EXOGENOUS SERIESBROADLEAF WOODS. 77 



Paper Birch, White Birch. Betula papyrifera Marsh. 



Nomenclature. (Sudworth.) 



Paper Birch, White Birch Boleau (Quebec). 



(local and common names). Canoe Birch (Me.,Vt., N. EL, 

 Silver Birch (Minn.). R. I., Mass., N. Y., Pa., 



Large White Birch (Vt.). Wis., Mich., Minn.). 



Locality. 



Northern United States, northward into Canada, valley of the 

 Yukon in Alaska. 



Features of Tree. 



Fifty to seventy feet in height, one and one-half to two and 

 one-half feet in diameter. Smooth white exterior bark on 

 large limbs and trunks away from ground. Brown or orange 

 inner surfaces of bark. Splits freely into thin paper-like 

 layers. 



Color, Grain, or Appearance of Wood. 



Heartwood brown tinged with red, sapwood nearly white. 

 Very close-grained, compact structure. 



Structural Qualities of Wood. 



Strong, hard, tough, not durable. 



Representative Uses of Wood. 



Spools, shoe-lasts, pegs, paper-pulp, fuel, bark used in canoes. 



Weight of Seasoned Wood in Pounds per Cubic Foot. 



37- 

 Modulus of Elasticity. 



1,850,000. 

 Modulus of Rupture. 



15,000. 



Remarks. 



Starch is said to be manufactured from inner bark by Northern 

 Indians. Reaches higher latitude than any American decid- 

 uous tree. Forms forests. The name White Birch is because 

 of the color of the bark. Used for pill boxes. One of the 

 few woods that burn well while green. 



