PRUNING— THE SEASON 



443 



Table 15. — Growth Records of Summer and Winter-pruned Apple Trees in 



Idaho 



(After VincenV^) 



tissue formation, active growth ensues. This apparently is the explana- 

 tion of the results obtained with young peach trees in New Jersey^ and 

 with young apple trees in Oregon, ^i Soil conditions were such and the 

 pruning was such, in time, kind and severity, that a vigorous new vegeta- 

 tive growth was promoted following the pruning and terminal bud forma- 

 tion was completed at a considerably later date. This condition may 

 frequently result in an actual increase of food reserves at the time of leaf 

 abscission, especially in sections with a late growing season, because of the 

 greatly increased leaf surface. On the other hand if the pruning is of 

 such character that carbohydrates and other elaborated foods are re- 

 moved in considerable quantity and if it is done at a time when soil and 

 tree conditions do not stimulate later growth the same season, there is 

 not only an immediate reduction in size but reserves for the following 

 season are depleted and growth the next year will be correspondingly 

 restricted. Summer pruning under such conditions has a distinct 

 dwarfing influence. 



In conclusion, then, it may be stated that summer pruning does not 

 necessarily have either a dwarfing or an invigorating influence. It 

 may have the one or the other, depending on the severity, kind and 

 time of pruning (as related to the state of development of the plant, 

 rather than to the exact date on which the pruning may be done). 

 Environmental conditions also, particularly nutrient supply, soil moisture 

 and light, influence greatly the nature of the response from summer 

 pruning. Consequently it should be employed as an orchard practice 

 only when due consideration is given the several factors on which its 

 results depend. The amateur or the careless grower cannot use it safely. 

 The careful student of fruit growing can often employ it with reasonable 



