PLANT INDUSTRIES 311 



maple sap and, as ordinarily used, it contains from 30 to 40 

 per cent of the water originally in the sap. 1 



The sugar-making season is short, because, as soon as new 

 protoplasm is developed in great abundance, the sap no longer 

 makes acceptable sugar. Maple trees may be used from year to 

 year indefinitely without apparent injury due to the withdrawal 

 of sap, but the stem may be weakened by too frequent boring 

 at one level, and the wound, though it heals in one or two 

 years, may serve as a place of entrance for disease organisms. 



\ Cuban sugar-cane field 



Standing cane is seen at the left, between the men and the trees ; in the foreground 



the men are loading sap-laden stalks upon the carts. Note the heavy soil covering 



of leaves that have been stripped from the sugar-cane stalks 



Sugar-maple groves are being planted in some places for 

 the sugar product, but other plants of more rapid growth and 

 larger sugar production will doubtless prevent maple sugar 

 from entering largely into sugar consumption. The distinctive 

 flavor of maple sugar and sirup, however, will enable it to 

 continue as a highly desired article of commerce. 



1 "The Maple Sugar Industry," Bulletin 59, Bureau of Forestry, U.S. 

 Dept. Agr., 1905 ; " Maple Sap Sirup," Bulletin 134, Bureau of Chemistry, 

 U.S. Dept. Agr., 1910 ; " The Production of Maple Sirup and Sugar," Fann- 

 ers' Bulletin 616, U.S. Dept. Agr., 1912. 



