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 mature coniferous forest primarily dominated by northern white cedar (Thuja occidentalis) on gently sloping hillsides, or at slope bases, with significant seepage of groundwater.
Logging is historically the greatest source of disturbance. These stands are relative free of serious insect injury as well as being resistant to decay, making them high in value for wood products that comes in contact with water and soil, such as fence posts, shingles, and paneling. This wood has historically been popular for log cabins because of good insulating qualities. Due to the wet nature of these soils, this site is particularly vulnerable to lasting disturbance when logging practices during the growing season churn and rut the surface soils. For this reason, this site is typically harvested when the ground is frozen. Harvests have often targeted spruce removal, though northern white cedar is also often taken from these areas. Selective harvests do not generally convert the site to a different state but do result in a temporary increase in understory shrubs and herbs. Clearcutting and shelterwood strips are currently recommended for harvesting mature stands of northern white cedar and reproducing new ones (Carey 1993). Difficulty has been identified in regenerating these species after harvesting due to its forage value to white tailed deer. Northern white cedar are slow growing species, and the seedlings (less than 7 ft tall) are often damaged by heavy browsing.
Natural disturbances will include wind, ice, and snow damage that create natural canopy gaps from individual or group tree fall, leading to greater sunlight exposure and temporary increase in shrub and forb cover. In areas of intense groundwater seepage, highly diverse areas of forbs and grasses can persist for extended periods of time, particularly in areas where emerging groundwater creates a saturated and unstable rooting substrate that does not support tall trees. Herbivory on seedlings and pole trees may cause extensive damage in times where low forage is available elsewhere, and high browse lines are often seen on larger northern white cedar trees.
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 cedar 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.
While cedar is generally considered as shade tolerant, it is not as tolerant as balsam fir, sugar maple, red maple, and black ash. Seedlings are often intermediate in shade tolerance and can survive severe suppression for several years but will die if not eventually released in the canopy. Successional replacement is often seen on a tree-by-tree basis, where cedar saplings in the understory are released when a mature cedar dies, but major disturbances may accelerate the replacement of cedar with more shade tolerant species.
Fire is typically not a dominant risk in these communities due to their inherent wetness, but they are highly susceptible due to their thin bark, shallow roots, and high oil content (Carey 1993, Curtis 1946). Cedar regeneration may become better established by seed on recently burned sites if a seed source is nearby and the exposed soil remains moist.
State 1
Cedar Seepage Swamps
These are softwood dominated forests most often comprised of mature northern white cedar (Thuja occidentalis) found on shallow organic over dense till soils. The canopy is often a pure stand of cedar (up to 95 percent abundance) and can be somewhat open but is more often closed. Minor inclusions of hardwoods may be present. 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. Changes in light availability and soil wetness are the dominant drivers for these communities, with logging being the main factor attributable to this.
Community 1.1
Late Successional Seepage Cedar Forest
Mature northern white cedar is dominant in the closed canopy (greater than 60 percent to over 90 percent canopy cover) and will often create a dark, cool forest floor. A patchy shrub layer is often present with a highly diverse herbaceous layer (greater than 50 percent cover) over a nearly continuous cover of bryoids. Hummocks and hollows are common microtopographic features of this site, indicating years of tip ups due to the highly saturated and shallow root restriction. Other species such as red spruce, yellow birch, red maple, black ash, and balsam fir may be present in small amounts but not dominant.
Within the Northeast US, this community type correlates to Maine’s “Evergreen Seepage Forest” concept (Gawler and Cutko 2010), New Hampshire’s “Northern White Cedar Seepage Forest” concept (Sperduto and Nichols 2012), New York’s “Northern White Cedar Swamp” concept (Edinger et al. 2014), and Vermont’s “Northern White Cedar Sloping Seepage Forest” concept (Thompson, Sorenson, and Zaino 2019). This correlates with NatureServes ‘Thuja occidentalis – (Picea rubens)/ Tiarella cordifolia Swamp Forest ' Association (CEGL006175) and LandFires’ ‘Acadian – Appalachian Conifer Seepage Forest’ concept (CES201.576).
