Print Report

A3466 Pinus ponderosa Northwest Great Plains Open Woodland Alliance

Type Concept Sentence: This very open to moderately dense (10-30% cover) Pinus ponderosa alliance sometimes has Quercus macrocarpa present to codominant in the tree canopy with the understory characterized by a sparse to dense herbaceous layer dominated by mixedgrass prairie species Andropogon gerardii, Pascopyrum smithii, and Schizachyrium scoparium occurring in foothills of the Black Hills and along escarpments, buttes, canyons, rock outcrops or ravines as an open woodland and grades into the mixedgrass prairie as a pine savanna in surrounding Great Plains.

Common (Translated Scientific) Name: Ponderosa Pine Northwest Great Plains Open Woodland Alliance

Colloquial Name: Northwest Great Plains Ponderosa Pine Open Woodland

Hierarchy Level:  Alliance

Type Concept: This alliance occurs in foothills of the Black Hills and along escarpments, buttes, canyons, rock outcrops or ravines as an open woodland and savanna in the surrounding mixedgrass prairie. The very open to moderate (10-30% cover) tree canopy is dominated by Pinus ponderosa, but may include a sparse to relatively dense subcanopy of Juniperus scopulorum and Quercus macrocarpa or other deciduous trees such as Acer negundo, Betula papyrifera, Fraxinus pennsylvanica, or Ulmus americana that are sometimes codominant with the pines, especially in mesic draws and swales. The understory is characterized by a sparse to dense herbaceous layer with species typifying the surrounding prairie group, with mixedgrass prairie species common, such as Andropogon gerardii, Bouteloua curtipendula, Pascopyrum smithii, and Schizachyrium scoparium. Soils typically range from well-drained loamy sands to sandy loams formed in colluvium, weathered sandstone, limestone, scoria or eolian sand.

Diagnostic Characteristics: This alliance is characterized by the dominance of Pinus ponderosa in an open to sparse (savanna) tree canopy with an understory characterized by a sparse to dense herbaceous layer composed of species typifying the surrounding prairie group, such as Andropogon gerardii, Bouteloua curtipendula, Carex inops ssp. heliophila, Carex filifolia, Elymus canadensis, Hesperostipa comata, Hesperostipa spartea, Koeleria macrantha, Muhlenbergia racemosa, Nassella viridula, Oryzopsis asperifolia, Pascopyrum smithii, Piptatheropsis micrantha, Schizachyrium scoparium, and Sporobolus heterolepis.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Currently ~Pinus ponderosa Limestone Cliff Sparse Vegetation (CEGL002055)$$ is placed in this alliance because cliffs are defined as having at least 3-m vertical height which is common on ridgetops, slopes and in drainage bottoms and rock outcrops in the breaks in the Great Plains and foothills. Cliffs are also common in the more mountainous montane zone in the Black Hills, so placement in ~Pinus ponderosa Dry-Mesic Black Hills Forest & Woodland Alliance (A3464)$$ could also be justified, especially since the understory in many stands is often characterized by sparse shrubs, including Prunus virginiana, Rhus trilobata, and Toxicodendron pubescens.

This alliance may also belong with M151, perhaps in its own group as a Pinus ponderosa Great Plains woodland type.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: This alliance is characterized by the dominance of needle-leaved evergreen trees in an open to sparse (savanna) tree canopy . Broadleaf trees may be present in the tree canopy or subcanopy. The understory is characterized by a sparse to dense herbaceous layer dominated by perennial graminoids species. Mosses and lichens can be conspicuous in some stands; thick litter and duff layers occur, as do rock outcrops on steep slopes.

Floristics: The very open to moderate (10-50% cover) tree canopy is dominated by Pinus ponderosa, but may include a sparse to relatively dense subcanopy of Juniperus scopulorum with just a few scattered Pinus ponderosa trees. Deciduous trees such as Acer negundo, Betula papyrifera, Fraxinus pennsylvanica, Quercus macrocarpa, and Ulmus americana are important component in some areas, especially mesic draws and swales, and are sometimes codominant with the pines. The understory is characterized by a sparse to dense herbaceous layer with species typifying the surrounding prairie group, with mixedgrass species common, such as Andropogon gerardii, Bouteloua curtipendula, Carex inops ssp. heliophila, Carex filifolia, Elymus canadensis, Hesperostipa comata, Hesperostipa spartea, Koeleria macrantha, Muhlenbergia racemosa, Nassella viridula, Oryzopsis asperifolia, Pascopyrum smithii, Piptatheropsis micrantha (= Piptatherum micranthum), Schizachyrium scoparium, and Sporobolus heterolepis. Scattered shrubs may be present individually or in patches, but typically do not form a distinct shrub layer. Common shrub species can include Amorpha canescens, Artemisia frigida, Mahonia repens, Prunus virginiana, Rhus trilobata, Spiraea betulifolia, Symphoricarpos albus, and Toxicodendron pubescens.

