Rich Hemlock-Hardwood Peat Swamp

Rich hemlock-hardwood peat swamp

Forested Peatlands
State Protection
Not Listed
Not listed or protected by New York State.
Federal Protection
Not Listed
State Conservation Status Rank
Imperiled or Vulnerable in New York - Very vulnerable, or vulnerable, to disappearing from New York, due to rarity or other factors; typically 6 to 80 populations or locations in New York, few individuals, restricted range, few remaining acres (or miles of stream), and/or recent and widespread declines. More information is needed to assign either S2 or S3.
Global Conservation Status Rank
Vulnerable globally, or Apparently Secure - At moderate risk of extinction, with relatively few populations or locations in the world, few individuals, and/or restricted range; or uncommon but not rare globally; may be rare in some parts of its range; possibly some cause for long-term concern due to declines or other factors. More information is needed to assign either G3 or G4.


Did you know?

The wooly adelgid (Adelges tsugae), a non-native aphid-like insect, has become a serious threat to eastern hemlock. These insects feed on the sap of the youngest branches of hemlock where the needles attach to the twig. The adelgids inject a toxic saliva into the plant as they feed, killing existing needles and interfering with the tree's ability to produce new ones. If it is not controlled, the infected trees may die in three to four years.

State Ranking Justification

There are several hundred occurrences statewide. Some documented occurrences have good viability and many are protected on public land or private conservation land. This community is sparsely scattered but probably widespread throughout upstate New York, and includes several large, high quality examples. The current trend of this community is probably stable for occurrences on public land, or declining slightly elsewhere due to moderate threats that include alteration of the natural hydrology (primarily by beaver) and invasive species.

Short-term Trends

The number and acreage of rich hemlock-hardwood peat swamps in New York have probably declined slightly, or have remained stable, in recent decades as a result of wetland protection regulations. A few examples may have declined due to flooding by beaver.

Long-term Trends

The number and acreage of rich hemlock-hardwood peat swamps in New York have probably declined substantially from historical numbers likely correlated with agricultural and development.

Conservation and Management


Rich hemlock-hardwood peat swamps are threatened by development (e.g., agriculture, residential), habitat alteration (e.g., excessive logging, sediment and pollution run-off), and recreational overuse (e.g., hiking trails, horse trails, ATVs, campgrounds). Alteration to the natural hydrological regime is also a threat to this community (e.g., impoundments, blocked culverts, beaver). A few swamps are threatened by over-browsing by deer. Several rich hemlock-hardwood peat swamps are threatened by invasive species, such as purple loosestrife (Lythrum salicaria). Hemlock woolly adelgid (Adelges tsugae) is an exotic species that could potentially have a devastating effect on hemlock trees in New York. This exotic "sap-sucker" has only recently begun to spread through the forests of the northeastern United States. Without control measures, insect-infected trees will probably die within three to four years (McClure et al. 2001, Bishop 2002, Ward et al. 2004). Although current adelgid infestations are primarily confined to southeastern New York, in 2002 adelgid infestation was newly observed in Monroe County (USDA Forest Service 2002).

Conservation Strategies and Management Practices

Where practical, establish and maintain a natural wetland buffer to reduce storm-water, pollution, and nutrient run-off, while simultaneously capturing sediments before they reach the wetland. Buffer width should take into account the erodibility of the surrounding soils, slope steepness, and current land use. Wetlands protected under Article 24 are known as New York State "regulated" wetlands. The regulated area includes the wetlands themselves, as well as a protective buffer or "adjacent area" extending 100 feet landward of the wetland boundary (NYS DEC 1995). If possible, minimize the number and size of impervious surfaces in the surrounding landscape. Avoid habitat alteration within the wetland and surrounding landscape. For example, roads and trails should be routed around wetlands, and ideally not pass through the buffer area. If the wetland must be crossed, then bridges and boardwalks are preferred over filling. Restore swamps that have been affected by unnatural disturbance (e.g., remove obsolete impoundments and ditches in order to restore the natural hydrology). Prevent the spread of invasive exotic species into the wetland through appropriate direct management, and by minimizing potential dispersal corridors, such as roads.

Development and Mitigation Considerations

When considering road construction and other development activities, minimize actions that will change what water carries and how water travels to this community, both on the surface and underground. Water traveling over-the-ground as run-off usually carries an abundance of silt, clay, and other particulates during (and often after) a construction project. While still suspended in the water, these particulates make it difficult for aquatic animals to find food; after settling to the bottom of the wetland, these particulates bury small plants and animals and alter the natural functions of the community in many other ways. Thus, road construction and development activities near this community type should strive to minimize particulate-laden run-off into this community. Water traveling on the ground or seeping through the ground also carries dissolved minerals and chemicals. Road salt, for example, is becoming an increasing problem both to natural communities and as a contaminant in household wells. Fertilizers, detergents, and other chemicals that increase the nutrient levels in wetlands cause algae blooms and eventually an oxygen-depleted environment where few animals can live. Herbicides and pesticides often travel far from where they are applied and have lasting effects on the quality of the natural community. So, road construction and other development activities should strive to consider: 1. how water moves through the ground, 2. the types of dissolved substances these development activities may release, and 3. how to minimize the potential for these dissolved substances to reach this natural community.

