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Ecological site RX143X00Y303

Acidic Swamp

Last updated: 5/20/2025
Accessed: 10/19/2025

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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 (0-5% slopes) near the bottom of watersheds where water saturates both organic soils and coarse-textured mineral soils for most of the year. Soils are deep, poorly- to very poorly-drained and relatively more acidic than other wooded wetlands. The water table is seasonally high (within 18 inches [45 centimeters] of the surface) and typically dries out in late summer and fall. This site may have pit and mound topography, with ponding and organic matter accumulation in the low areas, and drier soil conditions on the mounds where most trees and shrubs are rooted.

The reference state is characterized by black spruce in the overstory with minor inclusions of tamarack, balsam fir, black ash, and grey birch as common associates. Diverse herbs, shrubs, and bryophytes dominate the understory. Logging and altered hydrology are the primary drivers of state change on this site.

Associated sites

RX143X00Y220	Semi-Acidic Peat Wetland Complex The Semi-Acidic Peat Wetland Complex site may occur downslope of the Acidic Swamp site, where water stagnates and lack of available soil oxygen and/or nutrients limits tree growth to less than 20% cover.
RX143X00Y230	Acidic Peat Wetland Complex The Acidic Peat Wetland Complex site may occur downslope of the Acidic Swamp site, where water stagnates and lack of available soil oxygen and/or nutrients limits tree growth to less than 20% cover.

RX143X00Y220

Semi-Acidic Peat Wetland Complex

The Semi-Acidic Peat Wetland Complex site may occur downslope of the Acidic Swamp site, where water stagnates and lack of available soil oxygen and/or nutrients limits tree growth to less than 20% cover.

RX143X00Y230

Acidic Peat Wetland Complex

The Acidic Peat Wetland Complex site may occur downslope of the Acidic Swamp site, where water stagnates and lack of available soil oxygen and/or nutrients limits tree growth to less than 20% cover.

Similar sites

RX143X00Y304	Wet Flat The Wet Flat site occurs in flat areas and is drier than the Acidic Swamp site, with all soils poorly-drained rather than poorly- to very-poorly drained. As a result Wet Flat is characterized by more red spruce, rather than black spruce dominance.

RX143X00Y304

Wet Flat

The Wet Flat site occurs in flat areas and is drier than the Acidic Swamp site, with all soils poorly-drained rather than poorly- to very-poorly drained. As a result Wet Flat is characterized by more red spruce, rather than black spruce dominance.

Table 1. Dominant plant species

Tree	(1) Picea mariana (2) Larix laricina
Shrub	(1) Rhododendron canadense (2) Ledum groenlandicum
Herbaceous	(1) Sphagnum (2) Pleurozium schreberi

Legacy ID

F143XY303ME

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Physiographic features

This ecological site and its associated plant communities occur as freshwater swamps on toeslopes of mountains, where large amounts of water pass through, creating hydric conditions and supporting organic matter accumulation over mineral soils. Slope shape will often range from concave to linear, depending on localized landform, all sites reflecting a seasonal high-water table of 0 to 6 inches (0 to 15 centimeters) during wet periods and up to 24 inches (60 centimeters) during dry periods. This site often exhibits pit and mound topography, a result of years of individual tree tip ups.

Table 2. Representative physiographic features

Hillslope profile	(1) Toeslope
Landforms	(1) Swamp (2) Outwash terrace
Runoff class	Very low to medium
Flooding frequency	None
Ponding duration	Brief (2 to 7 days) to very long (more than 30 days)
Ponding frequency	Occasional to frequent
Elevation	10 – 2,800 ft
Slope	2%
Ponding depth	6 in
Water table depth	6 in
Aspect	Aspect is not a significant factor

Table 3. Representative physiographic features (actual ranges)

Runoff class	Very low to high
Flooding frequency	None
Ponding duration	Very brief (4 to 48 hours) to very long (more than 30 days)
Ponding frequency	None to frequent
Elevation	Not specified
Slope	5%
Ponding depth	15 in
Water table depth	24 in

Climatic features

As the northernmost MLRA in the region, this site experiences frigid and snowy winters, warm rainy summers, and a relatively short five to six month growing season. Precipitation is considerably constant from month to month; however, areas of 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.

