- 24 - 



were $10.00, $5.00, and $2.30, respectively. Obviously, dramatic differences 

 exist between the newly planted trees and the standard trees as to the 

 distribution of fruit into grades, but to simplify the model the proportions were 

 held constant and the differences were accounted for with yield differences. 



Total cost for each strain-rootstock combination was the summation of the 

 following costs: site preparation, planting, nonbearing growing years 1 through 

 3, bearing growing years 4 through 20, harvesting, cooling, and storage. All 

 costs were figured on a per acre basis using current prices. 



For the 20-year life span of the rejuvenated orchard, costs and revenues 

 were totaled and returns to management were calculated per acre for all strain- 

 rootstock combinations. An acre planted in year 1 incurred costs of site 

 preparation, planting, and nonbearing maintenance through the first 4 growing 

 years with no revenues received. In year 5, when these trees began to bear 

 fruit, revenues were positive and increased through matarity. Revenues were 

 received from these trees for 16 years. However, an acre planted in year 5 

 earned revenut^s for only 12 of the 20 years. Trees planted in year 10 earned 

 revenues for only 7 years within the framework of this study. 



RESULTS 



The discussion of results is divided between findings of the original set of 

 constraints, called the original modiil, and findings of the modified models 

 resulting when constraints .vere changed to reflect changes in availability of 

 orchard resources. Comments are included about each strain-rootstock 

 combination and about ?ach constraint. 



Results of the Original Model 



Table 1 presents the optimal lO-year plant ing plan for the 50 rejuvenated 

 acres, as determined by the original model. 



Table 1. Planting plan for the original model. 



Planting year Rogers/M.7A Marshall/M.7A Marshall/M.26 Marshall/OARl 



10 5 



2 2.2 2.8 



3 5 



4 3.9 1.1 



5 5 



6 0,1 4.9 



7 5 



8 5 



9 5 

 10 5 



TOTAL 0,1 36 13.9 



