Print Report
G181 Quercus macrocarpa - Quercus velutina / Andropogon gerardii Savanna & Barrens Group
Type Concept Sentence: The deep-loam to sandy oak savanna (oak openings and oak barrens) occurs in the tallgrass prairie regions of the central United States, where scattered trees (10 to 30% cover) occur over a more-or-less continuous tallgrass prairie layer. Trees are Populus tremuloides, Quercus alba, Quercus bicolor, Quercus macrocarpa, and/or Quercus stellata, and dominant graminoids include Andropogon gerardii, Schizachyrium scoparium, Sorghastrum nutans, Sporobolus heterolepis, and/or Hesperostipa spartea.
Common (Translated Scientific) Name: Bur Oak - Black Oak / Big Bluestem Savanna & Barrens Group
Colloquial Name: Central Midwest Oak Openings & Barrens
Hierarchy Level: Group
Type Concept: The deep-soil oak savanna occurs in the northern, central and southern tallgrass prairie regions of the central United States, with extensions into southern Ontario and southeastern Manitoba, Canada. It was historically dominant in the northern glaciated regions of the Midwest with the largest concentration in the prairie-forest border ecoregion. It is typically found on rolling outwash plains, hills and ridges. Soils are typically moderately well- to well-drained deep loams. This savanna is typified by scattered trees, varying from 10 to 30% cover over a more-or-less continuous tallgrass prairie layer. Quercus macrocarpa is a common tree throughout the range. Other associates include Populus tremuloides (northern portion of the range), Quercus alba, Quercus bicolor, and Quercus stellata. The dominant herbaceous species are the graminoids Andropogon gerardii, Schizachyrium scoparium, Sorghastrum nutans, Sporobolus heterolepis, and Hesperostipa spartea. A rich forb component includes Amorpha canescens, Antennaria spp., Calamagrostis canadensis (in moist stands), Carex spp., Lespedeza capitata, Ratibida pinnata, Silphium laciniatum, and Zizia aurea, among many species. The shrub layer can be absent to prominent. Where shrubs are present, Corylus spp. tend to be dominant, accompanied by species such as Cornus foemina, Rosa spp., Rubus allegheniensis, and Symphoricarpos occidentalis (in the west). Historically, frequent fires maintained this savanna within its range and would have restricted tree canopies to 10-30% cover. Fire suppression in the region has allowed trees to establish more dense canopies. Periodic, strong wind disturbances and browsing also impact this type. Much of this type has also been converted to agriculture, or succeeded to forests because of the lack of fire, greatly reducing its area and range.
The sandy oak barrens occur on well-drained, coarse-textured sandy soils derived from glacial outwash, end moraine formations, or lakeplain dune systems in the north-central U.S. and parts of southern Ontario, Canada. Soils range from almost pure sand, to loamy sand, to sandy loam. The soils have low fertility, organic matter, and moisture-retention capacity. Factors which affect seasonal soil moisture are strongly related to variation in this type. The oak barrens is a scrubby, open-treed system dominated by graminoids and shrubs. Canopy structure varies from a dominant herbaceous ground layer with sparse, scattered "savanna" canopy (5-25%), through oak-dominated scrub, to a more closed woodland canopy (25-60%). The canopy layer is dominated by Quercus velutina, with some Quercus ellipsoidalis, Quercus macrocarpa, and Quercus alba (the latter more common eastward and in woodland conditions). Occasional Pinus banksiana can occur in the northern parts of the range. Species found in the herb layer include Ambrosia psilostachya, Amphicarpaea bracteata, Artemisia ludoviciana, Andropogon gerardii, Calamovilfa longifolia, Carex pensylvanica, Carex spp., Comandra umbellata, Sorghastrum nutans, Hesperostipa spartea, and Schizachyrium scoparium. Fire was an important factor in maintaining this community. Oak wilt and droughts also reduce tree cover.
