260 PRINCIPLES OF PLANT CULTURE 



(d) By obstructing the growth current. This is accom- 

 plished by ringing (416), by notching (416) and by peeling 

 the stem (72). 



When ringing is practiced, the .width of the belt of 

 bark removed should usually not be so great that the 

 wound cannot heal over the same season by the callus 

 formed on the upper edge of the ring (79), and it must 

 be made sufficiently early to give time for healing. A 

 wider ring will sometimes heal if the ringing tools are 

 not inserted deeper than the cambium layer (80). In 

 the grape vine, in which ringing is often practiced to 

 increase the size and earliness of the fruit, the width 

 of the belt removed is less important, since the canes 

 that have borne fruit are generally removed in the an- 

 nual pruning. But in fruit trees, the belt of bark removed 

 should not much exceed one-eighth inch in width. Simply 

 cutting through the bark with the pruning saw often 

 accomplishes the desired end. 



Notching above or below a bud or twig affects it much 

 as ringing affects the entire ringed member. Notching 

 below a bud or twig, therefore, checks its growth, and 

 is often followed by fruiting in that part. 



Peeling the stem has sometimes been practiced to make 

 barren trees fruitful (72). It is a hazardous operation 

 at best, and should only be used as a last resort. It is 

 accomplished by making two cuts around the trunk, 

 usually several inches apart, and just through the bark, 

 with one or more vertical cuts between them, after which 

 the bark between the circular cuts is carefully peeled 

 off. It should only be performed during a period of 

 very rapid growth, and at a time when the wood is well 

 supplied with reserve food, i.e., some time after the 

 tree has put out leaves. It is most likely to succeed in 



