32 TREATISE ON 



This graft is performed during in the same seasons as the bud graft. It can serve to 

 demonstrate the general principles of grafting from the standpoint of a gardener rather 

 than of a scientist. 



A tree grows only by adding new layers, cortical as well as woody ones. These 

 layers form between the wood & the bark as though they were in a mold that shapes them 

 and that holds & keeps the proper material for producing them. We can think of the outer 

 woody surface of a tree as though it were the inner mold for a new layer, & the inner 

 cortical surface as its outer mold. 



If both of the molds, or just one of the two, is broken, the new layers stop growing 

 over the injured part until it's scarred over with a new cortical sheet. This sheet emerges 

 from the edges of the wound & spreads over the exposed region little by little to restore 

 the mold. Furthermore, a tree whose bark has been badly damaged forgets about getting 

 larger & is concerned only with restoring the integrity of its bark. Dress the wound with a 

 plaster of earth, turpentine, or some other preparation of vegetable matter to protect it 

 from contact with air & from drying out. It will heal up more quickly because the plaster 

 in some way takes the place of the outer mold and helps & promotes the formation of a 

 new layer of bark. But if you apply to this recent wound a completely fresh piece of bark 

 from a similar tree that has the same dimensions as the wound, a thin cortical sheet will 

 form between it and the wood of the tree. A similar sheet emerging from the edges of the 

 wound between the tree's wood and bark will fuse together with it. The mold thus 

 restored, the woody layers will continue to develop. 



Let's now think of the operation on a stock 