Table 4. Representative climatic features

Frost-free period (characteristic range)	79-90 days
Freeze-free period (characteristic range)	118-125 days
Precipitation total (characteristic range)	41-43 in
Frost-free period (actual range)	79-98 days
Freeze-free period (actual range)	117-129 days
Precipitation total (actual range)	40-44 in
Frost-free period (average)	86 days
Freeze-free period (average)	122 days
Precipitation total (average)	42 in

Characteristic range

Actual range

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Figure 1. Monthly precipitation range

Characteristic range

Actual range

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Figure 2. Monthly minimum temperature range

Characteristic range

Actual range

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Figure 3. Monthly maximum temperature range

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Figure 4. Monthly average minimum and maximum temperature

Figure 5. Annual precipitation pattern

Figure 6. Annual average temperature pattern

Climate stations used

(1) LAKE PLACID 2 S [USC00304555], Lake Placid, NY
(2) NEWCOMB [USC00305714], Newcomb, NY
(3) EUSTIS [USC00172700], Eustis, ME
(4) PLYMOUTH [USC00276945], Campton, NH
(5) MORRISVILLE 4 SSW [USC00435376], Morrisville, VT

Influencing water features

Large amounts of water enter this site as run-on from the watershed above. Gentle slopes allow water to pass laterally through the soil on this site before exiting downslope to even wetter, flatter sites below. Despite the sandy soils through which water flows freely, water saturates this site for much of the year. However, due to the porous nature of the substrate, the water table can fluctuate greatly during the growing season, permitting soil aeration needed to sustain its characteristic plant community.

Wetland description

Classification System: Cowardin
System: Palustrine
Subsystem: NA
Class: Forested Wetlands
Subclass: Needle-leaved Evergreen

Soil features

Soils are dominantly very poorly drained with some areas poorly drained. These soils form in coarse outwash or till that was re-worked by glacial meltwaters. Typical soils will have 2 to 10 inches (5 to 25 centimeters) of organic mucky or peat over sandy or coarse-loamy mineral deposits. A densely compacted horizon is typically absent from these soils. These soils may or may not have large amounts of rock in the surface or subsurface horizons.

Representative soils include the Tahawus (Histic Humaquepts) and Searsport (Histic Humaquepts) series. Other soils such as the Kinsman (Typic Endoaquods), Naumburg (Typic Endoaquods), and Tughill (Typic Endoaquepts) series may be locally representative in some cases.

Table 5. Representative soil features

Parent material	(1) Glaciolacustrine deposits (2) Glaciofluvial deposits (3) Outwash (4) Till – granite and gneiss
Surface texture	(1) Mucky, peaty sand
Family particle size	(1) Sandy
Drainage class	Very poorly drained
Permeability class	Slow to moderate
Soil depth	80 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	2%
Available water capacity (0-40in)	3.7 – 7 in
Soil reaction (1:1 water) (0-40in)	4.6 – 6.8
Subsurface fragment volume <=3" (0-40in)	6%
Subsurface fragment volume >3" (0-40in)	4%

Table 6. Representative soil features (actual values)

Drainage class	Very poorly drained to poorly drained
Permeability class	Very slow to moderate
Soil depth	80 in
Surface fragment cover <=3"	2%
Surface fragment cover >3"	2%
Available water capacity (0-40in)	2 – 7 in
Soil reaction (1:1 water) (0-40in)	3.5 – 7
Subsurface fragment volume <=3" (0-40in)	30%
Subsurface fragment volume >3" (0-40in)	20%

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 et al., 2003) and localized associations provided by the New York Natural Heritage Program (Edinger et al., 2014), Maine Natural Areas Program (Gawler and Cutko, 2010), New Hampshire Natural Heritage Program (Sperduto and Nichols, 2011), and Massachusetts Division of Fisheries and Wildlife (Swain, 2020).

The reference state is a boreal softwood dominated forest where black spruce (Picea mariana) often makes up a dominant component in the canopy. Other trees may include tamarack, balsam fir, red maple, and / or white pine, but will often only be present in small amounts. The understory is diverse with sphagnum moss, creeping snowberry, and three-seed sedge common. These swamps are characterized by acidic, waterlogged conditions, with trees rooted primarily in the poorly drained soil mounds than the very poorly drained depressions.

Altered hydrology, in the form of ponding or draining, can greatly alter the ecological functioning of this site. While these trees can tolerate high seasonal high-water tables, higher than normal water levels will reduce growth and eventually kill trees. This is often seen through beaver damming and road construction and may transition the reference forested condition through a variety of communities including open marsh grasses and emergent vegetation. Removal of dams and man-made structures that restores hydrologic function leads to natural succession by emergent wetland plants, herbaceous plants, shrubs, and eventually spruce re-establishment. Draining and ditching along with tree cover removal can convert the site to hayfield and pasture with varying degrees of ponding, depending on the extent of hydrological alteration.

Large scale logging is typically not common due to the poor productivity and wetness of this site, limiting small scale harvesting to very dry years or during the winter months where soil and ground disturbances may be minimized. Logging operations can significantly alter the structure and function of these swamps, causing shifts in vegetative composition, hydrologic function, and ecosystem services. Selective harvesting, thinning, and shelterwood cuts will not generally shift the site to a different state but may help promote forest regeneration and result in a temporary increase in understory shrubs and herbs. Clear cutting may have the largest impact on these communities, with potential disruption of water retention, soil surface cover and altered groundwater flow. In some cases, clearcutting can be used as a surrogate to fire, promoting rapid growth of seedlings after the disturbance.

