-15- 



Table 1. Variables influencing apple tree size and tree spacings and examples of 

 the effects of these variables. 



Variable or Variables Example of effect of variable 



Soil 1. In an experiment with young Mcintosh trees on 10 dif- 



ferent soils, tree size differs as much as 50% among 

 sites. 



Rootstock 1. Mcintosh on M7A may be 55-75% as large as when on a 



seedling tree. 



Tree training l<t soil 1. Mature Red Prince Delicious trees on M26 rootstock in 



one orchard averaged 15.7 feet in height and 17.2 

 feet in spread. In another orchard, trees of the 

 same cultivar and on the same rootstock averaged 8.5 

 feet in height and 10 feet in spread. 



Cultivar 1. Mature Cortland and Golden Delicious trees on M7 



prior to dormant pruning averaged 23.6 ft and 16.8 ft 

 in spread, respectively. 



Strain 1. Mature non-spur Delicious and spur Delicious on M7 



prior to dormant pruning averaged 21 feet and 15 feet 

 in spread, respectively. 

 2. Mature Macspur and Rogers Mcintosh on M7 had similar 

 tree spread because of variability among Macspur. 

 "True" Macspur had 3 feet less spread than Rogers 

 Mcintosh. 



Strain/rootstock 1. There is less difference in tree size between a spur 



and non-spur strain of the same cultivar when they 

 are on weaker rootstocks than when they are on 

 stronger rootstocks. 



Pruning 1. Red Prince Delicious trees on MM106 spaced 14 feet x 



22 feet began to crowd badly in their 7th growing 

 season. Because of the grower's willingness to do 

 corrective pruning, no tree removal has been 

 necessary through 14 growing seasons. 

 2. Red Prince Delicious on M26 rootstock, planted in 

 1972, are being maintained at 8 feet by 22 feet 

 spacing by corrective pruning. Trees in the same 

 block spaced 16 feet by 22 feet have a 17 foot 

 spread. 



Pruning and equipment 1. Mature non-spur Delicious trees on seedling roots 



spaced 18 feet by 20 feet are being maintained with 

 no tree removal because of corrective pruning and 

 smaller equipment. 