Dominant plant species
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arborvitae (Thuja occidentalis), tree
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balsam fir (Abies balsamea), tree
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red maple (Acer rubrum), tree
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black ash (Fraxinus nigra), tree
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yellow birch (Betula alleghaniensis), tree
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American fly honeysuckle (Lonicera canadensis), shrub
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swamp fly honeysuckle (Lonicera oblongifolia), shrub
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withe-rod (Viburnum nudum var. cassinoides), shrub
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mountain maple (Acer spicatum), shrub
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sedge (Carex), grass
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naked miterwort (Mitella nuda), other herbaceous
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bluntleaved orchid (Platanthera obtusata), other herbaceous
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sidebells wintergreen (Orthilia secunda), other herbaceous
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robin runaway (Dalibarda repens), other herbaceous
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bunchberry dogwood (Cornus canadensis), other herbaceous
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bluebead (Clintonia borealis), other herbaceous
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creeping snowberry (Gaultheria hispidula), other herbaceous
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threeleaf goldthread (Coptis trifolia), other herbaceous
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mountain woodsorrel (Oxalis montana), other herbaceous
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twinflower (Linnaea borealis), other herbaceous
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heartleaf foamflower (Tiarella cordifolia), other herbaceous
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western oakfern (Gymnocarpium dryopteris), other herbaceous
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splendid feather moss (Hylocomium splendens), other herbaceous
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delicate thuidium moss (Thuidium delicatulum), other herbaceous
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rough goose neck moss (Rhytidiadelphus triquetrus), other herbaceous
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(Bazzania trilobata), other herbaceous
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sphagnum (Sphagnum), other herbaceous
Community 1.2
Temporary Herbaceous / Open Seeps
These are open canopy gaps, which can either be a transitional phase or persistent phase depending on subsurface groundwater flow. These will consist primarily of diverse grasses and forbs, with sparse to absent trees and shrubs due high soil saturation and shallow root restrictions. These may be narrow to open patches, with occasional trees being present but will typically tip up at young ages due to the unstable grounds if present as a persistent seep. If a transitional temporary herbaceous phase, seedlings may be present in small amounts. Bryophytes are often abundant in these areas.
Dominant plant species
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eastern rough sedge (Carex scabrata), grass
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melic mannagrass (Glyceria melicaria), grass
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golden saxifrage (Chrysosplenium), other herbaceous
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eastern swamp saxifrage (Saxifraga pensylvanica), other herbaceous
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American marshpennywort (Hydrocotyle americana), other herbaceous
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jewelweed (Impatiens capensis), other herbaceous
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sensitive fern (Onoclea sensibilis), other herbaceous
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false hellebore (Veratrum nigrum), other herbaceous
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drooping woodreed (Cinna latifolia), other herbaceous
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brachythecium moss (Brachythecium rivulare), other herbaceous
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undulate atrichum moss (Atrichum undulatum), other herbaceous
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rhizomnium moss (Rhizomnium punctatum), other herbaceous
Community 1.3
Early Seral Forest
Seedling and sapling regeneration of cedar and balsam fir is abundant and may be intermixed with other hardwood species such as gray and yellow birch, red maple, and black ash. Faster growing trees such as balsam fir may temporarily outcompete other species, especially cedar, which is considered a slow growing tree. 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.
Community 1.4
Mixed Cedar – Hardwood Mid-Succession Forest
This successional phase consists of a mixed canopy of northern white cedar trees 50 to 100 years old or older and mature early to mid-successional species such as yellow birch, grey birch, paper birch, balsam fir, 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 cedar forest.
In community variants where this occurs on more sloped areas, yellow birch can persist as a canopy dominant and be mixed with the cedar canopy. Groundwater seeps can be seen or head moving just below the soil surface. Herbaceous plants more common in upland habitats may be common and bryophyte cover may be low.
Pathway 1.1A
Community 1.1 to 1.2
This may occur in areas where subsurface water flow is increased due to changes in hydrologic input or upslope soil damage. Increased seepage may weaken rooting stability and support graminoid and forbs rather than mature trees. Natural blowdowns from windstorms, ice or snow damage may also reflect a similar transition, opening the canopy and allowing for the temporary dominance of grasses and forbs. Harvesting methods such as patch cuts or clearcuts for pulpwood and lumber may also result in this community’s temporary dominance by increasing soil wetness and light availability. 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 northern white cedar 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 cedar forests since there has often been difficulty in regenerating cedar stands due to heavy browse by deer. This may have 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 50 years post canopy disturbance. Planting of northern white cedar can help accelerate the restoration of the natural vegetation of the swamp.