Fire is typically not a dominant risk in these communities due to their inherent wetness and general lack of ladder fuels, however fire of any severity will generally kill black spruce due to the arrangement of cones and branches promoting easy ignition. Black spruce regeneration and establishment occurs within 5 years post fire, with more favorable seedbeds including mineral and organic soil where the moss and lichen layers have burned off (Freyer 2014).

State and transition model

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Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Black Spruce Swamps

2. Beaver Meadows / Transitional Marshes

3. Converted Cultural State

4. Freshwater Emergents and Open Water

T1A	-	Variable increase in soil wetness (natural or anthropogenic)
T1B	-	Anthropogenic drainage, land clearing, cultivation of pasture grasses and / or legumes
T2A	-	Decrease in soil wetness (natural or anthropogenic)
T2B	-	Intense increase in soil wetness (natural or anthropogenic)
T3A	-	Long-term agricultural abandonment
T4A	-	Decrease in soil wetness (natural or anthropogenic)

State 1 submodel, plant communities

1.1. Black Spruce Forest

1.2. Temporary Herbaceous / Open Shrubland

1.3. Early Seral Forest

1.4. Mixed Canopy Black Spruce Swamp

1.1A	-	Patch cut, clearcut, or blowdown that increases soil wetness and light availability
1.1B	-	Shelterwood cut, selective harvesting, forest thinning
1.2A	-	Spruce regeneration (<20years)
1.3A	-	Patch cut, clearcut, or blowdown that increases soil wetness and light availability
1.3B	-	Time (20-100years), spruce growth
1.4A	-	Time (>100years)
1.4B	-	Patch cut, clearcut, or blowdown that increases soil wetness and light availability
1.4B	-	Shelterwood cut, selective harvesting, forest thinning

State 2 submodel, plant communities

2.1. Sedges and Wet Herbaceous Meadows

2.2. Alder and Tall Shrublands

2.1A	-	Time, natural successional allowing for the establishment and dominance (greater than 50 percent cover) of shrubs

State 3 submodel, plant communities

3.1. Improved Pasture Grasses and Legumes

3.2. Herbaceous and Shrubby “Old Field”

3.1A	-	Reduced or eliminated grassland management operations that allows for succession of predominantly invasive or incursive shrubs and trees
4.2	-	Removal of undesirable species via management practices (mechanical, chemical, biological), regular maintenance and management of grassland operations

State 4 submodel, plant communities

4.1. Freshwater Emergents

4.2. Open Water

4.1A	-	Increase in long-term hydrology
4.2	-	Decrease in long-term hydrology

State 1
Black Spruce Swamps

These are softwood dominated boreal forests most often comprised of mature black spruce (Picea mariana) found on shallow organic over mineral soils. The canopy is often a pure stand of black spruce that is often closed to broken. Other trees that are found in the canopy include balsam fir (Abies balsamea) or tamarack (Larinx laricina). Tall shrubs are generally absent, low shrubs and forbs are often sparse to locally abundant (greater than 30 percent cover). Bryophytes are the dominant groundcover, covering both hummocks and hollows. Natural disturbances by wind create tip-ups of individual trees or small groups of trees that are attributed to the hummock and hollows microtopography. Changes in light availability and soil wetness are the dominant drivers for these communities, with logging being the main factor attributable to large scale changes.

Dominant plant species

black spruce (Picea mariana), tree
balsam fir (Abies balsamea), tree
tamarack (Larix laricina), tree
blueberry (Vaccinium), shrub
bog Labrador tea (Ledum groenlandicum), shrub
sheep laurel (Kalmia angustifolia), shrub
rhodora (Rhododendron canadense), shrub
bunchberry dogwood (Cornus canadensis), other herbaceous
bluebead (Clintonia borealis), other herbaceous
Canada mayflower (Maianthemum canadense), other herbaceous
threeleaf goldthread (Coptis trifolia), other herbaceous
sphagnum (Sphagnum), other herbaceous

Community 1.1
Black Spruce Forest

Mature black spruce dominates the canopy and will often be greater than 65% cover, creating dark and cool understory conditions. Balsam fir and tamarack can be present as codominant species but will often but minor components. Tall shrub cover is typically sparse and consist primarily of ericaceous low shrubs and forbs. Graminoids tend to be sparse to absent. Localized minerotropic areas may contain a more diverse herbaceous layer. Bryophytes form a near continuous groundcover and will cover hummocks and hollows. Within the Northeast US, this community type correlates to Maine’s “Spruce-Larch Woodland Bog” concept (Gawler and Cutko 2010), New Hampshire’s “Black Spruce Swamp” and “Mountain Holly-Black Spruce Wooded Fen” concepts (Sperduto and Nichols 2012), New York’s “Black Spruce-Tamarack Bog” concept (Edinger et al. 2014), and Vermont’s “Black Spruce Swamp” concept (Thompson, Sorenson, and Zaino 2019). This correlates with NatureServes ‘Picea mariana - (Larix laricina) / Ledum groenlandicum / Sphagnum spp. Swamp Forest' Association (CEGL005271).

