Spruce and Fir 



125 



look so much alike that it is difficult to tell them apart 

 at a distance. But the bark of the fir, except on old 

 trunks, is quite smooth, and on its surface are numerous 

 blisters of a resinous substance called " balsam." These 

 blisters distinguish the true firs from all other trees. 

 The balsam which is obtained from the balsam fir is 

 called " Canada balsam." It is used in fixing delicate 

 specimens on glass slides for examination through a 

 compound microscope. " Pine pillows," filled with the 

 leaves of this tree, keep their fragrance for 2 or 3 years. 



In the mountains of Tennessee, North Carolina, and 

 Virginia a different species called " Eraser's fir " is 

 found, and other large species of fir from which valuable 

 lumber is obtained grow in the mountains of our Western 

 states. Although abun- 

 dant in the woods in 

 cold regions, firs are not 

 seen in cultivation as 

 often as spruces. 



The Douglas fir. The 

 Douglas fir is also called 

 "Douglas spruce," 

 though it is neither a 

 fir nor a spruce, but 

 only a close relative of 

 these trees. It is one 

 of the most valuable 

 trees of the whole 

 country. It is widely 



. R. E. Horsey 



distributed in the ,, ~ . . , . , . 



FIG. 82. Douglas fir, Highland Park, 

 mountains Of the West Rochester, New York. 



