By-products of the Northern Woodlot 235 



Sixty-three per cent of the sap drops before noon. There is 

 a slight betterment in its sugar content as the day advances. 

 The average sugar content of maple sap is about 3 per cent. 

 There is a decrease in solids as well as in sugar as the season 

 advances. 



If three pounds of sugar be made to the tree, from 4 per 

 cent to 9 per cent, according to the size of the tree, is removed. 



The flow of sap is diminished and the flavor of sirup and sugar 

 altered where there has been a severe attack of leaf-eating in- 

 sects the year before. 



There is a difference in opinion as to the quality of the sap 

 yielded by the soft maples (red maple and silver maple), some 

 holding that the sirup is inferior in quality and color, while 

 others say it compares favorably with that of hard maples. How- 

 ever, it is thought that the soft maples do not stand tapping as 

 well as the hard maples and "play out" earlier in the season. 



WINTERGREEN OIL FROM BLACK BIRCH 



The bark of the black or cherry birch (Betula lento} 

 contains a pleasant flavored aromatic oil which is almost 

 identical with the oil of wintergreen made from the com- 

 mon wintergreen (Gaultheria procumbeus) and is widely 

 used as a substitute. This oil is made by distilling the 

 bark and twigs of the birch by the usual distillation pro- 

 cess. Considerable revenue may be secured from the bark 

 and branches of this birch, or the brush after cutting for 

 other purposes. This industry is confined chiefly to the 

 northeastern United States and uses what otherwise would 

 be waste brush fit only to pile and burn. 



TANNING MATERIALS 



The leaves and bark of sumac, the bark of white oak 

 (Quercus alba), chestnut oak (Quercus prinus) and hem- 



