nia. Oaks
are abundant; they are especially characteristic of the Great Valley,
where they grow in magnificent groves. Up to 1910 national forest
reserves amounted to 27,968,510 acres. In 1909 Congress created a
national forest to include the big tree groves in Calaveras and Tuolumne
counties. One of the noblest redwood areas (that of Santa Cruz county)
is a state reservation (created in 1901). Even within reservations
almost all the merchantable timber is owned by private individuals. In
addition to native trees many others--especially ornamental
species--have been successfully introduced from various parts of the
world.

_Soil._--Sand and loams in great variety, grading from mere sand to
adobe, make up the soils of the state. The plains of the north-east
counties are volcanic, and those of the south-east sandy. It is
impossible to say with accuracy what part of the state may properly be
classed as tillable. The total farm acreage in 1900 was 28,828,951
acres, of which 41.5% were improved; since 1880 the absolute amount of
improved land has remained practically constant, despite the
extraordinary progress of the state in these years. Much land is too
rough, too elevated or too arid ever to be made agriculturally
available; but irrigation, and the work of the state and national
agricultural bureaus in introducing new plants and promoting scientific
farming, have accomplished much that once seemed impossible. The
peculiarities of the climate, especially its division into two seasons,
make Californian (and Southern Arizona) agriculture very different from
that of the rest of the country. During the winter no shelter is
necessary for live-stock, nor, during summer, for the grains that are
harvested in June and July, and may lie for weeks or months in the
field. The mild, wet winter is the season of planting and growth, and so
throughout the year there is a succession of crops. The dangers of
drought in the long dry seasons particularly increase the uncertainties
of agriculture in regions naturally arid. Irrigation was introduced in
Southern California before 1780, but its use was desultory and its
spread slow till after 1850. In 1900 almost 1,500,000 acres were
irrigated--an increase of 46% since 1890. About half of this total was
in San Joaquin Valley. California has the greatest area of irrigated
land of any state in the Union, and offers the most complete utilization
of resources. In the south artesian wells, and in th