66 PRACTICAL ARBORICULTURE 
THE MAPLES. 
Almost the only maple used in your street planting and home grounds 
is the silver maple (deer dasycarpum). This, too, is a pioneer tree, probably 
the most rapid growing of the maple family. Properly pruned when young, 
and kept trimmed in at all times, it may be formed into a round head, but it 
requires constant pruning. The branches are brittle, very long, easily broken 
in wind, or with an accumulation of snow. It is a good tree to plant alter- 
nately with other somewhat slower growing trees, but is very unsatisfactory 
where exclusively used. 
Scarlet maple (lcer rubrum) is better; has a round head, is a quick 
grower, and is very handsome, as it colors its foliage in autumn. 
Sugar or rock maple (.dcer saccharinum) is one of the very best street 
trees in America and succeeds in Colorado. It is very free from insects. Its 
growth is slightly slower than the two first mentioned varieties, but its foliage 
is superb. It requires little or no pruning, and less water than the two swamp 
maples. Its home is on rolling and mountainous lands; has a tap root which goes 
deep after moisture and food. 
Norway maple (Acer platanoides) is an excellent, hardy tree, not a slow 
grower if well cared for. 
GINKGO 
This tree was imported from Japan some forty or fifty years ago and is 
among the finest avenue trees of Washington City. 
It is growing finely in Colorado and every other state in the Union. The 
leaves are unique, bright green foliage, fan-shaped, narrow at the stem end. 
Its fruit, a delicious nut, with paper shell, enclosed in a disagreeable fruit 
pulp, the size of a plum. ; 
Under good culture its growth is by no means slow. It is suited to the 
lawn better than as a street tree. 
RUSSIAN OLIVE 
is a fine arid region tree; very satisfactory and numerous at Denver and some 
at Colorado Springs. Its silvery foliage gives variety to surrounding trees. 
TULIP TREE 
(Liriodendron tulipifera) is the grand forest tree of Indiana and elsewhere, 
called yellow poplar. It is a clean, rapid growing, handsome street tree, or for 
the lawn. A few are growing in Denver, and I have no doubt it will be 
perfectly satisfactory here. Rather difficult to transplant, like the Magnolia 
family; and should be removed only in spring. Small trees are more success- 
ful than larger ones. 
LINDEN OR BASSWOOD 
grows well in Colorado and makes a good dense shade, having a round head 
and being a handsome tree. 
When trees of this smooth-like bark are trimmed up with long trunks, 
