PRUNING— THE AMOUNT OR SEVERITY 



409 



cannot be accounted for merely by the weight of wood removed during 

 pruning: the prunings would, on an average, have amounted to 27 

 pounds per tree during the ten years in the case of the moderately pruned 

 trees, whereas these trees at the end of this time showed a deficit of 49 

 pounds as compared with the unpruned ones." Gardner'^ in Oregon and 

 Alderman and Auchter^ in West Virginia (see Table 2), both working 

 with young apple trees, obtained results leading to the same conclusions. 

 The unpruned tree increases in size more rapidly than the moderately 

 or heavily pruned tree, not because it produces more new shoot growth 

 each year, but because it losses none by pruning. Tufts, ^^ in California, 

 studying the influence of varying amounts of pruning on newly set 

 apricots, sweet cherries, peaches, pears and European and Japanese 

 plums found, in every instance, less rapid increases in trunk circumference 

 with each increase in the severity of the pruning (see Table 3). Since 

 he found correlation coefficients ranging from 0.83 to 0.92 for trunk cir- 

 cumferences and weights of top and coefficients ranging from 0.76 to 

 0.84 for trunk circumferences and weights of root, depending on the 

 species, it is evident that trunk circumferences may be taken, other 

 things equal, as fairly accurate indices to tree size. Consequently his 

 data, together with those of the investigators already cited, are evidence 

 that, in general, pruning results in a check to increase in size. At least 

 it may be considered established that this holds for deciduous tree fruits. 



Table 2. 



-Influence of Amount of Pruning on Size of Young Apple Trees 

 (After Alderman and Auchter'^) 



Variety 



Type of 

 pruning 



Number 

 of trees 



Height 

 (in feet) 



Spread 

 (in feet) 



Stayman 



Stayman 



Stayman 



Rome 



Rome 



Rome 



Gravenstein 



Gravenstein 



Gravenstein 



Stark 



Stark 



York, Grimes and Rome 

 York, Grimes and Rome 

 York, Grimes and Rome 



Heavy 



Moderate 



Light 



Heavj' 



Moderate 



Light 



Heavy 



Moderate 



Light 



Heavy 



Light 



Heavy 



Moderate 



Light 



7.32 

 7.89 

 9.50 



7.45 

 8.18 

 9.16 



7.43 

 6.83 

 8.94 



7.57 

 10.79 



9.55 

 9.73 

 10.50 



5.29 

 5.52 

 5.75 



3.68 

 4.17 

 4.23 



4.05 

 4.19 

 4.34 



5.17 

 6.85 



4.83 

 6.17 

 7 10 