Dominant plant species

black spruce (Picea mariana), tree
balsam fir (Abies balsamea), tree
tamarack (Larix laricina), tree
leatherleaf (Chamaedaphne calyculata), shrub
creeping snowberry (Gaultheria hispidula), shrub
bog laurel (Kalmia polifolia), shrub
bog Labrador tea (Ledum groenlandicum), shrub
blueberry (Vaccinium), shrub
sheep laurel (Kalmia angustifolia), shrub
catberry (Ilex mucronata), shrub
rhodora (Rhododendron canadense), shrub
woollyfruit sedge (Carex lasiocarpa), grass
threeseeded sedge (Carex trisperma), grass
tussock cottongrass (Eriophorum vaginatum var. spissum), grass
bunchberry dogwood (Cornus canadensis), other herbaceous
bluebead (Clintonia borealis), other herbaceous
threeleaf goldthread (Coptis trifolia), other herbaceous
Canada mayflower (Maianthemum canadense), other herbaceous
cinnamon fern (Osmunda cinnamomea), other herbaceous
dicranum moss (Dicranum polysetum), other herbaceous
sphagnum (Sphagnum), other herbaceous
Schreber's big red stem moss (Pleurozium schreberi), other herbaceous

Community 1.2
Temporary Herbaceous / Open Shrubland

This condition represents the herbaceous and shrublands of temporary dominance following localized disturbances. This can be the result of large-scale disturbances such as clearcutting or naturalized mortality from wind events. Increased light availability allows for the dominance of shrubs and forbs while available tree saplings being to grow into the overstory. The groundcover of mosses may or may not be abundant depending on the type and intensity of the disturbance. Operation of heavy machinery can create ruts that may persist for many years and can alter surface water hydrology, transitioning this phase to another state over time.

Dominant plant species

leatherleaf (Chamaedaphne calyculata), shrub
creeping snowberry (Gaultheria hispidula), shrub
bog laurel (Kalmia polifolia), shrub
bog Labrador tea (Ledum groenlandicum), shrub
blueberry (Vaccinium), shrub
catberry (Ilex mucronata), shrub
rhodora (Rhododendron canadense), shrub
blackberry (Rubus), shrub
rose (Rosa), shrub
honeysuckle (Lonicera), shrub
buckthorn (Rhamnus), shrub
sedge (Carex), grass
tussock cottongrass (Eriophorum vaginatum var. spissum), grass
bunchberry dogwood (Cornus canadensis), other herbaceous
bluebead (Clintonia borealis), other herbaceous
threeleaf goldthread (Coptis trifolia), other herbaceous
threeleaf false lily of the valley (Maianthemum trifolium), other herbaceous
cinnamon fern (Osmunda cinnamomea), other herbaceous
sphagnum (Sphagnum), other herbaceous
Schreber's big red stem moss (Pleurozium schreberi), other herbaceous
dicranum moss (Dicranum polysetum), other herbaceous

Community 1.3
Early Seral Forest

Seedling and sapling regeneration of black spruce is abundant and may be intermixed with other species such as red maple, tamarack, black cherry, black ash, or balsam fir. Faster growing trees such as balsam fir may temporarily outcompete other species. While this community may not consist of trees in a similar size class, these communities will typically be in a single age class. Species will typically be less than 50 years old and will range up to 15 feet (5 meters) in height. Loss of the characteristic abundant groundcover of mosses may be present, with varying amounts of woody and herbaceous litter present. Low shrubs such as highbush blueberry and raspberries may be present.

Community 1.4
Mixed Canopy Black Spruce Swamp

This successional phase consists of a mixed canopy of black spruce and older early successional species such as tamarack, balsam fir, black ash, paper birch, and red maple. Hardwoods and balsam fir will begin to die out in this state but still may be canopy dominants before reverting to a mature black spruce dominant forest. The shrub component tends to decrease with increasing overstory density, reflecting conditions similar to the reference condition.

Pathway 1.1A
Community 1.1 to 1.2

This may occur through intensive harvesting practices such as clearcutting for pulp and lumber. Immediate loss of mature canopy trees increases light availability for understory vegetation and disturbs the seedbank, shifting dominant species composition and structure. Natural mortality from windstorms, insects, diseases, ice or snow damage may also reflect a similar transition, opening the canopy and allowing for the temporary dominance of grasses and forbs, but will leave behind large pieces of woody material for nurse logs. Loss of characteristic groundcover mosses is common as more light availability and altered soil conditions favor faster-growing species. Harvesting during winter months is recommended to prevent extensive rutting and hydrologic instability that may lead to issues such as erosion, loss of moisture retention, and changes in groundwater flow.

