Great Plains Mesic Forest and Woodland
Global Name:
Northern Great Plains Mesic Forest & Woodland
Global Rank:
G3?
State Rank:
S3
(see reason below)
External Links
State Rank Reason
This habitat is vulnerable from several threats though it is still relatively common in some areas and has a large range extent. The degree of threats and the amount of loss in condition, function and extent is somewhat poorly documented.
General Description
This National Vegetation Classification Group is typically associated with intermittent or ephemeral streams in the Great Plains and commonly dominated by American Elm (Ulmus americana) or Green Ash (Fraxinus pennsylvanica). These communities occur on northerly slopes or within the bottoms of draws and ravines where topography produces higher moisture levels than commonly found in the surrounding area. Tree canopy cover is variable, ranging from open to closed and trees are often short (<30ft tall). In some areas of the western Great Plains, Rocky Mountain Juniper (Juniperus scopulorum) may dominate the canopy. Quaking Aspen (Populus tremuloides), Paper Birch (Betula papyrifera), or Boxelder (Acer negundo) are commonly present in portions of the northwestern Great Plains. In central and eastern Montana, Green Ash (Fraxinus pennsylvanicus) or Chokecherry (Prunus virginiana) are the usual dominants. Hawthorns (Crataegus spp) are occasionally seen as dominant species in some areas. This group is often found in ravines formed by ephemeral and intermittent streams, and on toeslopes and north-facing slopes. Generally, these communities are less than 50 meters (165 feet) wide, although the linear extent may be considerable. Soils are usually deep and loamy. Stands of this group that occur on upper terraces and toeslopes in riparian areas are rarely flooded but have root access to groundwater.
This group encompasses a portion of the Great Plains Wooded Draw and Ravine Ecological System.
Diagnostic Characteristics
Deciduous Forest and Woodland; Great Plains Region; Upper River Terraces, Protected Slopes (often north-facing), Ravines, and Draws.
Typical Dominants: American Elm (Ulmus americana), Green Ash (Fraxinus pennsylvanica)
Similar Systems
Range
This group occurs across the Great Plains in Montana, especially in the eastern portion where American Elm is present. It may be found within the Milk, Missouri and Yellowstone River drainages.
In Montana, G145 occurs in Level III Ecoregions 42 (Northwestern Glaciated Plains) and 43 (Northwestern Great Plains).
In Montana, G145 occurs within these Major Land Resource Areas: 52 - Brown Glaciated Plains, 53A - Northern Dark Brown Glaciated Plains, 53B - Central Dark Brown Glaciated Plains, 58 - Northern Rolling High Plains, and potentially in 60A - Pierre Shale Plains and 60B - Pierre Shale Plains, Northern Part
Density and Distribution
Based on 2025 land cover layer. Grid on map is based on USGS 7.5 minute quadrangle map boundaries.
Mapped Distribution by County
Big Horn, Blaine, Carbon, Carter, Cascade, Chouteau, Custer, Daniels, Dawson, Fallon, Fergus, Garfield, Glacier, Golden Valley, Hill, Judith Basin, Lewis and Clark, Liberty, Mccone, Meagher, Musselshell, Park, Petroleum, Phillips, Pondera, Powder River, Prairie, Richland, Roosevelt, Rosebud, Sheridan, Stillwater, Sweet Grass, Teton, Toole, Treasure, Valley, Wheatland, Wibaux, Yellowstone
Based on 2025 land cover layer.
Spatial Pattern
Small Patch
Environment
This group is typically associated with intermittent or ephemeral streams within the bottoms of draws and ravines or on northerly slopes where topography produces higher moisture levels than are commonly found throughout the surrounding area. Communities are best developed under conditions that favor snow entrapment, development of deeper soils, and concentration of moisture. These conditions are typical of ravines formed by ephemeral and intermittent streams and on toeslopes and north-facing slopes. Generally, these systems are less than 50 meters (165 feet) wide, although the linear extent may be considerable. Soils are usually deep loams. Stands of this group that occur on upper terraces and toeslopes in riparian areas are rarely flooded but have root access to groundwater. Flooding is very short in duration when it occurs, as water is rapidly channeled downslope. Similar communities that occur on well-developed floodplains that are more regularly flooded are part of G147 Great Plains Floodplain Forest. Adjacent uplands are generally Great Plains mixed grass prairies and shrublands.
Vegetation
This group is commonly dominated by American Elm (Ulmus americana) or Green Ash (Fraxinus pennsylvanica). In some areas, Rocky Mountain Juniper (Juniperus scopulorum) may dominate or co-dominate the canopy. Quaking Aspen (Populus tremuloides), Paper Birch (Betula papyrifera), and Boxelder (Acer negundo) are common associates. Hawthorns (Crataegus spp) are occasionally seen as dominants in some areas. Tree canopy cover is variable, ranging from open to closed and trees are often short (<30ft tall) in stature.
