380 FOREST PRODUCTS 



proportionate to the leaf area of the trees and it is said that this leaf area 

 is of greater importance than the amount of light the leaves receive. 

 Each tree, therefore, should have full room for development consistent 

 with the largest available number of trees per acre. At the sample time 

 the crown canopy of the trees should be sufficiently dense to prevent the 

 growth of grass underneath and to maintain a good covering of humus 

 and leaves on the ground. 



The gradual northern spring with cold nights, warmer days and slow 

 yield of frost from the ground are conducive to a long and continuous 

 flow of sap. Sudden thaws and rapid changes of temperature are 

 injurious to this flow. The ground should be kept as moist as possible 

 under the humus covering. A good blanket of snow gradually melting 

 off helps very materially to keep the soil moist and, therefore, to induce 

 the maximum flow of sap. 



The careful nurturing of the young maples, the thinning and improve- 

 ment of the grove, etc., are silvicultural problems which are deserving 

 and receiving more and more attention from the sugar makers. Some 

 growers even advise the sowing of 500 Ib. of nitrate of soda per acre to 

 induce vigorous leaf growth and, therefore, sweeter and more sap during 

 the following spring. 



ANNUAL PRODUCTION 



It is estimated that an equivalent of about 45,000,000 Ib. of maple 

 sugar are annually made in this country. This is based upon the assump- 

 tion that all sap is made into sugar. 



The annual production of maple sugar and syrup reached the height 

 of its importance in 1860. At this time the cane sugar came into com- 

 petition with it as a food commodity. In 1870, as a result of this com- 

 petition, the production fell heavily but rose again in 1880 and remained 

 about the same in 1890. About this time both syrup and sugar came 

 into strong demand as table luxuries and this demand stimulated its 

 production very materially. 



In 1900 there were produced about 12,000,000 Ib. of sugar valued at 

 $1,074,260 and 2,056,611 gal. of syrup valued at $1,562,451. In 1909 

 the value of the sugar and syrup crop was $2,541,098. There has been 

 a distinct tendency in the production to fall off in those parts of the 

 country where sugar was produced for home consumption only, whereas 

 in regions where the industry is of larger commercial importance, it has 

 increased in considerable amounts. For example, in Vermont, New 

 York and northern Ohio, the industry has made rapid strides within the 