Pathway 1.1B
Community 1.1 to 1.3

This transition can occur through shelterwood strip cuts or selective harvesting, in which the mature black spruce canopy is cleared, allowing for new seedlings to grow under the shelter of the remaining trees before harvesting the remaining trees. This is often done in spruce swamps due to it being less intensive than clear cutting and may cause less disruption to the swamp’s hydrology and vegetation, preserving much of its original structure and function. This may have a minimal impact on the overall canopy composition while promoting the growth of saplings. Harvesting during winter months is recommended and will differ from clearcutting methods through the limited disturbance to the local hydrology.

Pathway 1.2A
Community 1.2 to 1.3

This transition can occur if the basic requirements for tree regeneration are met, primarily an adequate seed supply, proper seedbed, and light, temperature, and moisture conditions are conductive for seed germination and survival. This transition will often occur in less than but no greater than 20 years post-canopy disturbance. Planting black spruce can help accelerate the restoration of the natural vegetation of the swamp.

Pathway 1.3A
Community 1.3 to 1.2

This may occur through intensive harvesting practices such as clearcutting for pulp. Immediate loss of regenerating trees increases light availability for understory vegetation and disturbs the seedbank, shifting dominant species composition and structure. Natural mortality from windstorms, insects, diseases, ice or snow damage may also reflect a similar transition, opening the canopy and allowing for the temporary dominance of grasses and forbs, but will leave behind large pieces of woody material for nurse logs. Loss of characteristic groundcover mosses is common as more light availability and altered soil conditions favor faster-growing species. Harvesting during winter months is recommended to prevent extensive rutting and hydrologic instability that may lead to issues such as erosion, loss of moisture retention, and changes in groundwater flow.

Pathway 1.3B
Community 1.3 to 1.4

This transition will occur over time, typically greater than 20 years but less than 100 years into a stand’s lifecycle. The early successional stand will thin in density either naturally (treefall, disease, etc.) or via human interference (forest stand improvement [FSI]). Tree height will surpass an average of 15 feet and greater than 1.6 inches diameter at breast height (DBH) along with more spaced trees with intermediate understory regeneration and development. Thinning through FSI methods can allow for the regeneration of understory vegetation, including saplings, while encouraging the growth of the desired species. FSI during winter months is recommended and will differ from clearcutting or selecting harvesting methods through the limited disturbance to the local hydrology.

Pathway 1.4A
Community 1.4 to 1.1

This transition will over time, often greater than 100 years, in which the main stand remains relatively undisturbed. This will allow the black spruce stand to mature in its size and height classes, creating a more uneven aged stand with a well-developed overstory and a dark, cool understory that limits regeneration. This transition may be assisted with forest stand improvement practices. Black spruce will become the canopy dominant, and the understory will reflect more variation in microtopography (hummocks and hollows) due to natural disturbance tip ups.

Pathway 1.4B
Community 1.4 to 1.2

This may occur through intensive harvesting practices such as clearcutting for pulp and lumber. Immediate loss of regenerating trees increases light availability for understory vegetation and disturbs the seedbank, shifting dominant species composition and structure. Natural mortality from windstorms, insects, diseases, ice or snow damage may also reflect a similar transition, opening the canopy and allowing for the temporary dominance of grasses and forbs, but will leave behind large pieces of woody material for nurse logs. Loss of characteristic groundcover mosses is common as more light availability and altered soil conditions favor faster-growing species. Harvesting during winter months is recommended to prevent extensive rutting and hydrologic instability that may lead to issues such as erosion, loss of moisture retention, and changes in groundwater flow.

Pathway 1.4B
Community 1.4 to 1.3

State 2
Beaver Meadows / Transitional Marshes

These are graminoid and shrub dominated wetlands that are typical successional communities after an alteration to the surrounding landscape increases the local hydroperiods. This is most often the result of beaver damming but can be the result of anthropogenic influences such as building of roads and man-made dams as well. This state may persist indefinitely or may be seen as a transitional community and will depend on the surrounding hydrologic regime. It can be identified by the presence of the sandy or coarse-loamy textures underneath mucky organic soils, compared to other sites which may have deeper organic soils or a root restrictive layer. Standing dead snags may or may not be present depending on time since hydrological change.

Dominant plant species

alder (Alnus), shrub
sedge (Carex), grass
reedgrass (Calamagrostis), grass
bulrush (Scirpus), grass

Community 2.1
Sedges and Wet Herbaceous Meadows

These are graminoid dominant wetlands comprised most often of sedges and grasses in a monotypic or mixed stand of often greater than 50 percent cover. Forbs will often be present in lower amounts and locally abundant but not dominant. Trees, shrubs, and other woody species will often be sparse to absent, occurring as stunted individuals found on microhighs created from past tip ups. The ground cover typically consists of herbaceous litter mixed with bryophytes, which is usually sparse but may occasionally reach over 50 percent cover. Changes in dominant species will often be dependent on slight differences in the hydroperiod and the presence or absence of a viable seedbank.

