year 1908, some 13,000,000 acres had been
reclaimed, or nearly one-third of the total amount suitable for