Inventory Needs

Survey for occurrences statewide to advance documentation and classification of rich hemlock-hardwood peat swamps. Continue searching for large sites in good condition especially those over 100 acres.

Research Needs

Research composition of rich hemlock-hardwood peat swamps statewide in order to characterize variations. Collect sufficient plot data to support the recognition of several distinct rich hemlock-hardwood peat swamp types based on composition and by ecoregion.

Rare Species

  • Carex buxbaumii (Brown Bog Sedge) (guide)
  • Carex schweinitzii (Schweinitz's Sedge) (guide)
  • Carex vaginata (Sheathed Sedge) (guide)
  • Cirriphyllum piliferum (Hair-pointed Moss) (guide)
  • Corallorhiza striata var. striata (Striped Coralroot) (guide)
  • Cypripedium candidum (Small White Lady's Slipper) (guide)
  • Neottia convallarioides (Broad-lipped Twayblade) (guide)
  • Poa paludigena (Slender Marsh Blue Grass) (guide)
  • Pyrola asarifolia ssp. asarifolia (Pink Shinleaf) (guide)
  • Symphyotrichum boreale (Northern Bog Aster) (guide)
  • Trollius laxus (Spreading Globeflower) (guide)


New York State Distribution

This community is sparsely scattered but is probably widespread throughout upstate New York north of the Hudson Highlands. It may be concentrated in the Great Lakes and High Allegheny Plateau Ecoregions, especially the Finger Lakes Highlands and suspected to extend northeast in this part of the state only to about Oneida County. It is essentially absent from the Northern Appalachians Ecoregion and the northeastern part of the state except for disjunct occurrences known from the Lake Champlain Valley of the Great Lakes Ecoregion at Brayton Marsh in Warren County and Wickham Marsh in Essex County. It is suspected to be lacking or very uncommon in the Lower New England Ecoregion.

Global Distribution

This community is concentrated in the Great Lakes basin and High Allegheny Plateau. This range is estimated to span north to southern Ontario, west to Wisconsin, southwest to Tennessee, southeast to North Carolina, and north possibly to Vermont.

Best Places to See

  • Tompkins State Forest (Tompkins County)
  • Buttermilk Falls State Park (Tompkins County)
  • Cayuga State Forest
  • Adirondack Park (Warren County)

Identification Comments

General Description

A mixed conifer-hardwood swamp that occurs on peat, and that receives calcareous groundwater discharge. These swamps usually have a fairly open canopy (50 to 70% cover), scattered shrubs, and a diverse ground layer of sedges, mosses, ferns, and forbs. Characteristic canopy trees include eastern hemlock (Tsuga canadensis), which usually has at least 20% cover, and various hardwood and conifer associates. Characteristic understory species include sedges (Carex spp.), ferns, and a number species intolerant to acidic conditions, such as skunk cabbage (Symplocarpus foetidus) and alder-leaved buckthorn (Rhamnus alnifolia).

Characters Most Useful for Identification

A diverse, somewhat open canopy (usually between 50 to 70% cover) hemlock-dominated peatland swamp. Typically a diversity of microhabitats are present, which frequently include seeps and herbaceous-dominated canopy gaps.

Elevation Range

Known examples of this community have been found at elevations between 328 feet and 1,650 feet.

Best Time to See

Rich hemlock-hardwood peat swamps support lush vegetation throughout much of the growing season.

Rich Hemlock-Hardwood Peat Swamp Images


International Vegetation Classification Associations

This New York natural community encompasses all or part of the concept of the following International Vegetation Classification (IVC) natural community associations. These are often described at finer resolution than New York's natural communities. The IVC is developed and maintained by NatureServe.

  • Red Maple - Black Ash - (Eastern Hemlock) / Heartleaf Foamflower Swamp Forest (CEGL006502)

NatureServe Ecological Systems

This New York natural community falls into the following ecological system(s). Ecological systems are often described at a coarser resolution than New York's natural communities and tend to represent clusters of associations found in similar environments. The ecological systems project is developed and maintained by NatureServe.

