THE BIRCHES 



197 





AREA OF BIRCH GROWTH 



the silver birch. A little later in life the bark becomes 

 tinged with yellow and the surface is broken in long 

 lines and rolls back in a ragged fringe. Large trunks, 

 especially near the base, lose most of the tattered silvery- 

 yellow bark, becoming dark gray or reddish, and rough- 

 ened by deep, irregular furrows and thick plates. The 

 bark of the twigs has a slight wintergreen odor and a 

 bitter taste. The bark burns very readily when dry and 

 is often used for starting camp fires. Dead yellow birch 

 trees are a danger in case of forest fires, because the 

 fire flashes along the shaggy bark to the top of old stubs, 

 and if a high wind is blowing, pieces of flaming bark 

 are carried long distances ahead of the fire to start a 

 new blaze. 



River birch (Betula nigra), frequently called red, blue, 

 black or water birch, is a medium-sized tree, 30 to 50 

 feet high and 1 to 2 feet in diameter, but occasionally 

 reaching a height of 100 feet and a diameter of 5 feet. 

 As its name indicates, it is found along streams and 

 on other moist soils. Nature uses this tree as a dyke- 

 builder, as the matted roots hold the soil deposited along 

 stream banks by floods. It is sometimes planted to pre- 

 vent stream banks from washing away. 



River birch is native from Massachusetts to Florida 

 and west to Minnesota, Kansas and Texas. The bark is 

 even more ragged than yellow birch, and, like the latter, 

 the outer layers peel off in lustrous, silky scales. The 

 delicate pink-brown or chocolate color of the bark sepa- 

 rates it easily from all other birches. The twigs are 

 red and shining, and are especially graceful as they 

 droop beneath the heavy masses of dark green foliage. 



Western birch (Betula occidentalism is a tree 100 to 

 120 feet high, 3 or 4 feet in diameter, that grows very 

 sparingly in northwestern Washington and southwestern 

 British Columbia. 



Kenai birch (Betula kenaica) is a small tree found 

 only on the coast of Alaska. 



Mountain birch (Betula fontinalis), as its name im- 

 plies, is a mountain species. It is a small tree, or more 

 often a shrub, growing from British Columbia to Colo- 

 rado and west to the Sierra Nevada Mountains of cen- 

 tral California. 



Alaskan white birch (Betula alaskana) is also a small- 

 sized tree. It resembles paper birch and in portions of 

 Alaska it is quite abundant on sunny slopes. It grows 

 from the Saskatchewan valley to the valley of the Yukon 

 River. 



The different species of birch have a number of points 

 in common. The bark has peculiar horizontal markings 

 due to the lengthening of the breathing pores as the tree 

 grows in diameter. The buds are small, pointed, and cov- 

 ered by overlapping scales of various shades of brown. 

 They stand singly and have an alternate arrangement 

 on the stem. The leaves of all species are very much 

 alike in appearance and occur singly or in pairs, but 

 never stand opposite each other. They resemble an 



WHITE OR PAPER BIRCH 



Tangential or bastard cut, the 

 common method of sawing this 

 species of wood. 



Radial cut (quarter sawn). The 

 pitch rays are quite inconspicU' 

 ous in the wood because 

 their small size. 



of 



arrowhead in shape and have saw-toothed edges. The 

 pollen-producing and seed-forming flowers are borne on 

 different parts of the same tree. They appear in early 

 spring before or with the leaves. The pollen-producing 

 flowers are long, tassel-like bodies with a yellow or brown 

 tinge, and hang down from the ends of the twigs. The 

 greenish seed-forming flowers appear below those that 

 produce the pollen and are rather small and slender, 

 standing nearly erect. The fruit is a narrow cone- 

 like structure one-half to three inches long. The scales 

 which compose the fruit bear tiny, flattened chestnut- 

 brown nuts. These nuts are provided with two small, 



