Natural Resources
Conservation Service
Ecological site F146XY061ME
Shallow Loamy Till
Last updated: 5/20/2025
Accessed: 08/17/2026
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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): 146X–Aroostook Area
This area is entirely in Maine and it makes up about 1,275 square miles (3,305 square kilometers). Presque Isle is the largest city in the area. Interstate 95 ends in the town of Houlton, at the border with New Brunswick, Canada. Aroostook State Park, Fort Kent Historic Site, and Loring Commerce Center are in this area. The Big Rock ski area is in the middle of this MLRA and is on the highest point, which is Mars Hill Mountain.
Ecological site concept
This site occurs where soils are shallow over bedrock, often with small areas of bedrock protruding through the soil. It is found on all bedrock types in the region on many landforms including ridges, hilltops, hill shoulders, drumlins and till plains. The site is somewhat excessively drained and relatively dry soil conditions overall. The plant community is a softwood-dominated mixed wood forest with sparse understory species. Red spruce, balsam fir, hemlock and/or white pine dominate the overstory, with red maple and American beech as common hardwood species. Northern white cedar may be present on calcareous bedrock where soil pH is around 6.0 or higher. Club mosses, starflower, wild sarsasparilla, and intermediate woodfern are common understory species. In exposed areas, the shallow rooting zone may result in significant quantities of downed wood and snags on this site.
This site is subject to cultivation, logging, wind, insects and disease, and other natural and human disturbances resulting in a variety of alternative states. Sites that are cleared and cultivated are typically those with soil pH greater than 6.0. Abandoned cropland may remain as open hay land, or transition to pine, spruce-fir, or reference mixedwood forests.
When managed for timber production, several different ecological states are possible. The pine forest state, reference mixed conifer state, and spruce-fir state are managed to maintain dominance of their respective conifer species, and to facilitate profitable harvests along predictable timelines. Hemlock forests may also result from logging practices, though these are typically less-desirable and may result from selective harvest of more valuable species, leaving the hemlock behind. As hemlock increases on the site, it inhibits the establishment of other species by shading, reducing soil moisture availability to other plants, and especially by acidifying the soil. With sufficient economic inputs, any of the states that occur on this site may transition from one to another, however, due to cost limitations, forests are typically managed for whatever timber species are currently present on the site.Associated sites
F146XY081ME Loamy Acidic Till
This site often grades into the Loamy Acidic Till site as soils become deeper. Typically the Shallow Loamy Till site is upslope from the Loamy Acidic Till site.
F146XY082ME Loamy Calcareous Till
This site can grade into the Loamy Calcareous Till site as soils become deeper. Typically the Shallow Loamy Till site occurs upslope from the Loamy Calcareous Till site.
Similar sites
F146XY084ME Silty
These two sites have similar species composition and plant community dynamics, however soil depth and drainage are significantly different. These differences are likely to be reflected in the understory species and site interpretations, such as site index.
Table 1. Dominant plant species
Tree (1) Tsuga canadensis
(2) Pinus strobusShrub (1) Vaccinium angustifolium
(2) Kalmia angustifoliaHerbaceous (1) Maianthemum canadense
(2) Trientalis borealisPhysiographic features
This site occurs where soils are shallow over bedrock, often with small areas of bedrock protruding through the soil. It is commonly found on ridges, hilltops, and hill shoulders, but may also be found on drumlins and till plains. Slopes are usually 8-25 percent, but can range from 0-45 percent. The site is excessively drained with relatively dry soil conditions overall.
Table 2. Representative physiographic features
Landforms (1) Ridge
(2) Hill
(3) Till plain
Runoff class Low to high Flooding frequency None Ponding frequency None Elevation 90 – 2500 ft Slope 0 – 25 % Water table depth 72 – 0 in Aspect Aspect is not a significant factor Climatic features
The climate of this site is characterized by cold, snowy winters, and cool summers. Precipitation is nearly equally distributed throughout the year, with slightly more moisture falling in June-October. During winter months, and sometimes fall and spring, cold winds from the north bring severe weather events. The effects of a relatively short growing season are somewhat mitigated by long summer days associated with the high latitudes of the region. Occasionally high winds, microbursts, or freezing rain events damage vegetation over small portions of the landscape.
