PRUNING 257 



that has actually commenced to split down may often 

 be saved by passing an iron bolt through it and the re- 

 mainder of the trunk. A bolt thus inserted may become 

 entirely inclosed by later growth. 



sass* 



FIG. 165. Apple tree pruned with open head, to admit abundant light. 



426. Stimulative pruning depends upon the principle 

 that the suppression of growth in one direction tends 

 to stimulate it in others. Stimulative pruning may be 

 employed either to stimulate growth of leaves, branches 

 and roots, or of flower-buds. 