Dominant plant species

upright sedge (Carex stricta), grass
blister sedge (Carex vesicaria), grass
Northwest Territory sedge (Carex utriculata), grass
bluejoint (Calamagrostis canadensis), grass
rattlesnake mannagrass (Glyceria canadensis), grass
three-way sedge (Dulichium arundinaceum), grass
common rush (Juncus effusus), grass
rice cutgrass (Leersia oryzoides), grass
woolgrass (Scirpus cyperinus), grass
swamp milkweed (Asclepias incarnata), other herbaceous
eastern marsh fern (Thelypteris palustris), other herbaceous
spotted joe pye weed (Eutrochium maculatum), other herbaceous
marsh bellflower (Campanula aparinoides), other herbaceous
royal fern (Osmunda regalis), other herbaceous
purple marshlocks (Comarum palustre), other herbaceous
thoroughwort (Eupatorium), other herbaceous
sphagnum (Sphagnum), other herbaceous

Community 2.2
Alder and Tall Shrublands

These are shrub dominated swamps and will often be found in a steady state or as along a successional pathway to another community type. The vegetation is dominated by tall shrubs, most often speckled alder (Alnus incana) forming dense, nearly impenetrable thickets. Where alder is not dominant, other wetland shrubs can be found. The herbaceous layer contains forms and graminoids reflective of the surrounding marsh if seen as an inclusion or the relict marsh if seen as a successional community. Then ground layer will often be highly variable depending on the presence or absence of canopy openings, with herbaceous species being denser in canopy gaps. If seen as a transitional community along a successional path from a previously flooded beaver meadow back to a forested wetland, scattered stunted trees and saplings may be found in the alder stands.

Dominant plant species

black spruce (Picea mariana), tree
gray alder (Alnus incana), shrub
hazel alder (Alnus serrulata), shrub
redosier dogwood (Cornus sericea), shrub
American red raspberry (Rubus idaeus), shrub
steeplebush (Spiraea tomentosa), shrub
viburnum (Viburnum), shrub
blueberry (Vaccinium), shrub
parasol whitetop (Doellingeria umbellata), other herbaceous
spotted joe pye weed (Eutrochium maculatum), other herbaceous
jewelweed (Impatiens capensis), other herbaceous
northern bugleweed (Lycopus uniflorus), other herbaceous
sensitive fern (Onoclea sensibilis), other herbaceous
cinnamon fern (Osmunda cinnamomea), other herbaceous
eastern marsh fern (Thelypteris palustris), other herbaceous
violet (Viola), other herbaceous
sphagnum (Sphagnum), other herbaceous

Pathway 2.1A
Community 2.1 to 2.2

This transition may occur in a beaver meadow with slight fluctuations in the hydroperiod and the establishment of tall shrubs, especially alder (Alnus spp.).

State 3
Converted Cultural State

This state represents a once forested area now cleared for pasture. This will typically only occur on gentler slopes (<15 percent) due to potential for water erosion. Pasture vegetation can consist of grasses, legumes, other forbs, shrubs or a mixture. Many of these forages are introduced, having originally come from areas in other states or continents. Overgrazed pastures can lead to soil compaction and numerous bare spots, which may then become focal points of accelerated erosion and colonization sites of undesirable plants or weeds. In these systems, water control structures may be used to prevent excess water in the fields and historical drainage and cultivation of this site may lead to the loss of the mucky organic surface texture.

Dominant plant species

orchardgrass (Dactylis glomerata), grass
reed canarygrass (Phalaris arundinacea), grass
timothy (Phleum pratense), grass
smooth brome (Bromus inermis), grass
tall fescue (Schedonorus arundinaceus), grass

Community 3.1
Improved Pasture Grasses and Legumes

This community phase represents commonly planted forage species on pastureland and hayland. The suite of plants established on any given site may vary considerably depending upon purpose, management goals, and usage (e.g., horse vs. cattle). Most systems include a mixture of grasses and legumes that provide forage throughout the growing season. Several additional plants and/or species combinations maybe present depending on the objectives and management approaches of the land manager/owner.

