TREATMENT OF WOUNDS 45 



by the tree's growing against objects which do not 

 give way before it, with the result that the bark 

 is killed locally, or at least fails to make any 

 growth. Such wounds are made by the plank 

 seats which are frequently seen pried in between 

 two trees. Both trees are sure to be injured 

 sooner or later if the plank is not taken out every 

 few years and cut down a little. In such cases if 

 the compressed bark is dead it must be removed. 

 If not, it should be cleaned off, so as to be free to 

 grow. The tree which has had wires wound 

 around it, or at least stapled to one side, is another 

 frequent patient of the arboriculturist. The dan- 

 ger in such cases is that the wire will girdle or 

 partially girdle the tree. All wire must be pulled 

 out if the bark has not actually closed and joined 

 over it. Of similar character is the tree which 

 has outgrown its wire guard. If parts of the 

 guard have become imbedded in the trunk, they 

 need not be removed if such a course would re- 

 quire cutting the calluses closing over them. The 

 bark of the meeting calluses should be pared down 

 and perhaps slit in places, to encourage their 

 growth. If the tree is vigorous and the calluses 

 are scraped occasionally, they will ultimately grow 

 together organically and permit the free flow of 

 the sap down the cambium. 



Another kind of bark wound is caused by the 

 rubbing together of two limbs. Something more 



