6 



same temperature. Thus,, during the winter of 1917-18, there 

 was much less injury toward the western end of Lake Ontario 

 than in the counties farther east, but still on the lake that 

 should have the same lake protection. Probably, except for 

 the cold night of December .30, the temperatures ran about the 

 same, but on that night there was a cloud hanging over the 

 western end of the lake and the temperature did not go nearly 

 so low. It seems probable, then, that it was on that night 

 that the killing was done farther east. 



Of course, in case of wood, the amount of injury suffered at 

 any temperature is influenced much more largely by the ripe- 

 ness of the w^ood than by anything else. This does not mean 

 that the weakest trees that cease growing earlier are necessarily 

 the ones that suffer the least injury. We shall see from ex- 

 perience in 1917-18 that proper maturity depends upon the 

 presence of a large healthy leaf surface. Then, too, the recovery 

 of the tree does not depend entirely upon the amount of tissue 

 killed. Thus, if two trees of unequal vigor have an equal pro- 

 portion of their wood killed, the more vigorous tree will gen- 

 erally make the better recovery. 



During the summer of 1918 I had an opportunity to study 

 the effects of the preceding severe winter in nearly all sections 

 of New York and in some sections of Canada, Vermont, Massa- 

 chusetts and Indiana. There were many different kinds of 

 injury to be observed, and it seems wise to describe some of the 

 more general ones. 



If a bearing tree were injured but little, what injury there 

 was would generally show by the browning in the sapwood of 

 the spurs. If the injury were greater, this browning was likely 

 to be found in the sapwood in any portion of the tree above 

 the snow line. In the case of Baldwin and Greening, there was 

 often browning in the twigs when the amount of injury back in 

 the branches was not great enough to cause serious harm. On 

 the other hand, with Ben Davis there was often very little 

 browning in the twigs and very much near the base of the 

 branches. When the browning was in the twigs and smaller 

 portion of the branches, the growth in the following spring was 

 very weak, the leaves being much smaller than normal. On 

 the other hand, when the twigs were but slightly injured and the 



