230 PLANT PROPAGATION 



which the work is done among the limbs. Methods of 

 inserting the cions may vary in all these classes. 



299. Cion graftage is of three general kinds : bridge or 

 repair grafting, root grafting and top grafting. 



300. Bridge or repair grafting sometimes erroneously 

 called inarching, is not properly a propagation process, 

 but it may well be discussed here, because it may be the 

 means of saving valuable trees which have been injured 

 by mice, rabbits, hogs, human carelessness or accident. 



Unless the girdle has cut through the sap wood it is an 

 error to say that bridge grafting is necessary to establish 

 connection between root and top ; for the upward current 

 of sap passes through the sap wood and not through the 

 bark. It is correct, however, to say that the bridge es- 

 tablishes a connection between top and root, for the 

 downward flow of elaborated sap is through the bark 

 layers. As soon as the wound is discovered the operation 

 should be performed. If the injury occurs in winter the 

 wound should be protected to prevent drying. In spring 

 when the buds begin to swell the grafting should be done. 

 The operation is performed as follows (Fig. 187) : 



The injured, and perhaps dry bark, on both upper and 

 lower edges of the wound is pared back to living tissue. 

 Several cions are cut long enough to extend a little 

 beyond these trimmed edges, and inserted beneath the 

 bark both above and below, thus making little "bridges" 

 across the gap. The ends of the cion are cut obliquely, 

 to insure fitting of the cambium layers of cions and trunk. 

 It is often a help to bow the cions outward slightly, 

 because the spring thus formed aids in holding them in 

 place. But these and other minor details may be left to 

 individual preference. If placed an inch or so apart 

 around the trunk, enough cions should succeed to save 

 the tree. Both wound and cions should be completely 

 covered with grafting wax, preferably made warm so as 

 to fit into every chink and thus exclude air and water. 

 In a few years the cions will grow together and in time 

 lose their identity in a smooth trunk. 