Dominant plant species

timothy (Phleum pratense), grass
sweet vernalgrass (Anthoxanthum odoratum), grass
Kentucky bluegrass (Poa pratensis), grass
orchardgrass (Dactylis glomerata), grass
smooth brome (Bromus inermis), grass
fescue (Festuca), grass
perennial ryegrass (Lolium perenne), grass
redtop (Agrostis gigantea), grass
festulolium (×Festulolium), grass
alfalfa (Medicago sativa), other herbaceous
clover (Trifolium), other herbaceous
milkvetch (Astragalus), other herbaceous
bedstraw (Galium), other herbaceous

Community 3.2
Herbaceous and Shrubby “Old Field”

This phase represents a more degraded phase for livestock. While some utilization of desirable pasture plants will occur, undesirable species are prolific. As undesirable pasture species grow, desirable pasture grasses and forbs will decrease in cover. Small trees representative of the reference condition (often early successional species) is often present but do not form great amounts of canopy cover.

Dominant plant species

goldenrod (Solidago), other herbaceous
cowparsnip (Heracleum), other herbaceous
yellow rattle (Rhinanthus), other herbaceous
buttercup (Ranunculus), other herbaceous
hawkweed (Hieracium), other herbaceous
iris (Iris), other herbaceous
sagebrush (Artemisia), other herbaceous

Pathway 3.1A
Community 3.1 to 3.2

This transition may occur through the absence or mismanagement of pasture or haylands may result with the increase in undesirable species and decrease in desirable species.

Pathway 4.2
Community 3.2 to 3.1

This transition may occur through management practices via mechanical, chemical, or biological means may be used to remove undesirable pasture or hayland species.

State 4
Freshwater Emergents and Open Water

These are wetlands of emergent vegetation and areas of open water, often reflecting slightly higher seasonal high-water tables or increased long-term hydroperiods. Hydrologic regimes are often the longest in this state, with long-term or permanent inundation influencing the development of freshwater emergent species. Organic soils are often deepest in these states but may often include shallow organics or high organic content mineral soils. These communities will often form near monocultures and be so dense that germination of other species is limited.

Dominant plant species

cattail (Typha), other herbaceous
pickerelweed (Pontederia), other herbaceous
arrowhead (Sagittaria), other herbaceous

Community 4.1
Freshwater Emergents

These are emergent species that dominant the shallowly ponded areas. Dominant species will vary based on the depth and duration of ponding and will often form dense monocultures so that germination of other species can be limited.

Dominant plant species

cattail (Typha), grass
reed (Phragmites), grass
bulrush (Scirpus), grass
pickerelweed (Pontederia), other herbaceous
arrowhead (Sagittaria), other herbaceous

Community 4.2
Open Water

This phase describes the impact of increased hydroperiods the results in a permanently inundated condition. Standing dead snags may be present and indicative of a once forested community.

Pathway 4.1A
Community 4.1 to 4.2

This transition may occur through increases in long-term hydrology that causes standing water, kills existing vegetation, and prevents germination of new species. Ponding may be year-round. This may occur naturally (beaver dams) or anthropogenically.

Pathway 4.2
Community 4.2 to 4.1

Decrease in long-term hydrology that causes water levels to drop and freshwater emergent species to germinate in shallow ponding conditions. This may occur naturally (beaver dam removal) or anthropogenically.

Transition T1A
State 1 to 2

This transition may occur through variable increases in soil wetness, often because of natural or anthropogenic influence such as beaver or man-made dams. This may also be intensified by extensive harvesting, which reduces canopy cover and water use by trees, promoting graminoids and shrubs to become dominant. In dammed areas, existing trees may be killed and standing dead snags will be remnant in the overstory.

Transition T1B
State 1 to 3

The reference state transitions to the managed grassland state with the clearing of woody vegetation and the establishment of pasture grasses and legumes. Water control structures may have been used in historically transitioned sites to drain excess water from the site and make it more suitable for pasture species. Current transition from the reference state to a converted cultural state may not be suitable following local, state, and federal laws.

Transition T2A
State 2 to 1

This transition may occur through decreases in soil wetness, often due to the removal of beaver or man-made dams. Lower seasonal high-water tables and seasonal fluctuation can allow for regeneration and sapling establishment.

Transition T2B
State 2 to 4

This transition may occur through intense increase in soil wetness, often because of natural or anthropogenic influence such as beaver or man-made dams. In dammed areas, existing trees may be killed and standing dead snags will be remnant in the overstory. Depending on the average depth of standing water, freshwater emergent vegetation may become dominant.

Transition T3A
State 3 to 1

This transition may occur following long-term agricultural abandonment.

Transition T4A
State 4 to 2

Additional community tables

Interpretations

Animal community

**DRAFT**
The following information is provided from University of New Hampshire’s “Dirt to Trees to Wildlife”. Asterisks denotes Species of Greatest Conservation Need and hyperlinks will take you to recommendations specific to those species.

Common animals found in Spruce-Fir Forest Types at ANY elevation may include:

Snowshoe hare (Lepus americanus), Red squirrel (Sciurus vulgaris), Southern red-backed vole (Myodes gapperi), Long-tailed shrew (Sorex dispar)*, American marten (Martes americana)*, Boreal chickadee (Poecile hudsonicus), Dark-eyed junco (Junco hyemalis), Pine siskin (Spinus pinus), Spruce grouse (Canachites canadensis )*, and Red-breasted nuthatch (Sitta canadensis).

