APPENDIX. 459 



hundred and forty feet high, by six feet or more in diameter. The bai'k o» 

 the young tree is smooth and light grayish green in color, but on the 

 mature tree it becomes rough seamed and gray. The wood is much superior 

 to that of the aspen for all economic purposes. 



Range — California to the Arctic Circle, and eastward to the Atlantic 

 States and Canada. 



Use — Excelsior, paper pulp, rails and fuel. On the Yukon and Pelly 

 rivers it is much used for canoes by the Indians. 



BLACK COTTONWOOD. 

 {P. Irichocarpa T. <fc G.) 



This tree is much more limited in regional range than either of the tw© 

 preceding, liut has about the same altitudinal range as the balsam poplar. 

 It favors moist, rich stream banks, where it frequently attains a height of 

 one hundred and twenty feet or more by about six feet in diameter. In 

 bark, size, and general appearance it resembles the balsam poplar much 

 more than the aspen, and the wood is fully equal to that of the former for 

 economic use. 



Range — California to British Columbia. 



Use — Excelsior, paper ])ul]). rails, and fuel. 



WESTERN BIRCH. 

 {Betula occidentalis Hook.^ 



The western birch is mostly confined to valleys east of the Cascade Range, 

 not because of any lack of favorable conditions of growth on the west side 

 but chiefly owing to the more rapid and luxurant growth of the conifei*s 

 crowding it out of the forest there. Under favorable conditions it attains a 

 height of ninety feet and a basal diameter of one and one-half to two feet. 

 The bark varies so much in color ( all the way from a whitish-gray to a 

 dark-brown) that the tree is sometimes called "White Birch," "Black 

 Birch," etc. The wood is dark, close grained, takes a high polish, and is 

 valued for certain kinds of cabinetwork. 



Range — California to British Columbia and eastward to Edmonton. 

 Alberta. 



Use — Furniture, cabinetwork, and, when young, for barrel hoops. 



MOUNTAIN ALDER 

 {Alnus rhombifolia Nutt.) 



A much smaller tree than the red alder, ranging from twelve to fifty feet 

 in height and from six to eighteen inches in basal diameter. It has a more 

 restricted regional range but a greater altitudinal range than the latter. 



Range — California to British Columbia and eastward to the Selkirks. 

 ITse — Furniture, fuel, etc. 



RED ALDER. 



{Alnus Oregona Nutt.) 



The alder is commonly supposed to be a small tree or shrub, but this one 

 is a notable exception, and in a favorable habitat attains a height of one 



