Adirondack-New England highlands, 43,600 mi2 (112,900 km2)
Land-surface form.--This province is composed of subdued glaciated mountains and maturely dissected plateaus of mountainous topography. The mountains and plateaus are underlain by granite and metamorphic rocks and thinly mantled by glacial till. Many glacially broadened valleys have glacial outwash deposits and contain numerous swamps and lakes. The relief is between 1,000 and 3,000 ft (300 and 900 m). Elevations range from 500 to 4,000 ft (150 to 1,220 m); a few isolated peaks are higher than 5,000 ft (1,500 m).
View north from Mt. Washington, the highest point in the Eastern United States, White Mountain National Forest, New Hampshire.
Climate.--The climate, a continental forest type, is characterized by warm summers. Because maritime air masses have year-round access to the eastern seaboard, precipitation is evenly distributed throughout the year, distinguishing this climate from that of the Laurentian Mixed Forest Province. To the west and north, well-defined summer maximum and winter minimum temperatures reflect the predominance of tropical air masses in summer and continental-polar air masses in winter. Winter can be severely cold, as in Wisconsin, but is less so closer to the ocean. Average annual temperatures range from 37 to 52F (3 to 11C). The average length of the frost-free period is about 100 days. Precipitation in Albany, New York, averages 35 in (890 mm) per year. Average annual snowfall is more than 100 in (2,550 mm).
Vegetation.--This mountainous region is in the transition zone between the boreal spruce-fir forest to the north and the deciduous forest to the south. Growth form and species are very similar to those found to the north, but red spruce tends to replace white spruce. Vertical vegetational zonation is present. Valleys contain a hardwood forest where the principal trees are sugar maple, yellow birch, and beech, with an admixture of hemlock. Low mountain slopes support a mixed forest of spruce, fir, maple, beech, and birch. The compensating effect of latitude is apparent in the altitudinal limits of zonation, which rise in elevation as one moves south: the approximate lower limit of spruce and fir on Mt. Katahdin is 500 ft (150 m); in the White Mountains, about 2,500 ft (800 m); in the Adirondack Mountains, 3,000 ft (900 m); and in the Catskills, 3,500 ft (1,100 m). Above the mixed-forest zone lie pure stands of balsam fir and red spruce, which devolve into krummholz at higher elevations. Above timberline on Mount Washington, there is tundralike growth called alpine meadow.
Soils.--Most soils are Spodosols that are stony, cool, and moist.
Fauna.--This community shares some species with both the Laurentian Mixed Forest and boreal forest, but some species are unique to its alpine tundra, such as longtail shrew, boreal (southern) redback vole, gray-cheeked thrush, spruce grouse, and gray jay.