Table 3 Representative climatic features
Frost-free period (characteristic range) 80-90 days Freeze-free period (characteristic range) 130-130 days Precipitation total (characteristic range) 40-40 in Frost-free period (actual range) 60-110 days Freeze-free period (actual range) 100-140 days Precipitation total (actual range) 40-40 in Frost-free period (average) 90 days Freeze-free period (average) 130 days Precipitation total (average) 40 in Characteristic rangeActual rangeBarLineFigure 1. Monthly precipitation range
Characteristic rangeActual rangeBarLineFigure 2. Monthly minimum temperature range
Characteristic rangeActual rangeBarLineFigure 3. Monthly maximum temperature range
BarLineFigure 4. Monthly average minimum and maximum temperature
Figure 5. Annual precipitation pattern
Figure 6 Annual average temperature pattern
Climate stations used
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(1) FT KENT [USC00172878], Fort Kent, ME
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(2) CARIBOU MUNI AP [USW00014607], Caribou, ME
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(3) ALLAGASH [USC00170200], Saint Francis, ME
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(4) BRIDGEWATER [USC00170833], Bridgewater, ME
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(5) HOULTON 5N [USC00173944], Houlton, ME
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(6) PRESQUE ISLE [USC00176937], Presque Isle, ME
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(7) HOULTON INTL AP [USW00014609], Houlton, ME
">Influencing water features
Due to its landscape position, this site is not affected by streams or wetlands.
Soil features
The soils of this site are shallow over bedrock, often with small areas of bedrock protruding through the soil. Rock fragments are typically not found on the soil surface, but they are common in the soil and tend to increase in volume with depth. Total soil depth ranges from 10-23 inches resulting in low water holding capacity. This site is somewhat excessively drained with relatively dry soil conditions overall. This site exhibits a broad range in soil pH associated with various bedrock types, however, the shallow, dry growing conditions result in similar site potential for plant community dynamics. The soil moisture regime is udic, and the soil temperature regime is frigid.
Table 4. Representative soil features
Parent material (1) Melt-out till – phyllite
(2) Subglacial till – slate
(3) Supraglacial meltout till – limestone and shale
Surface texture (1) Silt loam
(2) Channery silt loam
(3) Very channery silt loam
Family particle size (1) Loamy
Drainage class Somewhat excessively drained Permeability class Very slow to slow Soil depth 10 – 23 in Surface fragment cover <=3" Not specified Surface fragment cover >3" 0 – 2 % Available water capacity
(0-40in)1.5 – 5.8 in Calcium carbonate equivalent
(0-40in)Not specified Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)3.6 – 7.8 Subsurface fragment volume <=3"
(Depth not specified)0 – 34 % Subsurface fragment volume >3"
(Depth not specified)0 – 18 % Ecological dynamics
[Caveat: The vegetation information contained in this section and is only provisional, based on concepts, and future projects support validation through field work. *] The vegetation groupings described in this section are based on the terrestrial ecological system classification and vegetation associations developed by NatureServe (Comer 2003) and localized associations provided by the Maine Natural Areas Program (Gawler and Cutko, 2010).
The plant community is a softwood-dominated mixed wood forest with sparse understory species. Red spruce, balsam fir, hemlock and/or white pine dominate the overstory, with red maple and American beech as common hardwood species. Northern white cedar may be present on calcareous bedrock where soil pH is around 6.0 or higher. Club mosses, starflower, wild sarsasparilla, and intermediate woodfern are common understory species. In exposed areas, the shallow rooting zone may result in significant quantities of downed wood and snags on this site.
