PRUNING BEARING APPLE TREES 9 



Effect of Pruning on Yield 



The number of trees in Block A is too small to furnish very dependable data 

 on yield, but they do show some things that are believed to be significant. The 

 total yields of the several varieties for the four years 1927 to 1930 inclusive are 

 shown in Table 5. 



Table 5. — The effect of pruning on total yields — Block A, 1927 to 1930, 



inclusive. 



(Pounds per tree) 



The yields are small, for this orchard did not produce a full crop until 1933. 

 The total yields of three of these groups for the years 1924 to 1933, are shown 

 in Table 6. 



Table 6. — The effect of pruning on total yields — Block A, 1924 to 1933, 



inclusive.* 



(Pounds per tree) 



*Omitting 1926 and 1932, for which there are no records 



The figures in Table 5 show that the trees which had been headed back in 

 their early years had not recovered and the yields are low. That this handicap was 

 largely overcome in later years is indicated in Table 6. The larger yields of the 

 unpruned Northern Spy trees may have some significance, for other observations 

 have suggested that pruning this variety decreases yields. This is interesting in 

 view of the fact that Spy makes a notably thick top. Perhaps the bearing habit 

 of Northern Spy is involved. There is no conclusive evidence in these tables 

 that pruning has had any great influence on quantity production, provided that 

 heading back the new shoots is not practiced. 