The sandy oak barrens occur on well-drained, coarse-textured sandy soils derived from glacial outwash, end moraine formations, or lakeplain dune systems in the north-central U.S. and parts of southern Ontario, Canada. Soils range from almost pure sand, to loamy sand, to sandy loam. The soils have low fertility, organic matter, and moisture-retention capacity. Factors which affect seasonal soil moisture are strongly related to variation in this type. The oak barrens is a scrubby, open-treed system dominated by graminoids and shrubs. Canopy structure varies from a dominant herbaceous ground layer with sparse, scattered "savanna" canopy (5-25%), through oak-dominated scrub, to a more closed woodland canopy (25-60%). The canopy layer is dominated by Quercus velutina, with some Quercus ellipsoidalis, Quercus macrocarpa, and Quercus alba (the latter more common eastward and in woodland conditions). Occasional Pinus banksiana can occur in the northern parts of the range. Species found in the herb layer include Ambrosia psilostachya, Amphicarpaea bracteata, Artemisia ludoviciana, Andropogon gerardii, Calamovilfa longifolia, Carex pensylvanica, Carex spp., Comandra umbellata, Sorghastrum nutans, Hesperostipa spartea, and Schizachyrium scoparium. Fire was an important factor in maintaining this community. Oak wilt and droughts also reduce tree cover.
Diagnostic Characteristics: A scattered canopy, typically 5-25% cover, dominated by either Quercus macrocarpa or Quercus velutina, with a strong graminoid layer of Andropogon gerardii and Schizachyrium scoparium, diverse herbs, and either deep loams or sandy-gravelly soils.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Oak barrens are closely related to sand and gravel prairie and barrens, and oak savanna (oak openings) are closely related to loamy tallgrass prairie, suggesting that this group could be split into two. These oak openings and barrens are often treated with prairie. For an example of this approach, see Minnesota DNR (2005) which treats southern dry savanna (oak barrens) and southern dry prairie together, and mesic savanna and mesic prairie together, and does the same for northern prairie and savanna types. If we followed that approach, an alternative arrangement of this group would be to disperse it among the closely related prairie and sand barren types, as follows: ~Central Lowlands Tallgrass Prairie Macrogroup (M054)$$ containing ~Northern Tallgrass Prairie Group (G075)$$, ~Central Tallgrass Prairie Group (G333)$$, and ~Southern Tallgrass Prairie Group (G334)$$. However, in Curtis (1959, pp. 568-571), the most closely related type to the oak openings was the oak barrens and vice versa.
The oak barrens physiognomy is complex. Black oak woodland variants may occur in this group, but because Quercus velutina and Quercus ellipsoidalis can sprout after stems have been killed by fires, stands generally have a somewhat scrubby structure that can vary from 5-60% cover over time. Some stands may occur on fairly mesic sands. Similar complex physiognomies are found in ~Laurentian-Acadian Pine - Hardwood Forest & Woodland Macrogroup (M159)$$, including ~Great Lakes Pine Barrens Group (G160)$$ and ~Pitch Pine Barrens Group (G161)$$.
Our concept of oak barrens includes the "Eastern Sand Savanna" and "Northern Sand Savanna - oak only" types of Will-Wolf and Stearns (1999), but we treat their "Northern Sand Savanna - oak-pine" with ~Great Lakes Pine Barrens Group (G160)$$. Our approach follows that of Curtis (1959).
The oak barrens physiognomy is complex. Black oak woodland variants may occur in this group, but because Quercus velutina and Quercus ellipsoidalis can sprout after stems have been killed by fires, stands generally have a somewhat scrubby structure that can vary from 5-60% cover over time. Some stands may occur on fairly mesic sands. Similar complex physiognomies are found in ~Laurentian-Acadian Pine - Hardwood Forest & Woodland Macrogroup (M159)$$, including ~Great Lakes Pine Barrens Group (G160)$$ and ~Pitch Pine Barrens Group (G161)$$.
Our concept of oak barrens includes the "Eastern Sand Savanna" and "Northern Sand Savanna - oak only" types of Will-Wolf and Stearns (1999), but we treat their "Northern Sand Savanna - oak-pine" with ~Great Lakes Pine Barrens Group (G160)$$. Our approach follows that of Curtis (1959).
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: The deep-soil oak savanna is typified by scattered trees over a continuous tallgrass prairie layer, comprised of both forbs and grasses. Fire suppression in the region has allowed trees to establish more dense canopies. The sandy oak barrens is a scrubby, open-treed system dominated by graminoids and shrubs. Canopy structure varies from a dominant herbaceous ground layer with sparse, scattered "savanna" canopy (5-25% cover), through oak-dominated scrub, to a more closed woodland canopy (25-60%). Leach and Givnish (1999) found that, in southern Wisconsin, oak savannas are forb-dominated, except on the sandiest or sunniest microsites.
