no EXPERIMENT STATION. [Jan. 



FROST CRACKS. 



G. E. STONE. 



Many trees of diiferent varieties are subject to frost cracks. 

 These often remain open for several years, and so far as our 

 observations go are almost always to be found on the sunny side 

 of the tree, generally towards the south. They occur in winter, 

 and it is generally believed that they are caused by sudden 

 changes in temperature, and especially by very severe cold. 

 They were very common in this section during the remarkably 

 cold winter of 1903-04, when some fruit trees, 8 or 10 inches 

 in diameter, had frost cracks which opened 4 or 5 inches wide. 



In this section the elm tree is more liable to cracks from the 

 action of frost than other varieties. These are often 12 or 15 

 feet long, and give rise to more or less serious bleeding during 

 the summer months. Cracks in trees occur not infrequently 

 from other causes, such as the splitting of limbs, and wo have 

 known a number of sugar maples to gradually bleed to death 

 from the loss of sap. 



Frost cracks open in winter when the temperature is low, and 

 close in summer. When not very large they sometimes heal over 

 and disappear through the activities of callus growths, but more 

 often they jwrsist for some years, and an extensive opening of 

 the cavity prevents permanent healing, making the tree subject 

 to bleeding in summer. 



Frost cracks are difficult to treat satisfactorily by tree surgery 

 methods, as they often extend quite deeply into the wood, and 

 the orifice is constantly changing in width owing to changes in 

 the temperature. For the same reason certain other cavities in 

 trees are hard to treat, as they sometimes open in winter and 

 allow w%ater to enter, which often results in the displacement of 

 the cement fillings. To obviate this difliculty we have experi- 

 mented largely with elastic cement applied to the edge of the 



