New York Agkicultueal Experiment Statiost. 299 



Nordlinger* discusses some of the effects of a cold snap which oc- 

 curred during the first week in September, 1877; he finds that the 

 bark of many young trees was injured and on others shoots were 

 killed back. In the spring of 1878 fungi appeared on the killed bark 

 and the shoots. Injuries were evident in spring as brownish red 

 spots, especially around the bases of twigs and spurs. Some shoots 

 were discolored only on the sunward sides. 



Nordlinger concludes that vegetative activities must continue later 

 at the bases of shoots and twigs, perhaps owing to the presence of 

 the food materials usually stored in such places. Most of the shoots 

 that had been severely injured at their bases subsequently died. On 

 older structures the injurious effects were usually proportional to the 

 size of the injured areas. 



He holds that R. Hartig's contention that such crotch-cankers are 

 due to spring frosts is erroneous, as may be seen by the examination 

 of cross-sections and also on account of the fact that thousands of 

 cases occur high up in trees and in locations where spring frosts could 

 not have been harmful. He thinks it more likely that the tissues 

 of such injured places entered winter in an immature condition and 

 were injured on that account. 



In a brief note in the Gardener's Chronicle signed by A. D.- it is 

 stated that in December, 1887, a few old plants of Japanese chrys- 

 anthemum were found having the bark loosened on their stems, 

 above the ground. The growth of the plants had been checked by 

 drought and they grew again in fall. The bark was thought to have 

 been loosened by hoarfrost fractures. 



The measurements of tree trunks made at different temperatures 

 during last winter and spring confirm Caspary's observations in 

 showing that the lowering of temperature decreases and the raising 

 of temperature increases the circumference considerably. From a 

 few experiments done last winter with cross-section of large maple 

 branches and trunks of apple trees it was found that the circum- 

 ference of isolated rings of bark decreases appreciably more than that 

 of the cylinders of wood when subjected to the same low temperature 

 and would thus apparently lead to an increase in bark tension. 



It is a well known fact first clearly set forth by Sachs in his Experi- 

 mental Physiologie that tensions between different kinds of tissues 

 result from differences in their rates of growth. The existence of 

 tensions between the bark and wood of a fruit tree can be readily 

 demonstrated by slitting the bark. This method may be used to 

 show that there is often quite a variation in bark tension of different 

 trees as well as at different heights on the same tree. 



' Nordlinger. Die September-Froste 1877 und der Astwurzelschaden (Astwurzel- 

 krebs) an Baumen. 



Centbl. Gesam. Forslw. 4:489-90. 1878. 

 ^ A. D. Effects of recent frosts. 



Gard. Chron. 2:691. 1887. 



