WINTER INJURY 



280 



" . . . If we take the average of buds started on twigs taken 

 December 22, or later, that is, when the resting period is nearly ended, we 

 have ; — 



For trees making large growth (cut back) 28.3 per cent, started. 



For trees making smaller growth (not cut back) 48.6 per cent, started. 



"Taking only those varieties in which one tree had 60 per cent 

 of the buds started, and therefore may be considered to have finished its 

 resting period, we have as an average — 



On trees making large growth (cut back) 44.3 per cent, of the buds 

 started; 



On trees making smaller growth (not cut back) 83.4 per cent, of the 

 buds started." 



It is apparent that the more favorable the conditions become for 

 breaking of the rest period the more evident becomes the restraining 

 influence of late maturity. 



That this retardation of development by pruning actually results in 

 lessening winter injury of the type under discussion is shown by numerous 

 instances cited by Chandler. After a succession of warm days followed 

 by a fall to — 3°F., which would hardly kill any considerable number of 

 buds unless they had started into development, a count was made of 

 dead buds on pruned and unpruned trees. Table 30, arranged from 

 Chandler's data, shows one instance. Even more striking is his enumera- 

 tion of results at Brandsville, Missouri, following the freeze of Mar. 16, 

 1911, when 98.08 per cent, of the buds on unpruned trees were killed 

 while only 81.9 per cent, were killed on the severely pruned trees. ^* The 



T.\BLE 30. — Buds Ivjlled at — 3°F. on Pruned and Unpruned Trees'^ 



Variety 



Per cent, killed 



Pruned 



Unpruned 



Elberta 



Oldmixon Free 



Triumph 



Lewis 



Early Tillotson 



Average 



48.5 

 62.9 

 30.0 

 16.0 

 23.9 



36.2 



67.8 

 78.0 

 59.1 

 25.7 

 .54.7 



59.8 



killing on the pruned trees seems high but 18.1 per cent, of peach buds 

 may produce a full crop, as they did in this instance, while the unpruned 

 trees bore only a few peaches. 



Fertilization and Cultivation. — Nitrogenous fertilizers, stimulating 

 vegetative growth, have much the same effect as pruning, according to 