Chokecherry (Prunus virginiana) and western Snowberry (Symphoricarpos occidentalis) are common shrubs components. In many parts of eastern Montana, particularly in disturbed settings, the understory is a dense shrub layer of Western Snowberry. In less disturbed sites, the understory is two-layered, with a shrub layer of Chokecherry and other Prunus species, as well as Hawthorne, Silverberry (Elaeagnus commutata), Currant and Gooseberry (Ribes spp), Woods' Rose (Rosa woodsii), and Silver Buffaloberry (Shepherdia argentea). The lowest layer is dominated by Sedges (Carex species) and grasses such as Western Wheatgrass (Elymus smithii), Bluebunch Wheatgrass (Elymus spicatus), and Thickspike Wheatgrass (Elymus lanceolatus). Common forbs include American Licorice (Glycyrrhiza lepidota), Yarrow (Achillea millefolium), Purple Meadowrue (Thalictrum dasycarpum), Starry False Solomon's-seal (Smilacina stellata) and Bedstraw (Galium spp). Exotics such as Russian olive (Elaeagnus angustifolia), Yellow Sweetclover (Meliotus officinalis), Kentucky Bluegrass (Poa pratensis), Smooth Brome (Bromus inermis) and Leafy Spurge (Euphorbia virgata) are often present, especially near agricultural settings.
Alliances and Associations in this group within the National Vegetation Classification are poorly documented with only one alliance and one association currently described or attributed to Montana.
National Vegetation Classification
Download the complete NVC hierarchy for Montana
TT2 B02 Temperate-Boreal Forest and Woodland
TT2.b S92 Cool Temperate Forest and Woodland
TT2.b1 F107 Temperate Deciduous-Mixed Forest and Woodland
TT2.b1.Nb D332 North American Great Plains Forest and Woodland
TT2.b1.Nb.2 M545 Northern Great Plains Forest and Woodland
TT2.b1.Nb.2.a G145 Northern Great Plains Mesic Forest and Woodland
A3211 Fraxinus pennsylvanica - Ulmus americana Great Plains Forest Alliance
CEGL000643 Fraxinus pennsylvanica - Ulmus americana / Prunus virginiana Woodland
*Disclaimer: Some Alliances and Associations are considered provisional. Some require further documentation to verify their occurrence in the state
and some may be modified or deleted in future revisions after collection of additional data and information.
Dynamic Processes
Livestock use and invasion by non-native species are major disturbances in this group. Both domestic animals and wildlife use this group readily, leading to trampling of vegetation and an increase in shrub and grass domination. Boxelder is highly susceptible to mechanical damage from livestock (Rosario 1988), and in stands where green ash is dominant, heavy livestock grazing may prevent regeneration, leading to more open stands dominated by exotic perennial grasses (Lesica 2009). A study in Green Ash dominated draws in the northern Great Plains found that exclusion of livestock increased tree height and decreased mortality for both Green Ash and Elm (Uresk et al. 2009).
Fire is an important process and may promote regeneration by encouraging sprouting and thinning of stands (Lesica 2003). Fire return intervals in these communities average approximately 30 years and range from low-severity surface fires to stand-replacing burns (U.S. Department of Agriculture 2012). Most community dominants are highly susceptible to fire, although Green Ash and Rocky Mountain Juniper may survive low-intensity burns in some cases (Gucker 2005; Scher 2002). Despite experiencing high mortality due to fire, species in this group are fire-adapted and recover quickly via root sprouting, as is the case with Aspen and Green Ash, or by prolific seed production and wind dispersal, as is the case with Paper Birch and Boxelder. Most species in this group, however, are capable of utilizing both strategies to varying degrees (Gucker 2005; Howard 1996; Uchytil 1991; Rosario 1988).
In parts of eastern Montana, non-native species like Russian Olive have invaded these communities altering vegetation composition and changing biogeochemical cycling in streams (Mineau et al. 2011). Russian Olive trees are fast-growing and form a dense canopy that prevents the more shade-intolerant native species typical of this group from establishing (Combs 2010). Additionally, Russian Olive exerts a strong competitive effect on native tree, inhibiting their establishment (Katz and Shafroth 2003). Non-native grasses also alter species composition within these communities, particularly where green ash is dominant, by forming dense sods and preventing seedling recruitment (Lesica 2009).
