26 



Bernbeck, a German investigator, found "that transpiration was pro- 

 portional to the wind rate and to the amount of bending or sw^aying un- 

 dergone by plant structures and that the excessive loss of water ceased 

 when bending w^as eliminated." Experiments to prove the statements are 

 quoted in Geneva Bulletin 23, page 55. The experiments quoted also indi- 

 cate "That rigidity seems to afford total immunity from wind injuries, 

 while sw^aying or bending results in injury." 



From the above observations I draw the following conclusions: 

 I. Kxposure to the prevailing wind and the direct ra^^s of the sun are fac- 

 tors of more importance in this section in preventing bark splitting 

 thaai are cultivation and cover crops. Only trees on southern exposures 

 are affected. The remedy then is apparently to use a northern exposure, 

 or if thiis is not available at least a level field, and then to protect from 

 the wind and sun still more by heading as low as possible. 



WINDBREAKS. 



Wrapping the tree trunks with building paper or wood veneer in ear- 

 ly w^inter should give some protection. 



In early February as soon as the first splits w^ere noticed about thir- 

 ty five trees w^ere carefully wrapped with building paper, the paper being 

 cut in strips about six inches wide, u-rapped round the trees, and tied 

 just below the branches. Thirteen of these protection papers were re- 

 moved yesterday, March 26th, and in no case where the tree was 

 undlamaged \vhen the paper w^as applied u^as injury noted. One or tNvo 

 trees that were badly damaged when the papers were put on showed 

 still further damage but the wounds were comparatively clean and white. 

 What further injury will occur or what effect the present injuries ^vill 

 have on the health and vigor of the trees I am not prepared to say, but 

 the trees are being examined regularly and a careful report will be made 

 later. 



The usual treatment for such wounds Avill be applied in early spring, 

 that is, all loose, dead bark w^ill be removed and the wound covered with 

 grafting w^ax. 



The injuries I have mentioned! I believe to be the primary cause of 

 the development of Black Rot Canke and Crown Rot in apple trees, and 

 consequently only by the prevention or careful treatment oi them can 

 these two serious forms of disease be controlled. 



