especially when young. The seedlings are very thrifty and persist 

 under shade. On open areas young maples sometimes form very 

 dense thickets. This density of stand is maintained for a long period, 

 so that the forest-grown tree develops slowly and has a long, clean 

 steam and a small crown. Toward the southern limit of its range 

 the sugar maple requires considerable shade and does best on cool, 

 moist sites, such as north slopes. 



The sugar maple is a somewhat slow -growing, long-lived tree. 

 It develops much more slowly than the other maples up to the fifth 

 year. Plantations of this species, however, make an average height 

 growth of about 1 foot per year during the first thirty or forty 

 years, the rate decreasing in later life. With favorable site condi- 

 tions and proper density of stand the trees should be 35 to 40 feet in 

 height with a diameter of 6 to 8 inches at thirty years after planting. 



Sugar maple is attacked by a number of injurious insects. Trees 

 are often seriously injured and sometimes killed by the large maple 

 borer, and the foliage is in some seasons severely eaten by the forest 

 tent caterpillar, fall webworm, and other caterpillars. Aphides fre- 

 quently infest the tree, and the cottony maple scale is often very 

 troublesome and destructive. The tree is the host of many fungi 

 which produce diseases of varying degrees of injury. 



The sugar maple is sensitive to severe frost and drought, but wind, 

 snow, and ice seldom do it great damage. Brush fires are likely to 

 kill the trees. In towns it is liable to injury from gas, dust, and 

 smoke, so that it often is a failure as a street tree. 



Too deep and frequent tapping of the maple for sugar production 

 weakens it so that fungi, and possibly insects, gain entrance and the 

 tree dies. If properly practiced, however, tapping does little injury. 



ECONOMIC USES. 



The wood of the sugar maple is heavy, strong, dense, and very hard, 

 but not durable in contact with the soil. It is susceptible of fine polish 

 and is used in large quantities for interior finish, floors, musical in- 

 struments, furniture, wooden ware, vehicles, cooperage, and novelties. 

 The wood stands alternate wetting and drying well, and is therefore 

 one of the best for the manufacture of washing machines. " Curly " 

 and " bird's-eye " maple, obtained from this species, are desirable for 

 finishing and cabinet work. The wood makes charcoal of unsur- 

 passed quality, is a source of wood alcohol, and has a very high fuel 

 value. 



The chief value of the sugar maple for economic planting is as a 

 sugar producer. The sap contains from 2 to 6 per cent of sugar. 

 Three to 9 per cent of the total sap content of the tree may be utilized 

 for sugar making without dangerously lessening the tree's vitality. 



[Cir. 95] 



