18 



N, H. Agricultural Experiment Station [Bulletin 257 



Witli the mature tree the value of pruning is more largely a sub- 

 ject of controversy than with the young tree. It would be expected, 

 since pruning results in more vigorous growtli of shoots and fruit 

 spurs, that even although it- may reduce the ])earing area it might not 

 lower the productivity of the tree or might in some circumstances even 

 increase it. There is, however, but meager data to support this point 

 of view; and in some experiments, notably those conducted in Michi- 

 gan, the pruning of mature trees seems to have resulted in a financial 

 loss bv reduction of vield. ' 



5 6 7 



Farm Number 



Fig. 6. Man hours required by each operator to prune the unit of 1,000 



mature trees 

 Opinions vary as to type and amount of pruning' necessary. Within these 

 rather limited observations, quantity and quality of fruit was not materially 

 improved by spending the maximum time on this operation. Detailed prun- 

 ing- although- desirable from the point of view of the plant physiologist does 

 not appear to result in definitely better returns. 



Pruning is more or less of a thinning operation, and apples from 

 I)i"uned trees will undoubtedly be larger than tliose from trees not 

 pi'uiied. Whether the I'cduction in total crop will be so serious as to 

 offset this ))enefit may depend upon the local market situation which 

 affects the value on the tree of apples of different sizes and grades. 

 If under some circumstances the pruned and unpruned trees were 

 to bear the same number of bushels of good-sized fmit. whicli in the 

 case of the unpruned tree is mixed with a large proportion of under- 

 sized apples, the cost of separating the latter out might be greater 

 than the actual value on the ti-ee of tlie extra ([uantity of small apples. 



The value of certain opei'ations in pruning mature trees cannot he 

 questioned. Branches wliicii bear small apples exclusively can often 



iRoy E. Marshall — Profit and loss in pruning mature apple trees. 

 Michigan Special Bulletin 169, 1928. 



