if 
12 BULLETIN 816, U. S. DEPARTMENT OF AGRICULTURE. 
Among those available are some that will grow under extremely 
trying conditions. Kinds can be found that will thrive wherever it 
is suitable for human beings to live. If it is impossible to grow trees. 
on a street, as a health measure that street should be closed for 
human use until conditions are so improved that it will support 
trees. 3 
More kinds will thrive under suburban conditions where only a 
small portion of the roadway is covered by animpervious coating, where 
the parking spaces are liberal, and where the street is lined with 
P15298HP 
Fic. 10.—A business center relieved by a parking with Carolina poplars. Macon, Ga.; late summer. 
open lawns than under the conditions in a city, where the street is 
covered with a water and air proof coating and the sidewalks with 
an impervious material, where parking spaces are limited, and where 
adjoining lawn areas are small or lacking. By a careful selection of 
kinds, all conditions in a city can be met. In some places bad condi- 
tions could have been improved greatly by a little forethought; in 
others, such conditions can be bettered. These details, like many 
other matters connected with city planning, have been ignored, but 
should be considered immediately, especially by villages and small 
cities. Figure 6 shows how an opportunity for creating a beauty 
spot has been lost sight of, while figure 10 shows how a city has 
utilized less ground to increase the comfort and attractiveness of its 
business center. 
A common mistake in ambitious young cities and many old ones 
is to pave more of the width of the street for traffic purposes than is 
- 
