250 



PRINCIPLES OF PLANT CULTURE 



exposure of unhealed wounds may cause damage from 

 drying, and invites infection by injurious fungi (320), 

 severe pruning is commonly best performed toward the 

 end of the dormant period, i.e., in early spring, because 

 healing is most rapid at the beginning of the growing 



Fig. 156. 



Fig. 157. 



Fig. 158. 



Fig. 156. — Pruning: showing the proper place to make the cut in 

 pruning. A wound made by a cut on the dotted line A-B will be 

 promptly healed. One made on the line C-D or E-F will not. In 

 Fig. 157 the lower branch was cut off too far from the trunk. 



Fig. 157. — Showing how to make the cut in pruning large branches. 

 The upper cut, all made from above, permits the branch to split down. 

 The left cut, first made partly from below, prevents splitting down. 



Fig. 15S. — Pruning to an outside or inside bud. Cut as in the figure, 

 the uppermost bud would form a shoot that tends to vertical. Cut on 

 the dotted line, the uppermost bud would form a shoot tending to hori- 

 zontal. 



season (72). Pruning should not, however, be done at a 

 time when sap flows freely from wounds, since this tends 

 to waste reserve food. In plants subject to this, such as 

 the maples and grape, pruning is probably best performed 

 just before or just after the sap-flowing period. 



418. Making the cut. — Since the movement of pre- 

 pared food is mainly from the leaves toward the root 



