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): Mesic Soil Temperature Regime
The lower St. Lawrence and Champlain Valleys are characterized with soils in the mesic soil temperature regime (mean annual soil temperature between 46°F and 59°F) at 20 inches below the surface or at a densic, lithic, or paralithic contact, whichever is shallower.
The Mesic Soil Temperature Regime (STR) will have a longer growing season than the upper St. Lawrence and Champlain Valleys which are characterized with soils in the frigid STR. Species more tolerant of milder year round temperatures would also be evident in the mesic LRU.
Land Resource Region: R - Northeastern Forage and Forest Region
MLRA: 142X–St. Lawrence-Champlain Plain
LRU: B - Mesic Mean Annual Soil Temperature
Ecological site concept
The site occurs on hills, knolls, ridges, benches, and till plains. Slopes are mostly less than 25 percent but can range up to 60 percent.
The site consists of moderately deep to very deep, well drained soils that formed in glacial till derived mostly from limestone. Representative soils are Dover, Galway, Lowville, Nellis, Palatine, Pittsfield, and Stockbridge.
The reference community coincides with with Vermont's Mesic Maple-Ash-Hickory-Oak Forest and Transition Hardwoods Limestone Forest (Thompson and Sorenson, 2000).
Shallow Rich Till Upland
Rich Till Upland Frigid
Table 1. Dominant plant species
(1) Acer saccharum
(1) Alnus incana ssp. rugosa
(1) Symplocarpus foetidus
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