CARING FOR SHADE TREES 
137 
letter U so as to hold the tree from possible contact with 
the opposite side of the guard. The guard should be 
kept around the tree for several years, until the trunk 
has reached a diameter of six inches at the very least, and 
in some locations it should be permanent. With the 
growth of the trunk careful watch must be kept to see 
that the tree does not become cramped or choked by the 
guard. Neglecting to remove a guard when it has been 
outgrown is certain to cause injury. In many cases, 
the expansion of a trunk within an unyielding guard has 
resulted in girdling the tree with a wound causing death. 
It is important to keep a guard painted and repaired. 
The need of repairs to this protective device is so fre¬ 
quent as to emphasize the danger to which the tree itself 
would have been exposed if there had been no such 
buffer to parry the blows. 