  • Laurentian-Acadian Acidic Cliff and Talus (CES201.569)

Characteristic Species

  • Trees > 5m

    • Acer rubrum var. rubrum (common red maple)
    • Betula alleghaniensis (yellow birch)
    • Fraxinus nigra (black ash)
    • Larix laricina (tamarack)
    • Pinus strobus (white pine)
    • Tsuga canadensis (eastern hemlock)
  • Shrubs 2 - 5m

    • Alnus incana ssp. rugosa (speckled alder)
    • Carpinus caroliniana ssp. virginiana (musclewood, ironwood, American hornbeam)
    • Hamamelis virginiana (witch-hazel)
    • Ilex verticillata (common winterberry)
    • Rhamnus alnifolia (alder-leaved buckthorn)
    • Vaccinium corymbosum (highbush blueberry)
  • Shrubs < 2m

    • Lindera benzoin (spicebush)
    • Ribes spp.
    • Rubus pubescens (dwarf raspberry)
  • Vines

    • Parthenocissus quinquefolia (Virginia-creeper)
    • Toxicodendron radicans ssp. radicans (eastern poison-ivy)
  • Herbs

    • Caltha palustris (marsh-marigold)
    • Carex spp.
    • Coptis trifolia (gold-thread)
    • Dryopteris intermedia (evergreen wood fern, fancy wood fern, common wood fern)
    • Glyceria striata (fowl manna grass)
    • Impatiens capensis (spotted jewelweed, spotted touch-me-not)
    • Maianthemum canadense (Canada mayflower)
    • Maianthemum stellatum (starry Solomon's-seal)
    • Micranthes pensylvanica (swamp-saxifrage)
    • Onoclea sensibilis (sensitive fern)
    • Osmunda regalis var. spectabilis (royal fern)
    • Osmundastrum cinnamomeum var. cinnamomeum (cinnamon fern)
    • Packera aurea (golden ragwort)
    • Symplocarpus foetidus (skunk-cabbage)
    • Thalictrum pubescens (tall meadow-rue)
    • Tiarella cordifolia (foamflower)
    • Trollius laxus (spreading globeflower)
  • Nonvascular plants

    • Campylium sp.
    • Sphagnum spp.
    • Thuidium delicatulum

Similar Ecological Communities

  • Hemlock-hardwood swamp (guide)
    Rich hemlock-hardwood peat swamps have more open canopies (50-70% cover) than hemlock-hardwood swamps, and have a more diverse herbaceous ground layer. Hemlock-hardwood swamps have over 70% canopy cover, mineral or muck soils, and low species diversity.
  • Northern white cedar swamp (guide)
    Northern white cedar swamps have canopies with at least 30% cover of northern white cedar (Thuja occidentalis). Combined cover of northern white cedar and black ash (Fraxinus nigra) is greater than that of hemlock and white pine; otherwise this community grades into rich hemlock-hardwood peat swamp.
  • Red maple-tamarack peat swamp (guide)
    Red maple-tamarack peat swamps are dominated by tamarack (Larix laricina) and red maple (Acer rubrum) with hemlock lacking, or present only as a minor associate. Sites where hemlock is more abundant than tamarack grade into hemlock-hardwood, or rich hemlock-hardwood peat swamp, depending on the soil type and herb layer diversity present.


Trees > 5m
Shrubs 2 - 5m
Shrubs < 2m
Nonvascular plants

Percent cover

This figure helps visualize the structure and "look" or "feel" of a typical Rich Hemlock-Hardwood Peat Swamp. Each bar represents the amount of "coverage" for all the species growing at that height. Because layers overlap (shrubs may grow under trees, for example), the shaded regions can add up to more than 100%.

Additional Resources


Cowardin, L.M., V. Carter, F.C. Golet, and E.T. La Roe. 1979. Classification of wetlands and deepwater habitats of the United States. U.S. Fish and Wildlife Service. Washington, D.C. 131 pp.

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.

Edinger, Gregory J., D.J. Evans, Shane Gebauer, Timothy G. Howard, David M. Hunt, and Adele M. Olivero (editors). 2002. Ecological Communities of New York State. Second Edition. A revised and expanded edition of Carol Reschke's Ecological Communities of New York State. (Draft for review). New York Natural Heritage Program, New York State Department of Environmental Conservation. Albany, NY. 136 pp.

McClure, M.S., S.M. Salom, and K.S. Sheilds. 2001. Hemlock wooly adelgid. United States Department of Agriculture, Forest Service, Forest Health Technology Enterprise Team. Connecticut Agricultural Experiment Station, Windsor, CT.

New York Natural Heritage Program. 2024. New York Natural Heritage Program Databases. Albany, NY.

New York State Department of Environmental Conservation. 1995. Freshwater Wetlands: Delineation Manual. July 1995. New York State Department of Environmental Conservation. Division of Fish, Wildlife, and Marine Resources. Bureau of Habitat. Albany, NY.

Reschke, Carol. 1990. Ecological communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation. Latham, NY. 96 pp. plus xi.


About This Guide

This guide was authored by: Aissa Feldmann

Information for this guide was last updated on: May 16, 2024

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Rich hemlock-hardwood peat swamp. Available from: Accessed July 19, 2024.