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.
Major Land Resource Area (MLRA): 142X–St. Lawrence-Champlain Plain
This MLRA is a glaciated area of low relief dominated by broad expanses of nearly level, sandy deltas and shallow lacustrine basins or plains punctuated by low hills of glacial till. Rivers and streams have cut relatively deep but narrow valleys across the plain. Elevation ranges from 80 to 1,000 feet, increasing gradually from the St. Lawrence River southward and from Lake Champlain to the east and west. Local relief generally is less than 30 feet, but glacial till ridges, till plains, and some outwash terraces rise 15 to 80 feet above the adjacent plains.
This area has been glaciated, and a thin mantle of till covers most of the bedrock. Extensive areas of sandy glacial outwash and eolian deposits also occur. Some glacial lake sediments have been deposited above glacial moraines. These deposits are thickest in the valleys and thinnest on the ridges and highlands. During the later stages of the Wisconsin glacial period, seawater entered the Champlain Valley and deposited marine sediments that were later covered by freshwater sediments. The marine deposits are unique to the area.
This area supports hardwoods. The beech-birch-sugar maple forest type is the dominant climax forest type on uplands. Associated with this type are basswood, American elm, maple species, white ash, black cherry, and white pine. The aspen-birch type, earlier in succession, is economically important. Such species as eastern hemlock, red maple, American elm, and spruce are on wet soils.
Some of the major wildlife species in this area are white-tailed deer, red fox, raccoon, beaver, woodchuck, muskrat, cottontail, ruffed grouse, and woodcock.
Land Resource Unit (LRU): Frigid Soil Temperature Regime
The upper St. Lawrence and Champlain Valleys are characterized with soils in the frigid soil temperature regime (mean annual soil temperature greater than 32°F but less than 46°F and with a difference between mean summer and mean winter soil temperatures greater than 41°F at 20 inches below the surface or at a densic, lithic, or paralithic contact, whichever is shallower).
The Frigid Soil Temperature Regime (STR) will have shorter growing season than the lower St. Lawrence and Champlain Valleys which are characterized with soils in the mesic STR. Species more tolerant of colder year round temperatures would also be evident in the Frigid LRU.
Land Resource Region: R - Northeastern Forage and Forest Region
MLRA: 142 - St. Lawrence-Champlain Plain
LRU: A/02 - Frigid Mean Annual Soil Temperature
Domain: 200 - Humid Temperate
Division: 210 - Warm Continental
Province: 211 - Northeastern Mixed Forest
Section: 211E - St. Lawrence and Champlain Valley
Subsections: 211Ea - St. Lawrence Glacial Marine Plain
Level I: 8 - Eastern Temperate Forests
Level II: 8.1 - Mixed Wood Plains
Level III: 83 - Eastern Great Lakes Lowlands
Level IV: 83d - St. Lawrence Lowlands
83e - Upper St. Lawrence Valley
Ecological site concept
Mean annual precipitation is 38 inches and evenly distributed throughout the year. Most of the rainfall occurs as high intensity, convective thunderstorms during the summer. Snowfall is heavy from late in autumn to early spring. The average temperature in winter is 18°F and in summer it is 66°F. Average frost-free and freeze-free days are 124 and 147, respectively.
The soils formed in predominantly well decomposed organic material underlain by clayey deposits.
The site occurs in depressions on till plains and lake or marine plains. Slope ranges from 0 to 2 percent
The site consists of very deep, very poorly drained, organic soils in depressions on till plains and lake or marine plains. Soils formed in predominantly well decomposed organic material underlain by clayey deposits. Soil are often, but not always, nutrient (calcium) rich.
Plant communities associated with nutrient rich peatlands characterize the site. Minerotrophic peatlands are variable based on local hydrology, minerology, and geomorphic conditions. Plant communities are typically conifer or mixed hardwood-conifer forests, woodlands, or shrublands. The site includes northern white cedar swamp, red maple-tamarack swamp, and rich shrub fen (Edinger et al 2014, Thompson and Sorenson 2005).
Common trees include northern white cedar, red maple, tamarack, eastern hemlock, black spruce, and yellow birch. Common shrubs include red osier dogwood, speckled alder, highbush blueberry, winterberry, swamp birch, alder-leaf buckthorn and poison sumac. Herbaceous plants include skunk cabbage, cinnamon fern, marsh fern, starflower and numerous sedges. Strongly minerotrophic peatlands may be dominated by either low or tall shrubs with a limited herb and tree layer.
Natural disturbances influencing the reference plant communities include ponding and duration, drought, insect damage, beaver activity, and tree falls.
Wet Lacustrine Depression
Poorly to very poorly drained depressions. Organic layer less than 16 inches thick.
Table 1. Dominant plant species