WINTER INJURY 269 



such buds with their scales. This work was done with 

 peaches only, and they were treated on different dates from 

 February 26 to March 12. The temperature was reduced 

 to various points from — 10° C. to —22.5° C. with the follow- 

 ing average results: 



Total number of buds, scales off, 4430, 51.0 per cent 

 killed; total number of buds, scales on, 5078, 68.5 per cent 

 killed. 



238. Relation of crop the preceding season. — It has been 

 observed in various sections of the country that trees which 

 fruit heaviest are most likely to be injured by very low 

 temperatures the winter immediately following. This ob- 

 servation was repeatedly reported after the severe winter 

 of 1917-18. 



Macoun describes a row of Wealthy apple trees (21 years 

 old) at Ottawa that behaved in this way. Of fourteen trees, 

 the eight which bore a medium to heavy crop in 1917 were 

 killed or badly injured, while the six bearing either a light 

 crop or none at all came through the winter in good condi- 

 tion.^ 



In New York state and in New England it was noted that 

 hardy varieties of the apple were killed more readily than 

 such tender sorts as the Baldwin, if the former had set a 

 heavy crop the preceding season while the latter had 

 not. 



This result was earlier indicated when it was shown that 

 well thinned peach trees seemed to be more resistant than 

 unthinned ones which bore a heavy crop: ^ average per- 

 centage of peach buds killed, tree thinned, 35.4; average 

 percentage of peach buds killed, trees not thinned, 51.4. 



239. Correlation of wood structure and hardiness. — 

 Various attempts have been made to discover any correla- 



1 Proc. Amer. Soc. Hort. Sci. 1918. p. 17. 

 ^ Mo. Agr. Exp. Sta. Bull. 74. 1907. 



