160 Landscape Gardening 



compact than the American species, and valuable where a less 

 spreading tree is desired. All of the elms are subject to the 

 attack of the elm leaf-beetle, canker-worm, the elm-scale, 

 and other insects, and need close attention to prevent their 

 being seriously injured. See chapter on insects, page 261. 



Sugar-maple {Acer saccharum), (Fig. 90). — Perhaps no 

 tree is so largely planted for streets and roadways as 

 this, and it has many valuable qualities. It is clean, up- 

 right, easily transplanted, and grows rapidly, but is some- 

 what subject to disease and the attack of the maple-tree 

 borer, maple-louse, and other insects and fungous pests 

 which have often destroyed large trees and broken into 

 many a fine avenue of stately growth. 



Silver Maple {A. saccharinum), Fig. 91.— This rapidly 

 growing tree is being largely planted in many places. It 

 is a clean tree of great beauty, and thus far has shown no 

 tendency to disease or the attack of insects. The tendency 

 it has of forming several main forked branches must be 

 overcome by heading in all but the central leading branch, 

 until the tree has become well established, as with the elms, 

 shown in Fig. 26. This species thrives on all kinds of soil, 

 but makes the best growth in a rather moist, deep soil. 



White Ash (Fraxinus americana). — In growth this 

 tree is very much like the sugar-maple with a little less of 

 the conical form. The foliage is of a dark, rich color and 

 free from insects and fungous pests. It is rather easily 

 broken down by ice and wind-storms, and requires a heavy 

 soil for its best development. 



Red Oak (Quercus rubra). — Of the oaks this and the 

 next species are the best for street decoration, but they can 

 be used along narrow roadways by training only the branches 

 high. This is best done by keeping the lower branches 

 clipped in, as in Fig. 91a, and when strong main branches 

 have been formed high enough to be above all danger 



