N. H. Agricultural Experiment Station [Bulletin 257 



Expected Normal Yield 



The expected normal yield is taken from a smoothed-out curve for 

 yield covering the entire life cycle of the tree. There are, perliaps. 

 too few data upon which to base such a curve. Those obtained in lliis 

 study proved not to be satisfactory owing to the fact that in prac- 

 ticall}^ all blocks trees were of mixed ages ; and even where this was 

 not the case, the growers in the rush of harvest were not able to keep 

 separate records on the yield from different orchards. From various 

 experimental orchards in New Hampshire in which accurate data on 

 yield had been kept for from 10 to 20 years, it appeared that on the 

 average an annual yield of six packed boxes from a mature tree 35 to 

 40 years of age is about all that can ordinarily be expected. This 

 checks reasonably well with data from surveys conducted in other or- 

 chard sections in the eastern part of the United States. Thus, the 

 results of the survey in New York^ suggest an average of about six 



YlElO t 



BOKfo 



' 



AOF IN Y[^RS 



Fig. 2. Expected normal yield 

 This indicates the number of packed boxes that the average orchardist grow- 

 ing chiefly Baldwin and Mcintosh under usual conditions in southern New 

 Hampshire may hope to harvest at each age throughout the life cycle of the 

 tree. A curve calculated by a modification of Reed and Holland's formula 

 for growth rate in plants was fitted to the available data on yield at different 

 ages (dotted line). Empirical deviations from the calculated curve as shown 

 in the solid line seemed necessary. According to this curve, the orchards 

 included in this study should have produced 10.5,000 boxes during the 3-year 

 period. Actually 115,000 boxes were marketed. Since comparatively few 

 bearing trees more than 20 years of age are included in the study, this 

 comparison is mainly a check on the production of young trees. 



bushels per mature tree. The average yield on 441 orchards in the 

 Cumberland-Shenandoah region- was 1.2 barrels per tree, and since 

 many of tlie trees were not matuiv it socmus likely that the average yield 

 of full grown trees would be about six busiiels per year. 



IG. P. Scoville and T. E. LaMont. Apple varieties: Prices, yields, and 

 acreages. Cornell Agr. Exp. Sta. Bull. 495. 1929. 



~C. R. Swinson et. al. Factors influencing the yield of apples in the 

 Cumberland-Shenandoah region. . . . U. S. D. A. Tech. Bull. 54. 1927. 



