326 FUNDAMENTALS OF FRUIT PRODUCTION 



should be done before growth starts. There is a. general tendency to 

 overestimate damage and immediately after a freeze many orchards 

 have been taken out which would have recovered in time had they been 

 allowed to remain. Trees with any considerable injury to the trunk 

 should by no means be allowed to bear fruit in the season following the 

 injury." 



Observations by Mer^^^ on oaks may explain the injurious effects 

 of very heavy pruning. Investigating old winter injuries of the "black 

 heart" type, he found considerable starch still in the injured wood but 

 little in the wood subsequently laid down, indicating that the tree was 

 unable to withdraw starch from the injured tissue. This suggests that 

 if the injury is extensive the tree will have difficulty the following spring 

 in securing sufficient carbohydrates to sustain growth until a supply can 

 be secured from the new leaves. If the pruning is heavy enough to 

 remove all the buds which make new growth most readily the difficulty 

 must be increased. If, however, no buds are removed the scanty carbo- 

 hydrate supply is apportioned to so many growing points that none 

 receives enough to sustain growth until it can become self-supporting and 

 the tree dies of carbohydrate starvation. 



Hardiness in wood and in bud are not always combined in the same 

 variety. Elberta, generally considered hardy in wood, seems tender in 

 the fruit buds. Hedrick,^^ reporting a questionnaire of New York and 

 Michigan peach growers, states their selections for wood hardiness as 

 follows: For New York in order named, Crosby, Hill's Chili, Stevens' 

 Rareripe, Gold Drop and Elberta; for Michigan, Hill's ChiH, Crosby, 

 Gold Drop, Kalamazoo and Barnard. Jaques Rareripe, Wager, Carman, 

 Belle of Georgia, Hale's Early, Champion and Greensboro are listed as 

 hardier than the average in this respect. Early Crawford, Late Craw- 

 ford, Chair's Choice, St. John and Niagara are rated as the five most 

 tender in wood of the varieties commonly grown in New York. Salway 

 is listed as tender in Michigan. 



In fruit buds. New York growers find greater hardiness in Crosby, 

 Hill's Chili, Triumph, Gold Drop, Stevens' Rareripe and Kalamazoo; 

 Michigan growers find Hill's Chili, Gold Drop, Crosby, Kalamazoo and 

 Barnard hardiest. Concerning the five most tender varieties in bud 

 there is entire agreement in New York and Michigan as to the order of 

 their tenderness: Early Crawford, Late Crawford, Chair's Choice, 

 Reeves' Favorite and Elberta. The Peento group is extremely tender. 



The Cherry. — Sweet cherries are generally known to be far more tender 

 than the Dukes, Amarelles and Morellos. As outlined by Finch'^'* the 

 northern range of cherries is marked by the mean winter temperature of 

 about 16°F. For the three coldest of the pomological districts into 

 which the United States is divided in the fruit catalog of the American 

 Pomological Society only one variety of sweet cherry, Black Tartarian 



