K.MlMkKAI. I'ORKSTKV IN Till". ADI UONDACKS 117 



to the edpe of the swamp, stream, or lake and is marked by the ap])ear- 

 ance of soft majiie and birch on a moist soil covered with humus and 

 lacking the spongy characteristic of the swamp. 



The upper margin is marked by the disappearance of balsam and 

 appearance of beech in the mixture. The soil loses its humus cover- 

 ing, and there a])pears instead a shallow layer of hardwood leaf mould 

 with a firm, well-drained soil beneath. Sugar maple is not commonly 

 found in this tyijc. The characteristic species are red spruce, balsam, 

 hemlock, yellow birch, and red maple. Birch exceeds in number all 

 other hardwood species in the type. The predominance of softwood 

 species, and moist condition of soil when shaded, and extreme dryness 

 when not shaded, influence to a marked degree the amount and char- 

 acter of reproduction to be expected. 



Mixed Hardivood. — This type has already been defined as to its 

 lower margin, and needs only general characterization. While that 

 zone of the ridge slopes having comparatively deep soil may be defined 

 as hardwood type up to the point in elevation where spruce again 

 appears as the dominant, there is still a wide variation in hardwood 

 areas. The amount of moisture and soil depth both influence the 

 composition. The lower, moist hardwood land will have more birch 

 than the better drained parts. Areas of several acres may be found 

 covered by stands of pure sugar maple, while shallow soils on exposed 

 ledges are pure softwood, largely hemlock. 



The hardw^ood type has reproduced itself by natural selection mainly, 

 yet the characteristic of windfall and even aged growth is common on 

 small areas. Variation in the type is wide, and the composition of the 

 forest changes in the several sections of the Adirondack region. 



Upper Slope. — This has been defined as to its lower margin as that 

 point in elevation in the mixed hardwood forest where spruce again 

 becomes a dominant. As a softwood forest the type extends over the 

 upper slopes and mountain summits, grading off, in its upper limits, 

 according to elevation and locality, into the typical stunted growth of 

 a sub-arctic or alpine type of vegetation. Yellow birch is the most 

 widely distributed and best developed hardwood tree of this type. It 

 can thrive better than maple or beech on the thin soils, and can repro- 

 duce best of all hardwoods in the deep humus found under the type. 



INFLUENCE OF LOGGING ON THE FOREST 



The early logging operations may be designated as a selection method, 

 in which the amount of timber removed was not enough to interfere 