Pathway 1.3A
Community 1.3 to 1.2
This may occur in areas where subsurface water flow is increased due to changes in hydrologic input or upslope soil damage. Increased seepage may weaken rooting stability and support graminoid and forbs rather than mature trees. Natural blowdowns from windstorms, ice or snow damage may also reflect a similar transition, opening the canopy and allowing for the temporary dominance of grasses and forbs. Harvesting methods such as patch cuts or clearcuts for pulpwood may also result in this community’s temporary dominance by increasing soil wetness and light availability. 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 50 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 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 cedar stand to mature is 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. Northern white cedar 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 in areas where subsurface water flow is increased due to changes in hydrologic input or upslope soil damage. Increased seepage may weaken rooting stability and support graminoid and forbs rather than mature trees. Natural blowdowns from windstorms, ice or snow damage may also reflect a similar transition, opening the canopy and allowing for the temporary dominance of grasses and forbs. Harvesting methods such as patch cuts or clearcuts for pulpwood and lumber may also result in this community’s temporary dominance by increasing soil wetness and light availability. 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 1.4C
Community 1.4 to 1.3
This transition can occur through shelterwood strip cuts, in which the mature northern white cedar 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 cedar forests since there has often been difficulty in regenerating cedar stands due to heavy browse by deer.
State 2
Hardwood Seepage Swamps
These are hardwood dominated seepage swamps most often comprised of red maple (Acer rubrum), black, white, or green ash (Fraxinus nigra, F. americana, F. pennsylvania, respectfully), and yellow birch (Betula alleghenies) are found on shallow to absent organic soil over dense till. The canopy will be mostly hardwoods with softwoods, often northern white cedar (Thuja occidentalis), hemlock (Tsuga canadensis), or red spruce (Picea rubra); present but making up less than 25 percent of the canopy. The canopy will often be closed (greater than 60 percent canopy cover) with both the tall and shrub layer being generally sparse. Sapling regeneration can be common. The herbaceous layer is generally complex due to the variable canopy but consists of forbs and primarily herbaceous litter.
Community 2.1
Mid Successional Seepage Hardwood Forest
Ash and / or yellow birch are dominant in the canopy, with red maple present but not always dominant. Softwoods such as northern white cedar, hemlock, red spruce, white pine, and balsam fir may be present but make up less than 25 percent of the total canopy. The canopy will often be closed (35 to 85 percent cover of each species) and will often create a dark, cool forest floor during the summer months. A patchy shrub layer is often present with a highly diverse herbaceous layer reflecting both upland and wetland species. The groundcover will typically consist of herbaceous litter. Bryoids are sparse to abundant and will be locally dependent on subsurface seepage and cover by herbaceous litter.
Within the Northeast US, this community type correlates to Maine’s “Hardwood Seepage Forest” and “Black Ash Swamp” concept (Gawler and Cutko 2010), New Hampshire’s “Northern Hardwood – Black Ash – Conifer Swamp” concept (Sperduto and Nichols 2012), and New York’s “Red Maple – Hardwood Swamp” concept (Edinger et al. 2014). This correlates with NatureServes ‘Betula alleghaniensis - Acer rubrum - (Tsuga canadensis, Abies balsamea) / Osmunda cinnamomea Swamp Forest' Association (CEGL006380).
Dominant plant species
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black ash (Fraxinus nigra), tree
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white ash (Fraxinus americana), tree
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green ash (Fraxinus pennsylvanica), tree
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yellow birch (Betula alleghaniensis), tree
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red maple (Acer rubrum), tree
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arborvitae (Thuja occidentalis), tree
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balsam fir (Abies balsamea), tree
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red spruce (Picea rubens), tree
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upright sedge (Carex stricta), grass
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prickly bog sedge (Carex atlantica), grass
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silvery sedge (Carex canescens), grass
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longhair sedge (Carex comosa), grass
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broom sedge (Carex scoparia), grass
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fox sedge (Carex vulpinoidea), grass
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rattlesnake mannagrass (Glyceria canadensis), grass
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common rush (Juncus effusus), grass
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rice cutgrass (Leersia oryzoides), grass
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woolgrass (Scirpus cyperinus), grass
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sensitive fern (Onoclea sensibilis), other herbaceous
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royal fern (Osmunda regalis), other herbaceous
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eastern marsh fern (Thelypteris palustris), other herbaceous
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jewelweed (Impatiens capensis), other herbaceous
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purple avens (Geum rivale), other herbaceous
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Schweinitz's ragwort (Packera schweinitziana), other herbaceous
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heartleaf foamflower (Tiarella cordifolia), other herbaceous
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small enchanter's nightshade (Circaea alpina), other herbaceous
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white turtlehead (Chelone glabra), other herbaceous
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splendid feather moss (Hylocomium splendens), other herbaceous
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delicate thuidium moss (Thuidium delicatulum), other herbaceous
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(Bazzania trilobata), other herbaceous
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sphagnum (Sphagnum), other herbaceous
State 3
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 root restrictive layer and shallow organic soils compared to other sites which may have deeper organic soils. Standing dead snags may or may not be present depending on time since hydrological change.
