11 



Seedlings, although not killed by complete shade, are kept sup- 

 pressed and grow slowly; but if they have germinated in the open, 

 or the forest above them is removed, they grow up into thickets of 

 remarkable density. In such a condition the struggle between the 

 young trees is so fierce that the development of even the most 

 thrifty is seriously retarded. The species being so tolerant of shade 

 and by nature so vigorous, no individual gives up the struggle, 

 but does its utmost to overtop the others and gain the sunlight. 

 As a result the stand keeps its extreme density for a long period, 

 and each tree grows long and spindling. The forest-grown tree devel- 

 ops slowly on this account, and has a long, clean stem and a small 

 crown, while the roadside maple has a short trunk and a great egg- 

 shaped crown of dense foliage. The root system tends to be shallow, 

 with many laterals and an undeveloped taproot. In the forest this 

 character is more marked than in field or roadside specimens, and 

 any sudden opening up of the stand may result in loss by windfall 

 or by a drying out of the roots. 



There is no doubt that the quantity of sap that a tree yields stands 

 in direct relation to the size of its crown, but many sugar makers 

 believe that trees in a forest produce more sap than those in a grove. 

 The explanation is found in the fact that the forest floor with its cov- 

 ering of litter and humus contributes to the vitality of the trees more 

 than the grass carpet of a grove. To obtain a heavy sap production, 

 a complete crown cover and a rich deposit of humus are of vital impor- 

 tance. (See pp. 14, 15, 26.) 



Within its wide range the sugar maple appears as a predominant 

 tree only in the New England States, New York, southern Canada, 

 northern and western Pennsylvania, and in parts of Ohio, Indiana, 

 Illinois, Michigan, Wisconsin, and Minnesota. In the southern Appa- 

 lachians it occurs in scattered bodies where climatic conditions are 

 similar to those of the North, confining itself chiefly to north slopes or 

 to the coves, on moist, well-drained, rich soils where the heat of the 

 sun is tempered. As a rule, it associates with the beech, birches, and 

 basswood, but also mixes with the yellow poplar, hickories, and other 

 hardwoods, and with hemlock and some of the eastern spruces. At 

 the heads of the coves and in the bottoms it often forms pure stands fit 

 for commercial tapping, and its reproduction is everywhere excellent. 



In its northern home it is a principal forest tree and often forms 

 from 25 to 75 per cent of the total stand. It prefers a moist but 

 well-drained soil, and seems to do its best on glacial drift or on rocky 

 hillsides and benches. In the cool atmosphere of this region all 

 aspects are equally acceptable, but it avoids or grows sparsely on 

 ridge crests, generally leaving the ground in such situations to spruce 

 or to beech. In the extreme northern part of New York State and 



252 