Management
Shade and moisture draw livestock into draws and ravines, concentrating use and creating the potential for degradation and the spread of exotic and invasive species. Alternative areas of shade, water, and forage for livestock can reduce pressure on these communities and maintain them as wildlife habitat. Fire may have mixed effects on this group. In southeastern Montana, burning resulted in increased abundance and size of crown sprouts in Green Ash-dominated wooded draws, although significantly fewer seedlings were observed in burned sites (Lesica 2003). Prescribed burning may be beneficial for maintaining this group where regrowth will not be impeded by invasive grasses, intensive ungulate browsing, or where Russian Olive has not invaded (Lesica and Marlow 2011; Lesica 2009; Katz and Shafroth 2003).
Restoration Considerations
Restoration of this group may in part require alternate grazing practices to allow for successful recovery. Dominant species such as Chokecherry, Hawthorne and Elm have extensive root systems and are rated as good to excellent for soil erosion control. Aspen and Paper Birch are additionally recommended for revegetation and soil stabilization (Howard 1996; Uchytil 1991). In some cases, shrubs can be planted in clusters or bands in areas with high soil erosion potential. All other associated understory shrubs within this group - Western Snowberry, Silverberry, Currants and Gooseberry, Woods' Rose, and Silver Buffaloberry - are rated as good to excellent restoration species, and possess strongly rhizomatous root systems that minimize soil erosion on steep slopes.
In order to promote regeneration in areas where green ash recruitment has been prevented by exotic grasses, Lesica (2009) recommends herbicide treatment followed by seeding. Alternatively, cutting of mature individuals encourages sprouting, which may be more successful than direct seeding. However, intensive browsing by ungulates may limit the success of this approach (Lesica 2009). In wooded draws where Russian Olive has become dominant, the most effective method of restoration employs a combination of chemical and mechanical treatments. Prescribed burning is not recommended as Russian Olive readily resprouts post-fire (Katz and Shafroth 2003). Combs (2010) recommends specific methods for reducing Russian Olive where invasion into this group has occurred.
Species Associated with this Community
- How Lists Were Created and Suggested Uses and Limitations
Animal Species Associations
Please note that while all vertebrate species have been systematically associated with vegetation communities, only a handful of invertebrate species have been associated with vegetation communities and invertebrates lists for each vegetation community should be regarded as incomplete. Animal species associations with natural vegetation communities that they regularly breed or overwinter in or migrate through were made by:
- Using personal observations and reviewing literature that summarize the breeding, overwintering, or migratory habitat requirements of each species (Dobkin 1992, Hart et al. 1998, Hutto and Young 1999, Maxell 2000, Werner et al. 2004, Adams 2003, and Foresman 2012);
- Evaluating structural characteristics and distribution of each vegetation community relative to the species' range and habitat requirements;
- Examining the observation records for each species in the state-wide point observation database associated with each vegetation community;
- Calculating the percentage of observations associated with each vegetation community relative to the percent of Montana covered by each vegetation community to get a measure of "observations versus availability of habitat".
Species that breed in Montana were only evaluated for breeding habitat use. Species that only overwinter in Montana were only evaluated for overwintering habitat use. Species that only migrate through Montana were only evaluated for migratory habitat use. In general, species are listed as associated with a vegetation community if it contains structural characteristics known to be used by the species. However, species are not listed as associated with a vegetation community if we found no support in the literature for the species’ use of structural characteristics of the community even if point observations were associated with it. If you have any questions or comments on animal species associations with vegetation communities, please contact the Montana Natural Heritage Program's Senior Zoologist.
Plant Species Associations
Please note that while diagnostic, dominant, or codominant vascular plant species for a vegetation community have been systematically assigned to those communities and vascular plant Species of Concern were systematically evaluated for their associations with vegetation communities, the majority of Montana’s vascular plant species have not been evaluated for their associations with vegetation communities and no attempt has been made to associate non-vascular plants, fungi, or lichens with vegetation communities. Plant species associations with natural vegetation communities were made in a manner similar to that described above for animals, but with review of Lesica et al. (2022) and specimen collection data from the Consortium of Pacific Northwest Herbaria. If you have any questions or comments on plant species associations with vegetation communities, please contact the Montana Natural Heritage Program's Program Botanist.
Suggested Uses and Limitations
Species associations with vegetation communities should be used to generate potential lists of species that may occupy broader landscapes for the purposes of landscape-level planning. These potential lists of species should not be used in place of documented occurrences of species or predicted habitat suitability models (this information can be requested at: https://mtnhp.mt.gov/requests/), or systematic surveys for species and onsite evaluations of habitat by trained biologists. Users of this information should be aware that the land cover data used to generate species associations is based on satellite imagery from 2016 and was only intended to be used at broader landscape scales. Land cover mapping accuracy is particularly problematic when the vegetation communities occur as small patches or where the land cover types have been altered over the past decade. Thus, particular caution should be used when using the associations in assessments of smaller areas (e.g., evaluations of public land survey sections). Finally, although a species may be associated with a particular vegetation community within its known geographic range, portions of that vegetation community may occur outside of the species' known geographic range.
