USES OF COMMERCIAL WOODS. 11 



from beechnuts is substituted for olive oil in Europe, and the kernels 

 are ground for flour and eaten after the oil is extracted. This sug- 

 gests a possible use for the nuts in this country. They are occasion- 

 ally gathered and sold in Canada and in some of the Northern States, 

 but the trade is not large. 



SWEET BIRCH. 



(Betulii lentil.) 



PHYSICAL PROPERTIES. 



WeigJit of dry irooil. — 47.47 iidiukIs jier cubic foot (Sargent). 



Specific gravity. — <).~(M~ ( Sargent ) . 



Ash. — 0.2G per cent of weight of dry wood (Sargent). 



Fuel value. — 102 i>er cent of that of white oak (Sargent). 



Breaking strength (modulus of rupture). — 17.(X)0 pounds per sqnare inch, or 

 136 per cent that of white oak (Sargent). 



Factor of stiffness {moduJus of elasticity). — 2.042.rK¥) ]iounds per sqnare 

 inch, or 152 per cent that of white oak (Sargent). 



Wood heavy, very strong and hard, comimct, satiny, susceptible of a beau- 

 tiful polish: medullary rays numerous, obscure: cojor dark drown, tinged with 

 red. the sapwood light brown or yellow. The peculiar luster of this wood, when 

 well polished, is due to the bright lining of the wood pores. 



Height. 55 to 90 feet : diameter, IJ to 4 feet. 



SUPPLY. 



Sweet birch is found in commercial quantities in half of the States, 

 its range lying chiefly east of the Mississippi River, but crossing a 

 little into Minnesota. Xo cut is reported from Mississippi, Ala- 

 bama, Louisiana, or Illinois, but it comes from all other States in 

 the eastern half of the country. The wood is lumbered in rather 

 small amounts compared with some of the oaks and pines, but is of 

 much importance l^ecause of its excellent qualities. Exact statistics 

 of output are not available because this birch has been grouped with 

 several others in Government reports of lumber operations. The 

 birch sawmill cut in 1009 was 452,000.(X)0 feet. l3ut this included, in 

 addition to sweet birch, yellow birch {Betnla Intea). gray Inrch 

 {Bet Ilia popylifolia)^ paper birch {Betnla pcvpyrifera), river birch 

 (Betnla. nigra), and perhaps some of the less abundant species. 



The sweet birch on the market comes from several widelv sep- 

 arated regions. Xowhere does it form extensive stands. The trees 

 are cut as lumbermen come to them in logging operations among 

 other species, and few^ if any mills saw birch exclusively. Though 

 it is not known what amount of sweet birch still remains, it is 

 probably much under that of l)eech. and certainly less than sugar 

 maple. In 1908 a reconnaissance of the standing timber in Ken- 

 tucky credited that State with 55.000.000 feet of birch, but yellow 

 was included with the sweet. Michigan has been a leader in the 



