Natural Resources
Conservation Service
Ecological site F143XY502ME
Loamy Till Toeslope
Last updated: 10/07/2024
Accessed: 11/13/2024
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 5 (Loamy Forests) 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 on gentle foot and toe slopes (0-15%) at the base of watersheds where water and nutrients accumulate near slope breaks. Soils are underlain by a densely compacted till layer within 43 inches of the soil surface, which perches water and nutrients in the plant rooting zone. Occasionally groundwater seeps out at the surface, leaving rivulets as useful site indicators. The resulting plant community is highly-productive and most commonly dominated by northern hardwoods, though red spruce and balsam fir are often abundant, particularly in flatter areas. Abundant yellow birch is a good indicator of this site.
Associated sites
F143XY503ME |
Loamy Flat The Loamy Flat site occurs downslope in the watershed from the Loamy Till Toeslope on flatter landscape positions where water is more stagnant. |
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F143XY301ME |
Loamy Till Swamp (Northern White Cedar) The Loamy Till Swamp site occurs lower in the watershed than the Loamy Till Toeslope site. The two sites occur together along a soil drainage gradient from somewhat poorly- to poorly- and very poorly-drained. |
F143XY504ME |
Enriched Loamy Cove The Enriched Loamy Cove site is richer than the Loamy Till Toeslope, and occurs in areas where the most amount of nutrients accumulate, such as small drainageways. |
F143XY501ME |
Loamy Slope The Loamy Slopes site often occurs upslope of the Loamy Till Toeslope, which receives extra water and nutrients from above, enriching the toeslope soils somewhat. |
Similar sites
F143XY503ME |
Loamy Flat The Loamy Flat site and Loamy Till Toeslopes site share many of the same soils, but Loamy Flats occur on flatter areas grading into wetlands and produce spruce-fir forests, whereas the Loamy Till Toeslope occurs at the base of slopes and produces semi-rich mixedwood forests. |
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F143XY504ME |
Enriched Loamy Cove The Enriched Loamy Cove site occurs along drainageways, produces hardwood forests (typically with white ash, yellow birch, sugar maple, and/or beech), has a thick dark soil surface horizon, and has rich site indicators. By contrast, the Loamy Till Toeslope occurs at the base of slopes and produces semirich hardwood or mixedwood stands. |
F143XY501ME |
Loamy Slope The Loamy Slopes site is predominantly well and moderately well-drained soils (sometimes with somewhat poorly-drained inclusions) that produce mostly northern hardwoods, whereas the Loamy Till Toeslopes site consists of somewhat poorly- to poorly drained soils and can produce more mixedwood stands. |
F143XY702ME |
Shallow And Moderately Deep Till The Shallow and Mod-deep Till site produces mixedwood communities similar to Loamy Till Toeslope, but typically occurs on hill shoulder positions and other well- to excessively-drained areas rather than somewhat poorly and poorly-drained toeslopes positions. Shallow and Mod-deep Till refers to bedrock within 40 inches of the soil surface, whereas Loamy Till Toeslope lacks bedrock and has a dense soil horizon within 43 inches of the soil surface. |
Table 1. Dominant plant species
Tree |
Not specified |
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Shrub |
Not specified |
Herbaceous |
Not specified |
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