STREET TREES. 17 
cussion of the strong and weak points of the different kinds will be 
found with the description of the kinds farther on in this bulletin. 
Region 1.—Region 1 comprises the mild humid portion of the northern Pacific coast 
-east to the Cascade Mountains, including the western third of Washington and Oregon 
and a portion of northern California. The trees native to western Europe are adapted 
to this region, as the climatic conditions are quite comparable. Most of our American 
trees also succeed here. 
Some of the desirable varieties for street planting in region 1 are the Oregon, Norway, 
sycamore, and sugar maples; California walnut; tulip; European linden; basswood; 
sycamore; London plane; white and European ashes; English and American elms; 
English, red, and pin oaks; ginkgo; and the black locust. 
P20366HP 
Fic. 17.—Outline map of the United States, showing the regions within which essentially similar con- 
ditions for tree growth exist. 
Region 2.—Region 2 is that portion of California lying between the Sacramento and 
San Joaquin Valleys and the Pacific Ocean. Many varieties of trees will succeed 
here if given water. Because of the lack of water, unless specially irrigated the more 
drought-resistant species should be used. 
Among the deciduous trees useful for this region are the London plane; the Cali- 
fornia and common sycamore; English, Huntingdon, and American elms; Oregon, 
Norway, sycamore, and English maples; white, green, and European ashes; red, 
English, and pin oaks; European linden; basswood; California walnut; honey and 
black locusts; horse-chestnut; Albizzia; and the Japanese varnish tree, or Sterculia. 
Evergreen trees which will probably be successful in region 2 are the Eucalyptus ! 
in variety, acacias, rubber, magnolia, California live oak, Victorian and poplar-leaved 
bottle trees, and in the southern portions the California pepper, silk oak, and: jaca- 
randa. Palms are much planted, but they do not make good street trees except where 
a formal effect instead of shade is desired. 
1 Some cities have ordinances against the planting of certain trees because their roots sometimes ob- 
struct sewers. Among these trees are the Eucalyptus in California and some of the poplars in several 
of the States. 
137389 °—19—Bull. 816-——3 
