302 The Principles of Fruit-growing 



(after Hedrick) shows good results from moderate pruning. 

 It is probable that a large number of reported instances 

 of death due to heavy pruning of winter-injured trees are 

 of such trees as would have died or not fully recovered 

 under any treatment. 



Winter-killed plants often retain sufficient vitality to 

 leaf out or to bloom, and sometimes even to begin growth, 

 but when the stored vitality of the tissues is exhausted 

 the plant perishes. This explains the phenomenon which, 

 after a bad winter, nearly always puzzles the inobservant 

 fruit-grower, of trees starting into feeble growth and then 

 suddenly dying when warm and dry weather approaches. 

 Winter-injured trees should not be allowed to bloom or to 

 bear until they are fully recovered. Such trees are very 

 liable to attack by the flat-headed borer, pine-hole borer 

 and other things. 



The physiological character of winter-injury is obscure, 

 but it is probably in the nature of desiccation or the with- 

 drawal of moisture from the cells. The greater the quan- 

 tity of moisture in the tissue, the greater will be its loss 

 under conditions of cold and the greater the injury; and 

 this is probably the reason why a late growth of twig is 

 likely to be so disastrous if the winter is severe. There is 

 much that the grower can do to prevent winter-killing, as 

 well stated by Reddick: "It is certainly advisable to 

 recommend (1) that orchards be plowed early in the 

 spring (not in June as is frequently the case) and receive 

 thorough cultivation early in the season, in order to give 

 the trees every advantage of conserved moisture. (2) 

 That cultivation cease not later than August 1, in order 

 to start the trees into maturation. (3) That a cover- 

 crop, or robber-crop, be planted to take care of excess 

 moisture in the autumn, Such a crop would seem to 



