PARK AND CE^METERY 
97 
the trees grows, but it is not all that is to be desired. 
The guard contracts and chafes the tree. Even when 
supported by uprights its looseness tends to cause 
chafing. 
If the height of the trees allow, the guards should 
extend high enough to prevent horses gnawing above 
its top. About seven and one-half feet will ordinarily 
suffice. 
After the trees are planted, the ground immedi- 
ately surrounding them should be kept under thor- 
ough and constant cultivation for at least three years. 
The area so treated will vary in size according to the 
dimensions of the planting strip and the size of the 
tree, but ordinarily it should be about 4 feet square. 
Except where tramping by pedestrians would compact 
the soil ; and for trees having trunks 4 inches or over 
in caliper we should prefer to omit the use of iron 
gratings. 
A METHOD OF SUPPORTING A SERVICEABLE METHOD 
CLOTH PROTECTOR OF TYING. 
ON A TREE- 
As an assistant to a well aerated soil and possibly 
as an agent in conducting carbon to the roots of the 
tree by the rain water, walks should be preferably 
paved with brick. Likewise the entrance driveways 
intersecting the planting strips might be paved with 
brick in localities where such material is adapted. 
In such cases the interstices between the brick should 
not be filled with tar, cement, asphalt or any mate- 
rial which is waterproof or likely to cause a concrete 
body. 
Special attention should be given to the watering 
of trees during the first year after planting. During 
the second year watering will also be necessary if the 
weather is unfavorable during a long period. During 
the first year water should be given before the gen- 
eral aspect of the established vegetation in the vicin- 
ity indicates that a drought is causing it suffering un- 
der ordinary circumstances. After the second year 
most trees will adjust themselves to their surroundings 
as regards water and no further attention need be 
given until from 5 to 10 years later. The method then 
well adapted is that described in a previous edition of 
Park and Cemetery, and used in Dresden, Germany. 
Such a system might be installed the same year it is to 
be used or at the time of planting the trees. This sys- 
tem has the additional advantage of tending to help 
the gas escape from the soil. To construct a barrier 
to the free passage of gas from street gas mains 
could perhaps be only done at a prohibitive cost. 
Such an arrangement might lie effected by slate slabs 
sunk vertically into the ground at the curb line and ex- 
tending from the surface of the ground to a depth of 
six feet. It would be necessary to make it continu- 
ous and cement the joints. Until some similar or 
equally efficient arrangement, as for instance tun- 
nels, to enclose the conduits are constructed in the 
streets, or until some chemical absorbent which would 
attract the gas in the soil, is made available and 
practical the drain tile water system will be found 
very desirable. 
Pruning is essential to the proper development 
of most street trees. It is usually done most fla- 
grantly and with empiricism. Pruning is pardonable 
only when a broken limb requires smooth surgical 
dressing ; when an old or decrepit tree needs re- 
juvenating; when an irregular or misshapen tree 
should be trained into one of symmetry or a deliques- 
cent to an excurrent stem, or an equally justifiable rea- 
son. The fact is frequently ignored or not understood 
that the roots of a street tree are unnaturally confined 
or restricted, and to avoid thinness of crown, top- 
heaviness, disease, devitalization , etc., the branches of a 
tree should be pruned and trained to balance the root 
system. Such pruning should be systematic and 
consistent with a single policy and in accordance with 
the laws to which vegetation is subject. A good 
policy is one that takes into account the natural out- 
line of a species, the density of twigs and foliage, the 
tracery of its twigs ; the various forms at different 
periods of its development, etc. And of such trees 
which require pruning few have their beauty en- 
hanced by the heroic "healing in” of old limbs. 
Thinning should often have been the method where 
that of cutting back has been adopted. If trees are 
systematically and attentively cared for there is seldom 
cause to remove limbs over three inches in diameter. 
These would ordinarily be dead, decaying, broken or 
diseased portions. 
Cuts made in the operation of pruning should 
