CHAPTER XXII 

 PRUNING— THE AMOUNT OR SEVERITY 



Pruning can vary in three major respects and in three only. It can 

 vary: (1) in amount or severity, (2) in kind or distribution and (3) in the 

 season at which it is done. Characteristic responses by the plant are 

 to be expected not only as the pruning varies in any of these three respects 

 but according to fruiting habit and as the plant itself varies in age, vigor 

 and nutritive condition. These three major aspects of pruning are dis- 

 cussed in the order in which they have been mentioned. 



A search through horticultural literature reveals a great diversity of 

 opinion as to the influence of varying amounts of pruning on growth and 

 productiveness. Some have considered heavy pruning a great stimulant 

 to vegetate growth especially, though perhaps having the opposite effect 

 on fruit production. This idea is reflected in the phrase "prune in the 

 winter for wood." Others have regarded pruning of any kind and more 

 particularly, pruning in any amount, as a harmful practice because it has 

 been thought to check growth. Most of these partly accepted ideas have 

 been based upon theoretical considerations or field observations, of which 

 some have been sound and accurate but many have been either fallacious 

 or inaccurate or have failed to consider other important facts. Not until 

 comparatively recent years have exact and pertinent experimental data 

 been available. 



Influence on Size of Tree. — Bedford and Pickering^ were among the 

 first to make a careful study of the different effects of various amounts of 

 dormant season pruning on the apple. Table 1 shows the mean tree 

 size and weight for all varieties studied and given different pruning treat- 

 ments covering a period of ten years. The figures for tree size take into 

 consideration spread and height and trunk circumference. Clearly these 

 show that the unpruned tree increases in size and weight more rapidly 



Table 1. — Influence of Amount of Pruning on Tree Size in the Apple 



(After Bedford and Pickering*) 



Very Little or no Pruning Moderate Pruning Hard Pruning 



Tree size relative. . 106 100 82 



Tree weight relativel20 100 84 



than the pruned tree and that the heavier the pruning the more pro- 

 nounced is the check upon growth. In commenting on the somewhat 

 greater influence of pruning on weight than on size revealed by the figures 

 in the table Bedford and Pickering remark, ''This increase in weight 

 must be due to an increase in weight of the stem and main branches, for it 



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