This site is subject to cultivation, logging, wind, insects and disease, and other natural and man-made disturbances, resulting in a variety of alternative states. Sites that are cleared and cultivated are typically those with soil pH greater than 6.0. Abandoned cropland may remain as open hay land, or transition to pine, spruce-fir, or reference mixedwood forests.State and transition model
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Click on state and transition labels to scroll to the respective textState 1 submodel, plant communities
State 2 submodel, plant communities
State 1
Reference State (minimally managed)Community 1.1
White Pine - Mixed Conifer ForestThis ecological site occurs on sandy to loamy mesic soils (usually well drained, occasionally imperfectly drained or very well drained), often with a slowly decomposing duff layer of conifer needles. Soils are generally shallow (
Resilience management. Maine Natural Areas Program State Rank: S5 Secure – At very low risk or extinction or elimination due to a very extensive range, abundant populations or occurrences, and little to no concern from declines or threats. Demand for white pine has considerably reduced mature, undisturbed examples of this type. Most sites known to be of high ecological quality lack formal protection. Maintaining the surrounding lands as forest is important in conserving particular stands of this type, particularly given that many known examples are small (<50 acres). (Gawler and Cutko, 2010)
Dominant plant species
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eastern white pine (Pinus strobus), tree
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eastern hemlock (Tsuga canadensis), tree
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red maple (Acer rubrum), tree
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arborvitae (Thuja occidentalis), tree
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beaked hazelnut (Corylus cornuta), shrub
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lowbush blueberry (Vaccinium angustifolium), shrub
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bristly dewberry (Rubus hispidus), shrub
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wavy hairgrass (Deschampsia flexuosa), grass
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bigleaf aster (Eurybia macrophylla), other herbaceous
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marginal woodfern (Dryopteris marginalis), other herbaceous
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rock polypody (Polypodium virginianum), other herbaceous
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wild sarsaparilla (Aralia nudicaulis), other herbaceous
Dominant resource concerns
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Plant productivity and health
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Plant structure and composition
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Plant pest pressure
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Terrestrial habitat for wildlife and invertebrates
Community 1.2
Hemlock ForestHemlock forests are usually on slopes (typically 5-50%) and ravines, with well drained loamy soil. On lower slopes and flats, soils may grade to imperfectly drained. Soils tend to be shallow (50% cover) or, less often, hemlock is co-dominant with red spruce, red oak, yellow birch, red maple, or sugar maple. The conifer canopy allows little light to reach below, and the shrub, herb, and bryoid layers are sparse (each usually
Resilience management. Maine Natural Areas Program State Rank: S4 Apparently Secure – At fairly low risk of extinction or elimination due to an extensive range and/or many populations or occurrences, but with possible cause for some concern as a result of local recent declines, threats, or other factors. Demand in the 1700s -1800s for hemlock considerably reduced mature, undisturbed examples of this type, yet poor market conditions more recently have caused hemlock to be left in partial harvests; many of these legacy trees are quite old. Some evidence suggests that hemlock is less successful at maintaining itself in the face of human-caused disturbance than are northern hardwoods. Most sites known to be of high ecological quality are in southern and central Maine and lack formal protection. Maintaining the surrounding lands as forest is important in conserving particular stands of this type, particularly given that many known examples are small (<50 acres). (Gawler and Cutko, 2010)
Dominant plant species
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eastern hemlock (Tsuga canadensis), tree
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northern red oak (Quercus rubra), tree
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red spruce (Picea rubens), tree
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sugar maple (Acer saccharum), tree
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eastern white pine (Pinus strobus), tree
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yellow birch (Betula alleghaniensis), tree
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paper birch (Betula papyrifera), tree
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red maple (Acer rubrum), tree
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Canada mayflower (Maianthemum canadense), other herbaceous
Dominant resource concerns
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Plant productivity and health
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Plant structure and composition
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Plant pest pressure
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Terrestrial habitat for wildlife and invertebrates
Community 1.3
Jack Pine WoodlandThese are open canopy woodlands (
Resilience management. Maine Natural Areas Program State Rank: S3 Vulnerable – At moderate risk of extinction or elimination due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors. Most sites contain evidence of past fire, which in most cases is required to open the serotinous cones of jack pine. Natural fires in these woodlands may increase the ability of jack pine to maintain its dominance over potentially invasive or fire sensitive tree species. Several sites are on public lands or private conservation lands. (Gawler and Cutko, 2010)
Dominant plant species
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black spruce (Picea mariana), tree
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jack pine (Pinus banksiana), tree
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red spruce (Picea rubens), tree
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catberry (Ilex mucronata), shrub
