THE HEMLOCK, FIR, AND LARCH. 275 



Mountains many of the trees are destroyed solely f or 

 their bark, although the timber is very valuable for 

 house-framing and for rough boarding ; much of it, 

 though, is subject to a flaw called "wind shake," a 

 perpendicular splitting of the wood caused by winter 

 storms which bend and " shake " the stems. The 

 wood is rather white, and faintly tinged with buff 

 or pink ; its grain is coarse, twisted, and unfit for 

 interior finish. 



The mountain hemlock {Tsuga CaroUniana) is 

 a species so similar to the foregoing that it is not 

 an easy matter to discriminate between them. It 

 is rather rare, anyway, growing wild only in the 

 higher Alleghany Mountains. A small specimen ia 

 the Arnold Arboretum, the only one I have seen, 

 differs from the common hemlock in its larger needle 

 more thickly distributed over the branchlet, and its 

 larger cone with more spreading scales. This tree 

 rarely grows over 30 feet high. 



Balsam Fir. The balsam fir is the much-esteemed 

 Aiies baisamea. " Christmas tree," whose aromatic 

 -perfume is a sufficient means for its identification. 

 This is the tree, in fact, which furnishes the needles 

 for "pine pillows." It can not be reasonably con- 

 fused with the spruce for several reasons. Its needle 

 is about three quarters of an inch long (rarely it 

 measures a full inch), dark blue-green above and 



