8 THE PRODUCTION OF MAPLE SIRUP AND SUGAR. 



Maple trees are often seriously injured by an insect commonly 

 called the " maple worm," concerning which information may be had 

 from Circular 110 of the Bureau of Entomology, United States De- 

 partment of Agriculture. 



In the present discussion the sugar maple is not considered as a 

 lumber tree, for which a long stem free of branches is desired, but 

 rather as a paying producer of sap. Under this aspect a silvicultural 

 problem is presented radically different from that which ordinarily 

 confronts the forester. (See p. 9.) The full and heavy crown with 

 a large leaf surface must be developed in place of the long, clear 

 stem. The sap flow must be continuous and plentiful. The best sap 

 flow is where the transition from winter to spring is slow, where the 

 days are warm and sunny and the nights frosty. These conditions 

 do not occur throughout the entire range of the species. A locality 

 wherein the ground thaws quickly and which has no great variation 

 of temperature between day and night is not suitable for sap produc- 

 tion. The "season" must be long enough, also, to insure sap in 

 merchantable quantities. Such conditions are characteristic only in 

 the Northern States, and as sugar making extends farther south it 

 can be profitable only at altitudes which reproduce the climatic con- 

 ditions of the North. 



THE BLACK MAPLE. 



The black maple is generally considered superior to all others as a 

 producer of sap. How far this is true is uncertain. In its general 

 silvical characteristics it is similar to the sugar maple, save in the 

 fact that it seems to prefer lower land, such as the banks of streams 

 and rich alluvial river bottoms. It is found in Vermont on the shores 

 of Lake Champlain, and ranges southward, west of the Alleghenies, 

 from Minnesota to Arkansas and eastern Kansas. 



THE RED MAPLE. 



The red maple has the widest range of all its family in America. 

 The natural home of this tree is along the borders of streams and 

 on low, swampy ground. In the North it often forms a pure growth 

 in such places, but it is along the Ohio and the Mississippi and their 

 tributaries that it reaches- its greatest perfection. Like the sugar 

 maple it is tolerant of shade, and seedlings sprout plentifully from 

 the heavy crops of seeds, which ripen in the late spring or early 

 summer. As a swamp tree it associates in the Southern and Middle 

 States with the sweet magnolia and loblolly bay, the bald cypress, 

 various oaks, and the red, black, and cotton gums. It does well, 

 also, on less moist lands. It is generally of vigorous growth, but 

 the grown trees are inclined to unsoundness at the butt. As a sugar- 

 producing tree it enters into consideration in the Middle and West- 

 ern States only where the sugar maple is not plentiful. It has an 

 abundant flow of sap which is much lower in sugar content than the 

 sugar maple. On account of its early flow of sap it is often tapped 

 at the first of the season to produce the earliest maple products. 



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