Community 3.1
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
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upright sedge (Carex stricta), grass
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blister sedge (Carex vesicaria), grass
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Northwest Territory sedge (Carex utriculata), grass
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bluejoint (Calamagrostis canadensis), grass
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rattlesnake mannagrass (Glyceria canadensis), grass
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three-way sedge (Dulichium arundinaceum), grass
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common rush (Juncus effusus), grass
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rice cutgrass (Leersia oryzoides), grass
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woolgrass (Scirpus cyperinus), grass
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swamp milkweed (Asclepias incarnata), other herbaceous
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eastern marsh fern (Thelypteris palustris), other herbaceous
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spotted joe pye weed (Eutrochium maculatum), other herbaceous
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marsh bellflower (Campanula aparinoides), other herbaceous
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royal fern (Osmunda regalis), other herbaceous
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purple marshlocks (Comarum palustre), other herbaceous
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thoroughwort (Eupatorium), other herbaceous
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Magellan's sphagnum (Sphagnum magellanicum), other herbaceous
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Girgensohn's sphagnum (Sphagnum girgensohnii), other herbaceous
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prairie sphagnum (Sphagnum palustre), other herbaceous
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drepanocladus moss (Drepanocladus aduncus), other herbaceous
Community 3.2
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
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arborvitae (Thuja occidentalis), tree
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red maple (Acer rubrum), tree
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black ash (Fraxinus nigra), tree
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gray alder (Alnus incana), shrub
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hazel alder (Alnus serrulata), shrub
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redosier dogwood (Cornus sericea), shrub
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American red raspberry (Rubus idaeus), shrub
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steeplebush (Spiraea tomentosa), shrub
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willow (Salix), shrub
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viburnum (Viburnum), shrub
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parasol whitetop (Doellingeria umbellata), other herbaceous
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spotted joe pye weed (Eutrochium maculatum), other herbaceous
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jewelweed (Impatiens capensis), other herbaceous
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northern bugleweed (Lycopus uniflorus), other herbaceous
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sensitive fern (Onoclea sensibilis), other herbaceous
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cinnamon fern (Osmunda cinnamomea), other herbaceous
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eastern marsh fern (Thelypteris palustris), other herbaceous
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violet (Viola), other herbaceous
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sphagnum (Sphagnum), other herbaceous
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tree climacium moss (Climacium dendroides), other herbaceous
Pathway 3.1A
Community 3.1 to 3.2
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 4
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.
Community 4.1
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
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timothy (Phleum pratense), grass
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sweet vernalgrass (Anthoxanthum odoratum), grass
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Kentucky bluegrass (Poa pratensis), grass
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orchardgrass (Dactylis glomerata), grass
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smooth brome (Bromus inermis), grass
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red fescue (Festuca rubra), grass
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sheep fescue (Festuca ovina), grass
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perennial ryegrass (Lolium perenne), grass
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redtop (Agrostis gigantea), grass
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festulolium (×Festulolium), grass
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alfalfa (Medicago sativa), other herbaceous
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red clover (Trifolium pratense), other herbaceous
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milkvetch (Astragalus), other herbaceous
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bedstraw (Galium), other herbaceous
Community 4.2
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.
Pathway 4.1A
Community 4.1 to 4.2
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 4.2A
Community 4.2 to 4.1
This transition may occur through management practices via mechanical, chemical, or biological means may be used to remove undesirable pasture or hayland species.
State 5
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
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cattail (Typha), other herbaceous
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pickerelweed (Pontederia), other herbaceous
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arrowhead (Sagittaria), other herbaceous
Community 5.1
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.
Community 5.2
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 5.1A
Community 5.1 to 5.2
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 5.2A
Community 5.2 to 5.1
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 extensive selective harvesting of cedar, in which the seedbank supply is exhausted, and the conditions are unfit for regeneration. This may also occur through extensive winter browse by deer on regenerating cedar in early successional forests due to its high forage value. In any case, hardwood species will persist and outcompete northern white cedar, transitioning a community from evergreen to hardwood dominance.
Transition T1B
State 1 to 3
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 T1C
State 1 to 4
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 selective harvesting of hardwood species and forest management to promote cedar regeneration. This may require planting of seedlings if the seedbank is exhausted and active management to ensure seedling survival. If hydrologic changes were the dominant transitional driver, restoration to the natural hydrology of the site may be needed.
Transition T2B
State 2 to 3
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 T3A
State 3 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 T3B
State 3 to 5
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 T4A
State 4 to 1
This transition may occur following long-term agricultural abandonment. Northern white cedar, white pine, gray birch, aspen, red spruce, pin cherry, and balsam fir may be post-agricultural successional species that will invade a fallow pastureland depending on the available seedbank and the duration and intensity of the disturbance.
Transition T5A
State 5 to 3
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.
