- 3 - 



the basis of equal production per unit of land area utilized, the 

 total lifetime production of the 8' x 16' planting will be about 

 50% greater than a 15' x 30' planting at 30 years of age. There- 

 fore, he concluded that if we can accurately estimate the spacing 

 at which trees can be economically maintained by pruning, and can 

 maintain high yield per square foot of tree-spread for a reason- 

 able lifetime of the tree, great gains in production can be achieved 

 by choosing the proper spacing at planting. 



With a constant alley width, land utilization favors the larg- 

 er tree. For example, with a constant alley of 8', an 8' x 16' 

 planting of trees will eventually occupy 50% of the land, whereas 

 a 32' X 40' planting will occupy 80% of the land at full spread. 



If one assumes equal yield per square foot of space occupied, 

 the larger tree may eventually surpass the smaller trees in produc- 

 tion. However, Cain showed that small trees produce higher yields 

 per foot of space occupied by the trees. When he applied the fac- 

 tor for yield in lbs/ft of tree-spread to the calculation of space 

 occupied at different tree spacings, he concluded that with a con- 

 stant alley-way of 8 feet, the smaller tree properly spaced pro- 

 duces more bushels per acre and reaches maximum production at an 

 earlier age, thereby eliminating the possibility of the larger 

 tree ever exceeding the smaller tree in lifetime production. 



Dr. Cain estimated the efficiency and net return for life- 

 time-average bushels per acre for a 40-year-old orchard at various 

 spacings. Tentative cost values were assigned for the various in- 

 put factors and these costs were converted to bushels of apples so 

 that input and output could be expressed in the same units. His 

 calculations showed the following. "The total input per acre per 

 year is much greater for the smaller trees, but is largely accounted 

 for by the cost of harvesting greater yields. Efficiency (output/ 

 input) is only about 25 per cent greater for the 12' x 20' plant- 

 ing than for the 32' x 40' planting. However, the net gain (out- 

 put-input) for the smaller tree is over 2.5 times that of the 

 large tree. The maximum efficiency and net gain for life-time pro- 

 duction appears to be obtained from a tree about 12 feet wide, but 

 variations in orchard lifetime; weather conditions, and other var- 

 iables of estimate could not justify distinction between tree sizes 

 of 8 to 15 feet. However, there does not appear to be any good 

 reason to plant trees whose final spread is expected to exceed 20 

 feet. " 



the 



With 

 our older recommendation of _ 

 tion of 15' X 25' spaci ng for 



information quoted above in mind, let's re-examine 



20 ' X 30 ' spaci ng and our newer sugges- 

 Mclntosh on EM VII. Some persons 

 are talking about the possibility of restricting tree spread of 

 Mcintosh on EM VII to 6 feet. The question is: Would it have teen 

 possible to restrict spread to 6 feet in the University of Massa- 

 chusetts orchard mentioned above without forcing excessive vegeta- 

 tive growth and without reducing yields? Furthermore, Dr. Cain's 

 calculations indicated no distinct differences between 8 feet and 



