﻿18 BULLETIN 12, U. S. DEPARTMENT OF AGRICULTURE. 



BY-PRODUCTS. 



Several by-products are derived from sweet birch. For 200 years 

 white men have made birch beer, and Indians have made it from time 

 immemorial. It is considered a harmless beverage, and is seldom a 

 commercial commodity, but is pretty generally made within the sweet 

 birch's range. The flow of sap from this tree is much more copious 

 than from the sugar maple. 



In early summer the soft layer of new wood just beneath the bark 

 is edible. The taste is peculiar and pleasant. It can not be classed 

 as an important article of food, but trees are often peeled to obtain it. 1 



It is said that the characteristic odor of Russian leather is due to 

 birch oil obtained in America and employed in dressing the product. 



The commercial oil of wintergreen is frequently made of sweet 

 birch. It is not an article of much value from a commercial stand- 

 point, but it is one of considerable interest. About the year 1863 in 

 Luzerne County, Pa., a trade in the genuine oil of Avintergreen 

 (Gaultheria procumbens) came into existence. It was presently dis- 

 covered that sweet birch, by distillation, yielded an oil so nearly like 

 that of wintergreen that only by painstaking chemical analysis could 

 the counterfeit be detected. At first, birch and wintergreen were 

 distilled together in the same vessel, but birch was more easily pro- 

 cured, and it gradually displaced the wintergreen. The industry 

 has continued to the present time in mountainous regions of Pennsyl- 

 vania. West Virginia, Kentucky, and North Carolina, but it has 

 ahvays been carried on after the simplest and most primitive fashion. 

 A ton of chips yields only 2 quarts of oil, which is used to flavor 

 candy and medicines. The oil consists largely of salicylic acid and 

 wood alcohol. It is not unusual for the mountaineers to sacrifice 

 100 or more young birches to make a pint of oil. 



The supply of sweet-birch lumber must decline, for the tree does 

 not grow rapidly, and the best wood is not produced on the rugged 

 mountain sides where the future supply must be sought. The species 

 has not yet appealed to those who are planting for commercial pur- 

 poses, and if planted a long time will be required for trees to grow 

 large enough to develop the richly colored heart which gives this 

 wood its chief A'alue. 



YELLOW BIRCH. 



[Betula luted.) 



PHYSICAL PROPERTIES. 



Weight of dry n;oo<I. — 4»).,x4 pounds pit cubic foot (;Sargerit). 

 Specific gravity. — 0.6553 i Sargent). 



■At the battle of Carricks Ford, W. Va., in 1861, a portion of the Confederate army, 

 under Gen. Robert S. Garnett, was cut off and driven into uninhabited mountains. Sweet- 

 birch bark is said to have saved the lives of hundreds of soldiers. They subsisted upon it 

 several days while making their way over the mountains to Monterey. Years afterwards 

 their line of retreat could, be traced by observing the peeled trunks of birch trees. 