Dynamics:  Fire undoubtedly plays an important role in the dynamics of these dry forest communities. Ground layer species composition has much in common with grasslands (Thilenius 1972). Forests vary widely in canopy closure. Understory vegetation may change if canopy closure is allowed to proceed without fire (Hansen and Hoffman 1988).
Environmental Description:  This ponderosa pine alliance occurs in foothills of the Black Hills and along escarpments, buttes, canyons, rock outcrops or ravines in the woodland to grassland transition zone into the surrounding mixedgrass prairie in the northwestern Great Plains grassland. It is found on warm exposures in the northern portion of its range in southeastern Montana (Pfister et al. 1977), but is found on cool slopes and canyons in the drier portions of the Black Hills (Thilenius 1972) and in the Powder River Basin of Wyoming (Jones 1992b). Elevations are about 1220 m (4000 feet) in Montana, but 1460-1675 m (4800-5500 feet) in South Dakota. Thilenius (1972) reports that stands are in a 45- to 50-cm annual precipitation zone in the Black Hills. Stands in the Black Hills occur on "relatively deep" soils with near-neutral reaction (Thilenius 1972). Montana stands more likely occur on soils derived from sandstone. Stands are often surrounded by mixedgrass or tallgrass prairie, in places where available soil moisture is higher or soils are more coarse and rocky. In some cases, these woodlands or savannas may occur where fire suppression has allowed trees to become established (in areas where deciduous trees are more abundant (Girard et al. 1987)). These are typically not in the same setting as Rocky Mountain ponderosa pine, where ponderosa pine forms woodlands at lower treeline and grades into mixed montane conifer systems at higher elevations. These are physiognomically variable woodlands, ranging from very sparse patches of trees on drier sites, to nearly closed-canopy forest stands on north slopes or in draws where available soil moisture is higher. Soils typically range from well-drained loamy sands to sandy loams formed in colluvium, weathered sandstone, limestone, scoria or eolian sand.
Geographic Range: This woodland and savanna alliance occurs in the foothills of the Black Hills on rolling plains and escarpments in the northwestern Great Plains.

Nations: US

States/Provinces:  CO, MT, NE, NM, OK?, SD, WY


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: GNR

Greasons: No Data Available
Type Name Database Code Classification Code
Class 1 Forest & Woodland Class C01 1
Subclass 1.B Temperate & Boreal Forest & Woodland Subclass S15 1.B
Formation 1.B.2 Cool Temperate Forest & Woodland Formation F008 1.B.2
Division 1.B.2.Nb Rocky Mountain Forest & Woodland Division D194 1.B.2.Nb
Macrogroup 1.B.2.Nb.2 Ponderosa Pine - Douglas-fir - Limber Pine Central Rocky Mountain Dry Forest Macrogroup M501 1.B.2.Nb.2
Group 1.B.2.Nb.2.e Ponderosa Pine Northwestern Great Plains Forest & Woodland Group G216 1.B.2.Nb.2.e
Alliance A3466 Ponderosa Pine Northwest Great Plains Open Woodland Alliance A3466 1.B.2.Nb.2.e
Association CEGL000188 Ponderosa Pine / Western Wheatgrass Open Woodland CEGL000188 1.B.2.Nb.2.e
Association CEGL000201 Ponderosa Pine / Little Bluestem Open Woodland CEGL000201 1.B.2.Nb.2.e
Association CEGL000841 Ponderosa Pine / (Big Bluestem, Little Bluestem) Open Woodland CEGL000841 1.B.2.Nb.2.e
Association CEGL000873 Ponderosa Pine / Bur Oak Open Woodland CEGL000873 1.B.2.Nb.2.e
Association CEGL002055 Ponderosa Pine Limestone Cliff Sparse Vegetation CEGL002055 1.B.2.Nb.2.e
Concept Lineage: This alliance includes three associations from Old Alliance II.A.4.N.a. Pinus ponderosa Woodland Alliance (A.530) and one association from Old Alliance VII.A.1.N.a. Open Cliff Sparsely Vegetated Alliance (A.1836).

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: > Pinus ponderosa - Quercus macrocarpa / Prunus virginiana / Symphoricarpos albus / Mahonia repens (Thilenius 1972)
> Pinus ponderosa - Quercus macrocarpa / Prunus virginiana / Symphoricarpos albus / Schizachne purpurascens - Carex foenea (Thilenius 1972)
> Pinus ponderosa / Andropogon scoparius habitat unit (Thilenius 1972)
> Pinus ponderosa / Andropogon spp. Habitat Type (Pfister et al. 1977)
> Pinus ponderosa / Pascopyrum smithii Woodland (Marriott and Faber-Langendoen 2000)
> Pinus ponderosa / Quercus macrocarpa Habitat Type (Hoffman and Alexander 1987)
> Pinus ponderosa / Schizachyrium scoparium Community (Jones 1992b)
Concept Author(s): K.A. Schulz, in Faber-Langendoen et al. (2013)

Author of Description: K.A. Schulz

Acknowledgements: We have incorporated significant descriptive information previously compiled by Marion Reid.