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sheep laurel (Kalmia angustifolia), shrub
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black huckleberry (Gaylussacia baccata), shrub
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lowbush blueberry (Vaccinium angustifolium), shrub
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northern mountain cranberry (Vaccinium vitis-idaea ssp. minus), shrub
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bunchberry dogwood (Cornus canadensis), other herbaceous
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starflower (Trientalis borealis), other herbaceous
Dominant resource concerns
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Plant productivity and health
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Plant structure and composition
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Plant pest pressure
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Wildfire hazard from biomass accumulation
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Terrestrial habitat for wildlife and invertebrates
Community 1.4
Birch - Oak Talus WoodlandSites typically occur on dry, acidic talus substrates with various aspects. Documented elevations are from nearly sea level to about 1500’. These community types are partial canopy deciduous woodlands or patches of woodland among talus areas. Overall canopy closure may be
Resilience management. Maine Natural Areas Program State Rank: S3 Vulnerable – At moderate risk of extinction or elimination due to a fairly restricted range, relatively few populations or occurrences, recent and widespread declines, threats, or other factors. Talus woodlands receive little human use because of their inaccessibility and low timber value; however, areas at the base of talus slopes that receive water and nutrients from above sometimes have enough large trees to make logging economical. Conservation of these sites should include the range of talus forest cover, from the base of the slope on up, with a buffer of adjacent forest cover. (Gawler and Cutko, 2010)
Dominant plant species
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paper birch (Betula papyrifera), tree
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blue birch (Betula ×caerulea), tree
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northern red oak (Quercus rubra), tree
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yellow birch (Betula alleghaniensis), tree
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bigtooth aspen (Populus grandidentata), tree
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striped maple (Acer pensylvanicum), tree
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lowbush blueberry (Vaccinium angustifolium), shrub
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eastern poison ivy (Toxicodendron radicans), shrub
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wavy hairgrass (Deschampsia flexuosa), grass
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rock polypody (Polypodium virginianum), other herbaceous
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bigleaf aster (Eurybia macrophylla), other herbaceous
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marginal woodfern (Dryopteris marginalis), other herbaceous
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wild sarsaparilla (Aralia nudicaulis), other herbaceous
Dominant resource concerns
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Sheet and rill erosion
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Wind erosion
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Plant productivity and health
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Plant structure and composition
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Plant pest pressure
Pathway 1.1a
Community 1.1 to 1.2Competition among species
Context dependence.White pine may be co-dominant in stands that are transitional, with pine giving way to hemlock in time.
State 2
Semi-natural StateShifts in ecological site composition, functionality, and dynamics driven by natural disturbances, processes, and pressures (may have some anthropogenic influences). More research is needed to determine the extent of the Semi-natural state associated with this ecological site.
Dominant resource concerns
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Plant productivity and health
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Plant structure and composition
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Plant pest pressure
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Terrestrial habitat for wildlife and invertebrates
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Aquatic habitat for fish and other organisms
Community 2.1
Invasiveness and Biological IntroductionsIntroduction of invasive species, pathogens, and/or pests resulting in shifts in ecological site composition, functionality, and dynamics. More research is needed to determine the extent of these effects on the semi-natural state associated with this ecological site.
Dominant resource concerns
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Plant productivity and health
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Plant structure and composition
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Plant pest pressure
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Terrestrial habitat for wildlife and invertebrates
State 3
Cultural StateShifts in ecological site composition, functionality, and dynamics that are primary driven by anthropogenic disturbances and pressures (may have some associated natural influences). More research is needed to determine the extent of the cultural state associated with this ecological site.
Dominant resource concerns
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Compaction
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Organic matter depletion
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Pesticides transported to surface water
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Pesticides transported to ground water
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Plant productivity and health
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Plant structure and composition
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Plant pest pressure
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Terrestrial habitat for wildlife and invertebrates
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Aquatic habitat for fish and other organisms
Transition T1A
State 1 to 2Introduction of invasive species, pests, and/or pathogens; alteration of ecological dynamics, functions, and composition, etc.
