PLANTING AND MAINTENANCE 133 



or at its base. These are robbers, for they are 

 always of rank, lush growth that takes up more 

 of the tree food on its way to the leaves and 

 branches above than would seem possible. 



There are two principles involved in pruning 

 which must be understood and remembered, if 

 the work is to be done intelligently. These are 

 fixed by the system of growth common to all 

 plants — that is, growth at the tips or extremi- 

 ties. Branches lengthen, branchlets lengthen, 

 and new branches form always by means of 

 terminal or tip buds, and all growth is invari- 

 ably carried on in this way. The run of sap is 

 always to the plant's remotest part, and inter- 

 mediate growth is taken care of incidentally 

 rather than primarily. If a terminal bud is 

 injured or destroyed, therefore, the sap, coming 

 strong and full to the point where it was, stimu- 

 lates the buds next below it into abnormal ac- 

 tivity and these make haste to rush out into 

 branches, each striving for the place of leader 

 until one finally does gain an advantage which 

 nips the others because it then appropriates the 

 leader's share of nourishment. 



Removal of terminal buds, therefore, will al- 

 ways thicken growth rather than thin it; so in 

 pruning to thin out remember that it is not 

 enough to do less than remove an entire branch 