Version Date: 01-08-14
  • Alexander, R. M. 1986. Classification of the forest vegetation of Wyoming. Research Note RM-466. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 10 pp.
  • Alexander, R. R. 1985. Major habitat types, community types, and plant communities in the Rocky Mountains. General Technical Report RM-123. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 105 pp.
  • Brown, R. W. 1971. Distribution of plant communities in southeastern Montana badlands. The American Midland Naturalist 85(2):458-477.
  • Cooper, S. V., and R. D. Pfister. 1985. Forest habitat types of the Crow and Northern Cheyenne Indian Reservations. Unpublished termination report prepared for Bureau of Indian Affairs, Billings Area Office by USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT. 118 pp.
  • Currie, P. O. 1975. Grazing management of ponderosa pine - bunchgrass ranges of the central Rocky Mountains: The status of our knowledge. Research Paper RM-159. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 24 pp.
  • Eyre, F. H., editor. 1980. Forest cover types of the United States and Canada. Society of American Foresters, Washington, DC. 148 pp.
  • Faber-Langendoen, D., J. Drake, M. Hall, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, L. Sneddon, K. Snow, and J. Teague. 2013-2019b. Screening alliances for induction into the U.S. National Vegetation Classification: Part 1 - Alliance concept review. NatureServe, Arlington, VA.
  • Faber-Langendoen, D., and Midwest State Natural Heritage Program Ecologists. 1996. Terrestrial vegetation of the midwest United States. International classification of ecological communities: Terrestrial vegetation of the United States. The Nature Conservancy, Arlington, VA.
  • Fischer, W. C., and B. D. Clayton. 1983. Fire ecology of Montana forest habitat types east of the Continental Divide. General Technical Report INT-141. USDA Forest Service, Intermountain Forest Range Experiment Station, Ogden, UT. 83 pp.
  • Girard, M. M., H. Goetz, and A. J. Bjugstad. 1987. Factors influencing woodlands of southwestern North Dakota. Prairie Naturalist 19(3):189-198.
  • Hansen, P. L., and G. R. Hoffman. 1988. The vegetation of the Grand River/Cedar River, Sioux, and Ashland districts of the Custer National Forest: A habitat type classification. General Technical Report RM-157. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 68 pp.
  • Hoffman, G. R., and R. R. Alexander. 1976. Forest vegetation of the Bighorn Mountains, Wyoming: A habitat type classification. Research Paper RM-170. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 38 pp.
  • Hoffman, G. R., and R. R. Alexander. 1987. Forest vegetation of the Black Hills National Forest of South Dakota and Wyoming: A habitat type classification. Research Paper RM-276. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 48 pp.
  • Jones, G. 1992b. Wyoming plant community classification (Draft). Wyoming Natural Diversity Database, Laramie, WY. 183 pp.
  • MacCracken, J. G., D. W. Uresk, and R. M. Hansen. 1983b. Plant community variability on a small area in southeastern Montana. Great Basin Naturalist 43(4):660-668.
  • MacCracken, J. G., L. E. Alexander, and D. W. Uresk. 1983a. An important lichen of southeastern Montana rangelands. Journal of Range Management 36(1):35-37.
  • Marriott, H. J., and D. Faber-Langendoen. 2000. The Black Hills community inventory. Volume 2: Plant community descriptions. The Nature Conservancy, Midwest Conservation Science Center and Association for Biodiversity Information, Minneapolis, MN. 326 pp.
  • Pfister, R. D., B. L. Kovalchik, S. F. Arno, and R. C. Presby. 1977. Forest habitat types of Montana. General Technical Report INT-34. USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT. 174 pp.
  • Potter, L. D., and D. L. Green. 1964. Ecology of ponderosa pine in western North Dakota. Ecology 45(1):10-23.
  • Progulske, D. R., and F. J. Shideler. 1974. Following Custer. South Dakota State University, Agricultural Experiment Station. Bulletin No. 674. Brookings. 139 pp.
  • Roberts, D. W. 1980. Forest habitat types of the Bear''s Paw Mountains and Little Rocky Mountains, Montana. Unpublished thesis, Department of Forestry, University of Montana, Missoula. 116 pp.
  • Thilenius, J. F. 1971. Vascular plants of the Black Hills of South Dakota and adjacent Wyoming. General Technical Report RM-71. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO.
  • Thilenius, J. F. 1972. Classification of the deer habitat in the ponderosa pine forest of the Black Hills, South Dakota. Research Paper RM-91. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, CO. 28 pp.