Street Trees. 323 



sacrificed. Citizens who value their. trees highly and yet strongly oppose 

 the removal of a few specimens for the good of those remaining, seldom 

 realize the extent of their error. Mere cutting out may not restore the 

 injured trees, if the work is not performed very early in the life of the trees. 

 Every town and city possesses trees that are suffering from this 

 evil of overcrowding. Each community should designate some intelli- 

 gent person to direct the work of caring for the pruning of such trees, 

 and who, despite false sentiment, will accomplish the work. 



(10.) Injury from wire labels. 



This injury occurs in young trees which have been labeled in the 

 nursery row and planted in the permanent places without the removal 

 of the labels. The girdling of a tree, whether it be large or small, does 

 not necessarily mean its subsequent death, because some trees more or 

 less outgrow the injury and many have been saved by bridge-grafting 

 the wounded part. This is done by trimming smooth the edges of the 

 girdled part and inserting cions of the same species under the bark in such 

 a way that the wound is bridged over. (Fig. 243.) These cions, being 

 placed very close together around the stem, become united at the ends 

 with the old trunk and serve to conduct the elaborated food material 

 down to the lower parts of the tree. During- the period of uniting, the 

 cions are covered with grafting wax much as is an ordinary graft, and 

 no shoots developing from buds on the cions are permitted to grow. 

 In time, as the tree develops, the wounded part is entirely healed. 



II. Protection and Pruning of Street Trees. (Pages 323-337) 

 A. Methods of protecting trees. 



Street trees require protection from many contingencies. The three 

 most common sources of injury against which trees must be mechan- 

 ically protected are, the careless breaking down of young saplings, the 

 abrasions of the trunk caused by wagon wheels, and the drying out of 

 the roots because of lack of water supply. The methods for protection 

 against the many general sources of injury have been outlined, and it 

 is only the protection from these more important injuries which need 

 to be discussed further. 



(i). Protection for young or transplanted trees. The greatest menaces 

 to the normal development of a young sapling, planted on the highway, 

 are reckless driving and the tying of horses to the tree. As a preventive 

 against the first, all young trees in dangerous positions should be pro- 

 vided with supports to keep them erect and to protect them against 



