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 

 buifer to parry the blows. 



