l6 THE AMERICAN APPLE ORCHARD 



upon them. Thus the roots were killed in many cases 

 where the tops were able to withstand the weather. 



In cases where root killing is likely to occur from 

 time to time that is, in sections where severe freezing 

 is likely to come when the ground is not covered by 

 snow special precautions should be taken to prevent 

 this sort of damage. The best of these is to propagate 

 the apple upon a very hardy stock; and probably the 

 best of these stocks is the Cherry crab (Pirus 

 baccata). Unfortunately these stocks are available 

 only in small quantities and at comparatively high 

 prices. Trees propagated on these roots cannot be 

 bought in any ordinary nursery. The next best pre- 

 ventive of root killing, and the one easiest to adopt, 

 is the cover crop. A good heavy cover of clover, 

 alfalfa, or vetch gives the ground some protection in 

 itself and helps to hold whatever snow may fall. 