Common animals found in Spruce-Fir Forest Types at low-elevation (generally below 2,500 feet) only may include

Northern flying squirrel (Glaucomys sabrinus), Deer mouse (Peromyscus maniculatus), Hoary bat (Lasiurus cinereus)*, Tri-colored bat (Perimyotis subflavus)*, Little brown bat (Myotis lucifugus)*, Silver-haired bat (Lasionycteris noctivagans)*, Northern long-eared bat (Myotis septentrionalis)*, Indiana bat (Myotis sodalis)*, Red bat (Lasiurus borealis)*, Red fox (Vulpes vulpes), Bobcat (Lynx rufus)*, Moose (Alces alces)*, Bay-breasted warbler (Setophaga castanea)*, Blackburnian warbler (Setophaga fusca), Cape May warbler (Setophaga tigrina)*, Common goldeneye (Bucephala clangula), Magnolia warbler (Setophaga magnolia), Olive-sided flycatcher (Contopus cooperi)*, Purple finch (Haemorhous purpureus)*, Rusty blackbird (Euphagus carolinus)*, Sharp-shinned hawk (Accipiter striatus)*, Swainsons thrush (Catharus ustulatus), Three-toed woodpecker (Picoides dorsalis)*, Yellow-bellied flycatcher (Empidonax flaviventris), Blackpoll warbler (Setophaga striata), Blue-headed vireo (Vireo solitarius), Northern parula (Setophaga americana), evening grosbeak (Coccothraustes vespertinus), Northern saw-whet owl (Aegolius acadicus), Hermit thrush (Catharus guttatus), Merlin (Falco columbarius), and the Nashville warbler (Leiothlypis ruficapilla).

Silvicultural recommendations for managing wildlife habitat:
-Use uneven-aged management - group selection with group sizes of less than 1 acre.
-Rotation age - 120 years
-Entry cycle every 15 to 20 years
-Avoid entry during nesting season (April to June)
-Whole-tree harvest or cut-to-length is preferred.

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 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

Bromley, S. W. (1935). The original forest types of southern New England. Ecological Monographs, 5(1), 61-89.

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

Edinger, G. J., D. J. Evans, S. Gebauer, T. G. Howard, D. M. Hunt, and A. M. Olivero (editors). 2014. Ecological Communities of New York State. Second Edition. A revised and expanded edition of Carol Reschke’s Ecological Communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation, Albany, NY.

Fryer, Janet L. 2014. Picea mariana. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).

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.

Golet, F. C., & Allen, J. A. (1993). Ecology of red maple swamps in the glaciated Northeast: A community profile (Vol. 12). US Department of the Interior, Fish and Wildlife Service.

Heinselman, M. L. (1957). Silvical characteristics of black spruce (Picea mariana) (No. 45). Lake States Forest Experiment Station, Forest Service, US Department of Agriculture.

Locky, D. A., Bayley, S. E., & Vitt, D. H. (2005). The vegetational ecology of black spruce swamps, fens, and bogs in southern boreal Manitoba, Canada. Wetlands, 25(3), 564-582.

NatureServe. 2021. NatureServe Explorer: An online encyclopedia of life [web application]. NatureServe, Arlington, Virginia. https://explorer.natureserve.org/. (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 141, Maine]. Available online. (accessed 14 Oct. 2021).

Sorenson, E., Popp, R., Lew-Smith, M., Engstrom, B., Lapin, M., Ferguson, M., & Waterbury, V. (2004). Hardwood swamps of vermont: distribution, ecology, classification, and some sites of ecological significance. Nongame and Natural Heritage Program and Vermont Fish and Wildlife Department, 55.

Sorenson, E., Popp, R., Engstrom, B., Lapin, M., Farrell, D., & Waterbury, V. (2009). Softwood swamps of Vermont: Distribution, ecology, classification, and some sites of ecological significance. Nongame and Natural Heritage Program, Vermont Fish and Wildlife Department, Montpelier, Vermont.

Sperduto, D.D. and William F. Nichols. 2011. Natural Communities of New Hampshire. 2nd Ed. NH Natural Heritage Bureau, Concord, NH. Pub. UNH Cooperative Extension, Durham, NH.

Swain, P. C. 2020. Classification of the Natural Communities of Massachusetts. Massachusetts Division of Fisheries and Wildlife, Westborough, MA

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

Jack Ferrara, Revisions 2025
Christopher Mann, Revisions 2022
Jamin Johanson, Original Author 2016

Approval

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	04/21/2025
Approved by	Greg Schmidt
Approval date
Composition (Indicators 10 and 12) based on	Annual Production