258 



PRINCIPLES AND PRACTICE OF PRUNING 



during winter. Such pruning aids in thinning the fruit 

 (106), but does not wholly obviate summer thinning. 

 Always the aim should be to keep the trees low-headed, 

 so as much fruit as possible may be gathered without the 

 aid of ladders, and when ladders are used at all they 

 should be not more than 6 feet high. 



202. Pruning vs. peach bud vigor. W. H. Chandler* experimented 

 with peach trees to determine the effect of pruning and trimming 

 upon bud vigor. His main conclusions follow : 



In Missouri nearly every winter warm weather starts the buds 

 into growth more or less. Fruit buds on trees that have made a 

 vigorous growth, caused by reasonably 

 severe heading back or by cultivation, are 

 the less liable to winter injury. Heading 

 back may be too severe, however, since 

 in any year the fruit buds most likely to 

 come through the winter safely are those 

 at the base of the whips of new wood. I f 

 the heading back has been too severe, tl e 

 growth will be so dense that no fruit buds 

 will be formed at the base of those whips. 

 In the experiment station orchard the 

 trees having the smallest percentage of 

 buds killed were those trained to a 

 spreading, open head, and forced by prun- 

 ing and cultivation to make a vigorous 

 growth. 



The fruit on trees with spreading he-id-* 

 does not rot so badly as that on trees with 

 dense heads. The fruit on trees making 

 a vigorous growth, unless the gro \vtli is 

 too vigorous, is larger than that on trees 

 making smaller growth. This is true ex- 

 cept with early varieties, where a tree making a rather small wood 

 growth bears the better fruit. 



Thinning the fruit enables the tree to set more hardy fruit buds 

 for the next crop [than where it is not practiced]. In the station 

 orchard a temperature of 6 degrees below zero one winter killed 

 from 5 to 40 per cent more buds on the unthinned side of a tree 

 than on the thinned side. 



In experiments conducted bv F. A. Waugh in Massachusetts, 

 peach trees left unpruned for nine years became open headed and 

 of vase form, but the lower parts of the branches were bare and 

 the fruiting wood sparse, weak and high up in the trees. The trees 

 were also much less vigorous than pruned trees of the same variety : 



FIG. 220 PROPERLY CUT 



BACK PEACH 

 This five-year tree had 

 been severely winter injured. 

 It was saved by radical cut- 

 ting. 



* Missouri Experiment Station Bulletin 74. 



