PRUNING— THE AMOUNT OR SEVERITY 



415 



Table 10. — Influence of Pruning on Leaf Size Area 

 (After Alderman and Auchter^) 



I'uf area (s<iuare 

 inches) 



Lupton 

 orchard 



Grimes 

 orchard 



Total leaf area per tree 

 (.square feet) 



Lupton Grimes 



orchard orchard 



Heavy pruning. . . 

 Moderate pruning 

 Light pruning. . . . 



2.77 

 2.37 

 2.10 



4.99 

 4.18 

 3.52 



610.8 

 432.2 

 418.7 



1143.8 

 911.5 

 659.6 



The decrease in size of fruit recorded by Bedford and Pickering* 

 as accompanying severe pruning probably is explained by the increased 

 leaf area of the trees and the consequently greater requirement of this 

 foliage for water — a requirement that under the conditions of the experi- 

 ment the roots were unable to supply. Experience and observation 

 generally indicate that pruning does not decrease size of fruit. As 

 a matter of fact it often has the opposite effect. Perhaps this tendency 

 is most clearly shown in such fruits as the raspberry, blackberry and grape 

 which in the absence of pruning are inclined to set more fruit than they 

 can mature properly, especially when supporting the large amount of 

 barren wood which unpruned plants of these species characteristically 

 bear. Within certain rather wide limits the general influence of pruning 

 is to reduce, through the removal of actual or potential bearing wood, 

 the amount of fruit that can set. It tends also to enlarge leaf area 

 and thus, though its effects are concentrating, it at the same time increases 

 the requirement for nutrients and moisture. If these are available in ample 

 quantities pruning may result in an increase in size of fruit; if they are 

 lacking it may result in a reduction. Though the general tendency of 

 pruning, as of fertilization, is to increase the size of the fruit, its influence 

 in this regard is not direct. Nevertheless it is one of the most important 

 means at the grower's disposal for this purpose. This is particularly 

 true for those species or varieties with which thinning of the fruit is 

 impracticable. 



Pruning as a Cause of Abnormal Structures. — In the sections on 

 Water Relations and Nutrition attention is directed to certain patho- 

 logical conditions that may result from extremes of moisture or from an 

 unbalanced nutrient supply. Pruning may disturb both the water and 

 food relations of the plant; hence certain pathological conditions may 

 follow, particularly from heavy pruning. Daniel,'* who has given this 

 question considerable attention, enumerates a rather large number of 

 monstrosities more or less directly attributable to pruning. Among the 

 more important of these maybe mentioned the forcing out of the so-called 

 "second-bloom" from the limbs and trunks of pear trees, marked 



