Summer pruning has been suggested as a technique for devital- 

 izing trees in crowded plantings. The overall growth of the 

 Cortland trees, as indicated by trunk circumference increase, was 

 reduced by summer pruning (Table 2). Nevertheless, terminal growth 

 the year following summer pruning was greater than on the dormant- 

 pruned trees (Table 2) . The Red Prince Delicious trees also were 

 not devitalized by summer pruning (Table 1} . The only consistent 

 beneficial effect of summer pruning was improved red color of 

 Mcintosh apples from trees receiving the dormant- type , mechanical 

 hedging, or the cutting to the first fruiting spur summer pruning 

 treatments (Table 3). 



When large branches were thinned or stubbed in the top of the 

 Mcintosh trees in early August (Treatments 2 and 5) they caused 

 bruising and drop of some fruit on lower branches as they fell. 

 This could have been avoided by stubbing or thinning large branches 

 during dormant pruning. Otherwise, the dormant-type pruning treat- 

 ment on Mcintosh, the treatment of restricting growth in the upper 

 third of Mcintosh and the summer pruning procedures on Red Prince 

 Delicious were not particularly troublesome or time consuming. 

 These procedures could provide work for employees experienced in 

 pruning during the slo\v season, in some orchards, prior to harvest. 

 Cutting all current season's shoots on Mcintosh and the summer 

 pruning methods on the Cortland trees were most time-consuming of 

 the summer pruning practices. Hov;ever, tliese procedures could be 

 performed by labor inexperienced in pruning. Hedging performed 

 by a mechanical device would be the least time consuming of the 

 summer procedures followed. Emerson and Hayden in Indiana reported 

 that in comparison to normal winter pruning, summer hedging every 

 year plus dormant pruning every third or fourth year, reduced prun- 

 ing costs, increased fruit color, and maintained good yields. 



Other researchers besides the authors have reported that 

 summer pruning failed to suppress terminal growth. Nevertheless, 

 it is difficult to explain why cutting to the first fruit on the 

 Mcintosh and Cortland trees failed to increase fruit calcium (Ca) . 

 In an earlier study at the Horticultural Research Center in 

 Belchertown, MA, Drake and Bramlage reported that the removal of 

 all current-year shoots improved fruit Ca levels and fruit quality. 

 However, it does seem reasonable to assume that the magnitude of 

 responses to summer pruning depends on tree vigor and the amount 

 of leaf surface removed. The responses may develop more quickly 

 with precocious varieties on the more dwarfing rootstocks. It 

 is possible that Drake and Bramlage and others who have reported 

 an improvement in fruit quality following summer pruning removed 

 a much higher proportion of the total leaf surface than in present 

 study. Also the effects may be cumulative, thus the responses to 

 summer pruning of trees on seedling roots or vigorous size-control- 

 ling rootstocks may be slow to develop except in situations where 

 a larger percentage of the leaf area is removed. 



