GRAFTING 73 



ingly before autumn. There is a tendency for such 

 a tree to be too ambitious and to grow its new crop 

 of shoots right up into freezing weather. For either 

 mediate or immediate summer grafting my experi- 

 ence to date includes the idea of leaving one good 

 sized top branch unharmed and of grafting the stubs 

 of all cut branches below that point. The top branch 

 may be sawed off one or two years later, and in 

 falling it is pretty sure to rake out some very beau- 

 tiful grafts as a farewell expression of its sentiment 

 toward the whole procedure. The question of the 

 size of the sap leader (the branch to be left at the 

 top) is one requiring a good deal of judgment. If 

 it is too large the tree retains a spirit of contentment 

 and may not send new shoots into activity. If the sap 

 leader is too small it may not maintain nourishment 

 of the root system sufficiently to make the best gain 

 on the whole. This point is one requiring so much 

 judgment and relates to particular varieties of trees 

 in such a way that no rules are to be laid down. 

 Sometimes in summer grafting when nothing but a 

 small sap leader has been left, the leaves turn brown 

 shortly and die, buds mature, the branch takes a 

 rest for a few days and then starts off into new 

 activity. As yet I have no explanation for this phe- 

 nomenon. In a speculative way one thinks of bursting 

 of cells in leaves from extra sap pressure or per- 

 haps of enzymic poisoning of the cells in the leaves 

 by materials which would ordinarily be eliminated by 

 excretion processes. The top-working of very large 

 trees includes the idea of so much labor that it is 



