EXOGENOUS SERIES BROADLEAF WOODS. 



79 



Yellow Birch. Betula lutea Michx. f. 



Nomenclature. (Sudworth.) 



Yellow Birch (local and com- Swamp Birch (Minn.). 



mon name). Silver Birch (N. H.). 



Gray Birch (Vt., R. I., Pa., Merisier, Merisier Rouge 



Mich., Minn.). (Quebec). 



American Mahogany. 



Locality. 



Newfoundland to North Carolina, westward intermittently to 

 Minneosta and Texas. Best developed north of the Great 

 Lakes. 



Features of Tree. 



Sixty to eighty feet or more in height, two to four feet in 

 diameter. A medium-sized tree. Bark on trunk silvery gray 

 to silvery yellow, branches green to lustrous or dull brown. 

 Bark exfoliates, causing a rough, ragged appearance. 



Color, Appearance, or Grain of Wood. 



Heartwood light reddish brown, sapwood nearly white, close- 

 grained, compact structure, satiny. 



Structural Qualities of Wood. 



Heavy, very strong, and hard, tough, susceptible of high polish. 

 Qualities suggest those of maple. Not durable when exposed. 



Representative Uses of Wood. 



Furniture, buttons, tassel-moulds, pill-boxes, spools, and 

 wheel-hubs. Chair seats. 



Weight of Seasoned Wood in Pounds per Cubic Foot. 



40. 

 Modulus of Elasticity. 



2,290,000. 

 Modulus of Rupture. 



17,700. 



Remarks. 



Occasional trees have thin outer bark ruptured, and exhibit 

 inner bark of almost metallic yellow. Lutea, signifying 

 yellow, alludes to color of bark. Inner bark has pungent, 

 pleasant flavor. Burls, as frequently found, are valued for 

 making mallets. 