Key drivers
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Precipitation (decadal scale)
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Temperature (decadal scale)
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Climate
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Nonnative pest presence and/or establishment
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Nonnative disease presence and/or establishment
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Nonnative plant species presence and/or establishment
Key ecosystem services affected
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Nutrient cycling
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Climate regulation: carbon cycling and storage
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Wildlife habitat
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Soil formation
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Animal biodiversity
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Plant biodiversity
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Climate regulation
Transition T1B
State 1 to 3Timber management and harvesting, mechanical landscape alteration, mechanical soil disturbance, planting, seeding
Conservation practices
Clearing and Snagging Land Clearing Spoil Spreading Crop management system on crop land acres recently converted Key drivers
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Mechanical soil disturbance
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Timber management
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Seeding
Key ecosystem services affected
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Fuel
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Recreation
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Wildlife forage
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Climate regulation: carbon cycling and storage
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Wildlife habitat
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Soil formation
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Animal biodiversity
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Plant biodiversity
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Climate regulation
Restoration pathway R2A
State 2 to 1Mechanical, biological, or chemical management of invasive species, pests, and/or pathogens; establishment of native plants through seeding and/or planting
Conservation practices
Prescribed Burning Critical Area Planting Integrated Pest Management (IPM) Environmental Quality Assessment Pathogen Management Invasive Species Pest Management Multi-species Native Perennials for Biomass/Wildlife Habitat Habitat Development for Beneficial Insects for Pest Management Biological suppression and other non-chemical techniques to manage brush, weeds and invasive species Biological suppression and other non-chemical techniques to manage herbaceous weeds invasive species Monitoring and Evaluation Transition T2A
State 2 to 3Timber management and harvesting, landscape clearing, mechanical landscape alteration, mechanical soil disturbance, planting, seeding, cultivation
Conservation practices
Clearing and Snagging Land Clearing Precision Land Forming Land Smoothing Key drivers
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Mechanical soil disturbance
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Timber management
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Seeding
Key ecosystem services affected
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Pollination
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Nutrient cycling
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Wildlife forage
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Climate regulation: carbon cycling and storage
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Wildlife habitat
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Plant biodiversity
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Climate regulation
Restoration pathway R3A
State 3 to 1Restoration of native plant communities, planting, seeding, removal of obstructions or barriers
Conservation practices
Restoration and Management of Natural Ecosystems Native Plant Community Restoration and Management Restoration of Compacted Soils Monitoring and Evaluation Restoration pathway R3B
State 3 to 2Restoration of native plant communities, planting, seeding, removal of obstructions or barriers
Additional community tables
Table 5. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 6. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 7. Community 1.3 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 8. Community 1.4 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 9. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Supporting information
Inventory data references
Future work is needed, as described in a future project plan, to validate the information presented in this provisional ecological site description. Future work includes field sampling, data collection and analysis by qualified vegetation ecologists and soil scientists. As warranted, annual reviews of the project plan can be conducted by the Ecological Site Technical Team. A final field review, peer review, quality control, and quality assurance reviews of the ESD are necessary to approve a final document.
Other references
Comer, P., D. Faber-Langendoen, R. Evans, S. Grawler, C. Josse, G. Kittel, S. Menard, M. Pyne, M. Reid, K. Schultz, K. Snow, and J. Teague. 2003. Ecological Systems of the United States: A Working Classification of U.S. Terrestrial Systems. NatureServe, Arlington, Virginia
Gawler, S. and A. Cutko. 2010. Natural Landscapes of Maine: A Guide to Natural Communities and Ecosystems. Maine Natural Areas Program, Maine Department of Conservation, Augusta, Maine.
NatureServe. 2018. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. NatureServe Explorer (accessed 10 July. 2021).
Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. 2006. Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin. Agricultural Handbook 296
Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Official Soil Series Descriptions. Available online. (accessed 11 Aug. 2021).
Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Soil Climate Research Station Data. Available online. (accessed 23 June. 2021).
Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Soil Survey Geographic (SSURGO) Database for [MLRA 146, Maine]. Available online. (accessed 14 Oct. 2021).
USNVC [United States National Vegetation Classification]. 2017. United States National Vegetation Classification Database V2.01. Federal Geographic Data Committee, Vegetation Subcommittee, Washington DC. Available The U.S. National Vegetation Classification (usnvc.org) (accessed 2 July. 2021).Contributors
Christopher Mann
Jamin JohansonApproval
Greg Schmidt, 5/20/2025
Acknowledgments
Nels Barrett, Nick Butler, and Carl Bickford provided considerable review of this ecological site concept.
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
Author(s)/participant(s) Contact for lead author Date 05/06/2025 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
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Perennial plant reproductive capability:
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