Natural Resources
Conservation Service
Ecological site F143XY301ME
Loamy Till Swamp (Northern White Cedar)
Accessed: 04/30/2024
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, known as the Northeastern Mountains, covers approximately 23 million acres of mountains, hills, and valleys in northern Maine, New Hampshire, Vermont, New York, and Massachusetts. The area is sparsely populated, with less than five percent of the land area developed for agriculture, residential, and urban development. About 90 percent of the area is forested, most of which is actively managed for timber. Elevations are mostly between 1,000 to 4,000 feet, with a few isolated peaks more than 5,000 feet above sea level. The present day mountains are but remnants of a much larger ancient range that has been eroding for approximately 500 million years. Bedrock consists of mostly very old metamorphic rock (gneiss, schist, slate, marble, quartzite, etc.) with younger intrusions of igneous rock (e.g. granite and granodiorite) from the Triassic and Cretaceous periods. MLRA 143 differs somewhat geologically from its neighboring MLRAs (142, 144A, 144B, 145, and 146), which have greater amounts of nutrient-rich sedimentary rock. Compared to MLRA 143, they are all lower in elevation, with longer growing seasons large areas that were once submerged by the ocean following glaciation.
The characteristic landforms and soils of northern New England were derived from the massive continental ice sheet that engulfed the region during North America’s most recent glaciation. Mighty glaciers, embedded with sediment and rock fragments, scoured bedrock and compacted mineral beds in a steady march south and east toward the Atlantic Ocean. The softer sedimentary rocks were pulverized into fine silts and clays under the immense weight of ice a mile thick, while the more resistant igneous and metamorphic rocks were sculpted into steep mountains and hills or plucked and dragged along the base of the glacier. With a warming climate, the ice retreated northward, depositing a thin layer of unsorted glacial till sediment atop the newly-exposed bedrock and compacted mineral beds. Deeper mounds of unsorted till formed small hills, kames, moraines and drumlins. Enormous chunks of ice detached as the glacier retreated, melting slowly in place and forming many kettle lakes and basins where water and fine sediments collect. Raging torrents of glacial meltwater dissected much of the barren landscape, entraining coarse and fine sediments, carving river valleys, and leaving well-sorted deposits of mostly sand and gravel along the watercourse. By 10,000 years ago the ice sheet had fully receded from MLRA 143. Silty floodplains developed along perennial rivers, many of which occupy the same channels that once gushed with sediment-rich glacial meltwater. Over time, wet basins accumulated fine sediment, some dried out, and still others became acidified by organic matter inputs from colonizing vegetation.
In terms of climate, MLRA 143 is distinguished from neighboring MLRAs by a shorter growing season and the occurrence of cryic soil temperature regimes at high elevations. The majority of MLRA 143 averages 32 to 44 inches of precipitation annually with a five to six month growing season and frigid winter temperatures. However, the higher elevations may receive up to double the annual precipitation of the lower elevations, and have a three to four month growing season with extremely cold winters. 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.
Classification relationships
This site occurs in Ecological Site Group 3 (Wooded Wetlands) 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 in relatively flat areas (0-8% slopes) near the bottom of watersheds where water saturates lodgment till soils for most of the growing season. Soils are poorly- to very poorly-drained with loamy textures, a mucky peat surface, and a compacted (densic) horizon within ~35 inches of the soil surface. The water table is seasonally high (within 12 inches of the surface) and typically lowers somewhat in late summer and fall. This site often has pit and mound topography, with ponding and organic matter accumulation in the pits, and drier soil conditions on the mounds where most trees are rooted.
Northern white cedar is abundant, often with small amounts of balsam fir, black ash, red maple, white pine, black spruce, and/or yellow birch. Diverse herbs and bryophytes dominate the understory.
Associated sites
F143XY302ME |
Mucky Swamp The Mucky Peat Swamp often occurs downslope of the Loamy Till Swamp as all soils become very poorly drained and soil surface organic layer increases to greater than 16 inches. |
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F143XY502ME |
Loamy Till Toeslope The Loamy Till Toeslope site often occurs upslope of the Loamy Till Swamp, where soils are somewhat poorly- and poorly-drained, rather than poorly- and very poorly-drained. The Loamy Till Toeslope supports hardwood-dominant forests rather than cedar-dominanted forests. |
F143XY503ME |
Loamy Flat The Loamy Flat site has poorly-drained soils throughout, while the Loamy Till Swamp typically has both poorly- and very-poorly drained soils. Loamy Flats support red (and black) spruce, while Loamy Till Swamp is typically too wet for red spruce (though it often has black spruce present). |
Similar sites
F143XY303ME |
Acidic Swamp The Acidic Swamp site has a similar complex of poorly- and very poorly-drained soils, but tends to be wetter, more acidic, and usually has coarser soil textures and weak or non-existent dense compacted layer compared to the Loamy Till Swamp site. The Acidic Swamp is dominated by black spruce rather than northern white cedar. |
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F143XY302ME |
Mucky Swamp Both the Mucky Peat Swamp and the Loamy Till Swamp are dominated by northern white cedar, but the Mucky Peat Swamp is wetter, has a thicker organic soil surface layer, and typically has a more open canopy, allowing more light to reach the forest floor. As a result, the understory is often more productive in the Mucky Peat Swamp. |
Table 1. Dominant plant species
Tree |
(1) Thuja occidentalis |
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Shrub |
Not specified |
Herbaceous |
Not specified |
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