6 
Bulletin 96. 
The other idea is that when trees have nearly or quite com¬ 
pleted their growth the tops should be cut back—regardless of the 
size of the trunk or branches. Some trees, like the cottonwood, will 
stand such abuse fairly well, but they are mutilated for the rest 
of their lives. Fortunately many kinds of trees do not live long 
after such heroic treatment. 
Although shade trees usually need but little pruning, that which 
is needed should be done systematically, and the natural shape of 
the tree should always be borne in mind. Specimen trees should as 
a rule never be pruned except when they are planted, as mentioned 
above, and as occasional sprawling branches or bad forks are likely 
to be formed. Street trees likewise need but little pruning except 
that the head should usually be started about ten feet above the sur¬ 
face of the ground. In any case each tree should be allowed to as¬ 
sume its natural form as much as possible. 
Another mistake which is commonly made is that of planting 
trees too close together. One is naturally desirous of securing 
quick effects; and as a means of securing this end close planting is 
commendable, providing the surplus trees are removed as soon as 
they begin to crowd. But this appears to be a difficult matter for 
the average person to do. 
In some towns double rows of cottonwood trees, the trees 
ten feet apart in the row, may be seen, one on each side of the side 
walk. The result is a thicket of ungainly trees which serve no pur¬ 
pose that would not have been gained had there been but one row 
and the trees placed three or four times as far apart. 
The majority of trees on most streets should be planted 40 
feet apart. Then if quick effects are desirable, the rapid growing 
Carolina poplar may be planted temporarily between the slower 
growing kinds, thus making the trees 20 feet apart. The temporary 
trees should be removed at the first sign of crowding and those that 
remain will soon fill in the gaps. 
Most of the trees here mentioned are propagated ordinarily by 
seeds, a few by cuttings and layers, while some, as the elms, bass¬ 
wood, catalpa and black walnut, sprout readily from the stump. If 
one strong shoot is allowed to grow anew tree may be secured in a 
comparatively short time in this way. Seeds of most trees ripen in 
autumn and may be planted then where they are to grow, or they may 
be stratified and planted in spring. Stratification consists of mix¬ 
ing the seeds with moist sand, or alternate layers of seeds and sand 
which may be placed in barrels or boxes and kept out doors. The 
alternate freezing and thawing to which they are subjected during 
tne winter, when thus exposed, is necessary to enalzde the seeds 
of many trees to germinate. 
