252 A MANUAL OF FORESTRY. 



Cheimatolia Irumata, and in Central Europe by the 

 blister-beetle, Lytta vesicatoria. The shoots are some- 

 times much stunted by the larvae of a Tineid moth, 

 Prays curtisella. The bark is sought and badly gnawed 

 by the hornet. The Cossidce readily attack it ; Zeuzera 

 preferring the saplings to any other food plant. The 

 bark-beetles, Hylesinus fraxini and crenatus kill sickly 

 trees; the former also attacks the upper branches of 

 healthy trees and kills them in a few years by working 

 down the stem* 



Cancerous spots in the bark may be caused by Nectria 

 ditissima. 



The thinnings of Ash woods should be such as to 

 enable the tree to lay on diameter increment, in other 

 words to give it a liberal growing space at all times, 

 and especially with advancing age. 



5. ELM= Ulmus (L.). 

 The following two species will be noticed here : 



(1.) The Common Elm= Ulmus campestris, Sm. 

 (2.) The Scotch, Wych or Mountain Elm= Ulmus 

 montana, Sm. 



a. Utility. 



Elm yields a coarse timber which is hard, moderately 

 heavy, difficult to split, very durable, even when ex- 

 posed to become alternately wet and dry. Specific 

 gravity of air-dried Common Elm = -69. It is used for a 

 great variety of purposes in rural districts, by the car- 

 penter, joiner, wheelwright, turner, boat-builder, and 

 others. It yields a good firewood, and the leaves are 

 good fodder. The ashes yield excellent potash. 



