134 
TREES AS GOOD CITIZENS 
ounce per tree may be used. Nitrate of soda is a strong 
plant stimulant so needs to be used in small quantities at 
any one time but can be used more frequently. A year’s 
supply of the other ingredients may be applied at one time, 
using 4 to 12 ounces of the mixture per tree. For heavier 
soil the same ingredients are used but in different propor¬ 
tions, the formula calling for two parts of nitrate of soda, 
three parts of acid phosphate, one part muriate of potash 
and two parts of bone meal. The quantity to be used for 
each tree is the same as in the case of the lighter soil. 
This fertilizer should be evenly distributed and mixed 
into the soil in a thorough manner. Too liberal use of 
the chemical mixture will injure the roots. 
Protection from injury is essential to the young tree 
on the city thoroughfare. All of us have seen boys swing¬ 
ing on the slender stems as if the trees had been planted 
as a part of a public gymnasium. We have seen trees 
bent down till their tops touched the ground, by those 
who find pleasure in watching the flexible stem fly back 
to an upright position. We have seen trees die as a result 
of these and similar abuses, because of the loosening of the 
roots just at the time when it is most important that they 
should be allowed to gain firm foothold. We have seen 
men tie horses to the slender trees and have found the 
horses nibbling at the bark, to the serious injury of the tree. 
The horses are not to blame, of course, but this is no 
comfort to the man whose tree is ruined in the process. 
It was to prevent injuries from these and similar 
causes that the tree guard was invented. The loss of 
bark caused by horse bites frequently causes a wound 
which affects the tree’s whole future. With the growth of 
the trunk the old wound accumulates thick edges, invites 
decay and permits the entry of borers and the growth 
of fungus diseases. The death of the tree is apt to follow, 
