General information

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

MLRA notes

Major Land Resource Area (MLRA): 143X–Northeastern Mountains

MLRA 143 (fig. 143-1) is in Maine (51 percent), New York (27 percent), Vermont (13 percent), New Hampshire (7 percent), and Massachusetts (2 percent). It makes up about 34,409 square miles (89,118 square kilometers). The MLRA consists of rolling hills and mountains covered by Wisconsin till. It is in three parts separated by other MLRAs. The western part is in New York (primarily the Adirondack Mountains). The central part is mainly in the Green Mountains in Vermont and the Berkshires in Massachusetts. The eastern part is in New Hampshire and most of northern Maine. The MLRA is used mainly for forestry and recreational purposes. The western part of MLRA 143 in the Adirondack Mountains has a distinct boundary with the physiographically dissimilar Saint Lawrence-Champlain Plain. The middle part that encompasses the Green Mountains has a diffuse boundary as it blends into the northern part of the New England and Eastern New York Uplands on the foothills of the Green Mountains. The southern boundary of the easternmost part of MLRA 143 has the same diffuse boundary. The northern boundary of the MLRA is the Canadian border.

The westernmost part of this MLRA is primarily in the Adirondack province of the Appalachian Highlands. A small area in the southern end of the western part is in the Mohawk section of the Appalachian Plateaus province of the same division. The easternmost part, primarily in northern Maine, is in the New England Upland section of the New England province of the Appalachian Highlands. The southwestern half of this part is in the White Mountain section of the same province and division, and the middle part of the MLRA is in the Green Mountain section. The mountains and foothills in this MLRA are commonly rounded. They are underlain by bedrock and typically covered with thin deposits of till. The more rugged mountain areas are separated by high-gradient streams coursing through steep areas of colluvium or talus-laden valleys. Many glacially broadened valleys are filled with glacial outwash and have numerous swamps and lakes. The mountains and foothills are moderately steep to very steep, and the valleys are nearly level to sloping.

As the northernmost MLRA in the region with the coldest temperatures and shortest growing season, the Northeastern Mountains have less overall tree diversity, fewer pine and oak trees, and more abundant spruce and fir trees than neighboring MLRAs. The variability in microtopography on this site results in a patchy mosaic of plant communities. Silver maple is the most common overstory species, with diverse grasses and herbs indicating differences in soil wetness throughout the site due to slight variability in elevation above the water table. This site is subject to ice scour and flooding, but the most extensive disturbance is cultivation. These broad, flat landforms are nutrient rich with high water-holding capacity. These factors along with their adjacency to rivers made them ideal farming locations for early settlers, much of which continues today. The effects of altered flow regimes from modern dams may also be significant but require further study.

Classification relationships

This site occurs in Ecological Site Group 1 (Floodplains) of MLRA 143 (The Northeastern Mountains), in the Northeastern Forage and Forest Region (Land Resource Region R).

The Northeastern Forage and Forest LRR includes all of Maine, New Hampshire, Vermont, Rhode Island, and Connecticut, as well as large portions of Massachusetts, New York, New Jersey, Pennsylvania, and Ohio. Its southern boundary marks the extent of the Wisconsin ice sheet, which engulfed the entire LRR as recently as 10,000 to 15,000 years ago. Erosional and depositional processes associated with glaciation created many of the topographic patterns that distinguish MLRAs within the Northeastern region. Harder granitic and metamorphic bedrock to the north were more resistant to glacial erosion, resulting in the relatively nutrient poor mountains of MLRA 143; whereas nutrient-rich sedimentary bedrock of MLRAs 139, 140, and 146 resulted in relatively flat, fertile landscapes ideal for cultivation. Other areas were depressed below sea-level by the sheer mass of the glacier, resulting in pockets of marine sediments which distinguish MLRAs 142, 144A, 144B, and 145.

Precipitation is sufficient to support productive forestland throughout the Northeastern region. Still, a latitudinal temperature gradient from mesic to frigid soil temperatures results in a general transition from central hardwoods and pine in the southern MLRAs to northern hardwoods and spruce-fir forests farther north (no true boreal forests exist in the region). Elevations are generally low throughout the Northeastern region, with the exception of MLRA 143 which has many high mountain ecosystems with cryic temperature regimes and alpine vegetation above the tree line.

Ecological site concept

This site occurs next to small rivers and streams and includes a
complex of soils and landforms associated with floodplains. Poorly drained
banks occur nearest the channel, with broad, somewhat
poorly to moderately well-drained floodplains behind. Side
channels often carry large amounts of water into the floodplains at
high flows, and the lowest areas of the floodplain, including poorly and
very poorly-drained oxbows and depressions, may be ponded
at times. Soils are derived from alluvium, are typically silt loams to
fine sands in texture, and may have gravel or sand layers from
particular flooding events. Poorly-drained soils are often organic
over alluvium.

The variability in microtopography on this site results in a patchy
mosaic of plant communities, but trees are typically lacking.
Diverse grasses and herbs indicate differences in soil wetness
throughout the site due to slight variability in elevation above the
water table. This site is subject to flooding, but the most extensive
disturbance is ice scour, which periodically removes woody
species, maintaining the herbaceous dominance in the plant
community. Beaver activity can alter reaches of this site by slowing
the flow, which results in less scour and subsequently greater
shrub dominance. These narrow landforms are nutrient rich with
high water-holding capacity, but are too small for extensive
cultivation. Much of this site occurs upstream of dams, though
altered flow regimes may have significant impact on this site.
Further study is needed to better describe the properties and
disturbances that define this site concept.

Similar sites

Table 1. Dominant plant species