Literature Cited
- Adams, R.A. 2003. Bats of the Rocky Mountain West; natural history, ecology, and conservation. Boulder, CO: University Press of Colorado. 289 p.
- Consortium of Pacific Northwest Herbaria. https://www.pnwherbaria.org/ Last accessed May 30, 2025.
- Dobkin, D. S. 1992. Neotropical migrant land birds in the Northern Rockies and Great Plains. USDA Forest Service, Northern Region. Publication No. R1-93-34. Missoula, MT.
- Foresman, K.R. 2012. Mammals of Montana. Second edition. Mountain Press Publishing, Missoula, Montana. 429 pp.
- Hart, M.M., W.A. Williams, P.C. Thornton, K.P. McLaughlin, C.M. Tobalske, B.A. Maxell, D.P. Hendricks, C.R. Peterson, and R.L. Redmond. 1998. Montana atlas of terrestrial vertebrates. Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT. 1302 p.
- Hutto, R.L. and J.S. Young. 1999. Habitat relationships of landbirds in the Northern Region, USDA Forest Service, Rocky Mountain Research Station RMRS-GTR-32. 72 p.
- Lesica P., M. Lavin, and P.F. Stickney. 2022. Manual of vascular plants, 2nd Edition. Brit Press. 779 p.
- Maxell, B.A. 2000. Management of Montana's amphibians: a review of factors that may present a risk to population viability and accounts on the identification, distribution, taxonomy, habitat use, natural history, and the status and conservation of individual species. Report to U.S. Forest Service Region 1. Missoula, MT: Wildlife Biology Program, University of Montana. 161 p.
- Werner, J.K., B.A. Maxell, P. Hendricks, and D. Flath. 2004. Amphibians and reptiles of Montana. Missoula, MT: Mountain Press Publishing Company. 262 p.
- Species of Concern Associated with this Community
Vascular Plants
Mammals
Birds
Reptiles
Amphibians
Invertebrates
- Diagnostic, Dominant, or Codominant Plant Species for this Community
Vascular Plants
- Other Native Species Commonly Associated with this Community
Vascular Plants
Original Concept Authors
J. Drake 2015
Montana Version Authors
S. Mincemoyer, L. Vance, T. Luna
Version Date
11/25/2024
References
- Literature Cited AboveLegend:
View Online Publication
Combs, J. 2010. Best Management Practices for Montana Biology, Ecology, and Management of Russian Olive (Elaeagnus angustifolia L.) and Saltcedar (Tamarix ramosissima, T. chinensis, and their hybrids). Natural Resource Conservation Service. ftp://ftpfc.sc.egov.usda.gov/MT/www/technical/invasive/Invasive_Species_Tech_Note_MT30.pdf.- Gucker, C.L. 2005. Fraxinus pennsylvanica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
- Howard, J.L. 1996. Populus tremuloides. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
- Katz, G.L. and P.B. Shafroth. 2003. Biology, ecology and management of Elaeagnus angustifolia L.(Russian olive) in western North America. Wetlands 23(4):763-777.
- Lesica, P. 2009. Can Regeneration of Green Ash (Fraxinus pennsylvanica) be Restored in Declining Woodlands in Eastern Montana?. Rangeland ecology & management 62(6):564-571.
- Lesica, P. and C.B. Marlow. 2011. Values and management of Montana’s green ash draws. MontGuide No. MT201114AG. Montana State University Extension.
- Lesica, Peter. 2003. 'Effects of Wildfire on Recruitment of Fraxinus pennsylvanica in Eastern Montana Woodlands'. American Midland Naturalist. 149 (2): 258-267.
- Mineau, M.M., C.V. Baxter, and A.M. Marcarelli. 2011. A non-native riparian tree (Elaeagnus angustifolia) changes nutrient dynamics in streams. Ecosystems 14(3):353-365.
- Rosario, L.C. 1988. Acer negundo. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
- Scher, J.S. 2002. Juniperus scopulorum. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
- U.S. Department of Agriculture, Forest Service, Missoula Fire Sciences Laboratory. 2012. Information from LANDFIRE on Fire Regimes of Western Great Plains Ash-Elm Communities. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture,
- Uchytil, R.J. 1991. Betula papyrifera. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
- Uresk, D.W., J. Javersak, and D.E. Mergen. 2009. Tree sapling and shrub heights after 25 years of livestock grazing in green ash draws in western North Dakota. In Proceedings of the South Dakota Academy of Science 88:99-108.
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