PRUNING— THE SEASON 



445 



generally practiced in America, is therefore based on two assumptions, 

 both of which are fundamentally wrong. This is shown by some of 

 the more recent investigations in this particular field — notably those 

 in Virginia, 1^ West Virginia' and Utah.^' All these showed decreased 

 production of flower clusters or decreased yields of fruit following the 

 summer pruning of young trees just coming into bearing or with their 

 bearing habits not yet well established and all report an accompanying 

 decrease in vegetative growth. In one of the West Virginia experi- 

 ments the yield of the summer pruned trees averaged barely a third of 

 the yield from those receiving winter pruning. On the other hand 

 Bedford and Pickering^ in one series of experiments found flower-bud 

 formation following summer pruning greater by 13 to 41 per cent, than 

 following winter pruning, depending on the time of operation. Alderman 

 and Auchter,' who found summer pruning a considerable check to fruit 

 production in apple trees just coming into bearing, report no such general 

 influence on mature trees. Table 16 summarizes the yields obtained in 

 Idaho over a 7-year period from winter and from summer pruned plots. 

 In every variety under trial summer pruning resulted in an increased 

 yield. 



Table 16. — Average Yields in Pounds per Tree From Winter and yuMMER- 

 PRUNED Trees 



{After Vincent'^^) 



Variety 



Pruning 



1910, 1911, 

 pounds pounds 



1912, 

 pounds 



1913, 

 pounds 



1914, 

 pounds 



1915, 

 pounds 



1916, 

 pounds 



Total, 

 pounds 



29.0 

 33.9 

 13.9 

 13.9 

 13.2 

 20.0 

 29.0 

 .54 . 3 



95.5 

 95.5 

 52.5 

 58.5 

 85.1 

 99.5 

 67.0 

 123.2 



127.8 

 144.3 

 58.8 

 85.0 

 101.6 

 195.5 

 22.0 

 50.8 



257.4 

 252.1 

 76.8 

 80.0 



128.7 

 88.5 

 83.7 



1.59.0 



50.3 

 51.7 

 18.7 

 23.0 

 102.1 

 155. 6 

 6.2 

 27.2 



2.39. 4 

 272.1 

 105.7 

 160.4 

 197.3 

 108.3 

 177.4 

 215.5 



834.7 

 870.9 

 391.6 

 450.8 

 689.0 

 738.4 

 402.5 

 689.4 



In commenting on these increases Vincent^^ says: "If the entire orchard had 

 been summer-pruned there would have been an increase per acre during the 7 

 years as follows: Jonathan, 30.02 boxes or an increase of 4.28 boxes per year; 

 Rome, 49.7 boxes, or an increase of 7.1 boxes per year; Grimes, 50.6 boxes or an 

 increase of 6.07 boxes, per year; Wagener, 240.9 boxes or an increase of 34.4 

 boxes per year. Summer pruning therefore has increased crop production on all 

 the plats and quite substantially on the Wagener." 



In neither the mature West Virginia trees nor the Idaho trees was 

 summer pruning attended by an appreciably decreased vegetative 

 growth. 



