New York AGricuLTuRAL EXPERIMENT STATION. oak 
cankers of fruit trees may be at least partially if not wholly 
due to low temperatures. The fact that in some cases a large 
number of successful wound-inoculations were made does not 
preclude it, because that only argues for a wound-parasite. 
Probably some of these organisms can extend a canker wound, 
and to some extent determine its final characteristics, but it is 
certainly a striking fact that practically all such cankers 
attributed to parasitic organisms are located at frost-suscep- 
tible places and generally active but one year. It appears at 
least equally probable that such cankers are due to the death 
of certain tissues, as was shown by Sorauer. These canker 
organisms are confined largely to the bark, and yet it is often 
stated that girdled branches die from their activities. It may 
well be that a short girdle of bark removed from a healthy 
fruit-tree branch would not kill it, for R. Hartig* says that 
after removing six-foot girdles of cortex from fifteen -120-year- 
old Scotch pines, he found some still alive six years later; and 
on girdling 27 species of trees, F. F. R. Channer*? observed 
that five species died, ten others were much injured, while 
twelve species lived. At any rate, it seems plausible that a 
girdled apple-tree branch may die because of its frost-injured 
wood rather than on account of the organisms present in its 
dead girdle of bark. Finding discolored heart-wood at some 
distance from a canker on an apple-tree branch does not neces- 
sarily mean that the canker fungus discolored it, as inter- 
preted by Hasselbring, for it more likely signifies that the tree 
was winter-injured. 
Some cherry-tree diseases.—In referring again to the above 
review of Sorauer’s article, it is seen that the origin-point of 
branches and spurs of cherry are the first parts to be injured 
by low temperature and that in the sour cherry the lumina 
of the conducting vessels had become clogged with gum. In 

“Diseases of Trees. Translated by Sommerville and Ward. P. 249. 
1894. 
*% Indian Forester, 31: 376-8 (1905); abs. in Eapt. Sta. Record, 17: 
670. 1906. See also “ Effects of annular decortication on peaches” by 
F. Calzolari and Manaresi, Eap. Sta. Rec. 21: 439. 1909. 
11 