Floristics: Ground layer composition of this group is strongly related to the changes in texture from sandy to silty sites (Leach and Givnish 1999). The silty loam, deeper-soil savanna is typified by scattered trees, varying from 10 to 30% cover over a more-or-less continuous tallgrass prairie layer. Quercus macrocarpa is a common tree throughout the range. Other associates include Populus tremuloides (northern portion of the range), Quercus alba, Quercus bicolor, and Quercus stellata. The dominant herbaceous species are the graminoids, though a gradient from graminoid to forb may occur in relation to increasing canopy cover, that include Andropogon gerardii, Schizachyrium scoparium, Sorghastrum nutans, Sporobolus heterolepis, and Hesperostipa spartea (= Stipa spartea). A rich forb component includes Amorpha canescens, Antennaria spp., Calamagrostis canadensis (in moist stands), Carex spp., Lespedeza capitata, Ratibida pinnata, Silphium laciniatum, and Zizia aurea. The shrub layer can be absent to prominent. Where shrubs are present, Corylus spp. tend to be dominant, accompanied by species such as Cornus foemina, Rosa spp., Rubus allegheniensis, and Symphoricarpos occidentalis (in the west). In the open tree layer, Quercus macrocarpa is the most common tree species and can range from 10-60% cover. The main herb layer is dominated by tallgrass prairie species such as Andropogon gerardii, Calamagrostis canadensis, and Schizachyrium scoparium, along with numerous forb species. (Curtis 1959, Anderson and Bowles 1999, Leach and Givnish 1999)
In the sandy oak barrens, the canopy layer is dominated by Quercus velutina, with some Quercus ellipsoidalis, Quercus macrocarpa, and Quercus alba (the latter more common eastward and in woodland conditions). Occasional Pinus banksiana can occur in the northern parts of the range. In the southern part of the range in central Illinois, sand savannas may be dominated by Quercus marilandica and Quercus velutina, with Carya texana. Species found in the herb layer include Ambrosia psilostachya, Amphicarpaea bracteata, Artemisia ludoviciana, Andropogon gerardii, Calamovilfa longifolia, Carex pensylvanica, Carex spp., Comandra umbellata, Sorghastrum nutans, Hesperostipa spartea, and Schizachyrium scoparium.
In the sandy oak barrens, the canopy layer is dominated by Quercus velutina, with some Quercus ellipsoidalis, Quercus macrocarpa, and Quercus alba (the latter more common eastward and in woodland conditions). Occasional Pinus banksiana can occur in the northern parts of the range. In the southern part of the range in central Illinois, sand savannas may be dominated by Quercus marilandica and Quercus velutina, with Carya texana. Species found in the herb layer include Ambrosia psilostachya, Amphicarpaea bracteata, Artemisia ludoviciana, Andropogon gerardii, Calamovilfa longifolia, Carex pensylvanica, Carex spp., Comandra umbellata, Sorghastrum nutans, Hesperostipa spartea, and Schizachyrium scoparium.
Dynamics: Oak savanna: Historically, frequent fires maintained this savanna within its range and would have restricted tree canopies to 10-30% cover. Fire suppression in the region has allowed trees to establish more dense canopies. Periodic, strong wind disturbances and browsing also impact this type. Much of this type has also been converted to agriculture, or succeeded to forests because of the lack of fire, greatly reducing its area and range. Oak barrens: Fire was an important factor in maintaining this community. Oak wilt and droughts also reduce tree cover (Curtis 1959, Will-Wolf and Stearns 1999).
Environmental Description: Oak savannas are typically found on rolling outwash plains, hills and ridges. Soils are typically moderately well- to well-drained deep loams. Oak barrens occur on well-drained, coarse-textured sandy soils derived from glacial outwash, end moraine formations, or lakeplain dune systems. Soils range from almost pure sand, to loamy sand, to sandy loam. The soils have low fertility, organic matter, and moisture-retention capacity. Factors which affect seasonal soil moisture are strongly related to variation in this type.
Geographic Range: The oak savanna is found throughout the northern glaciated regions of the Midwest. Its main concentration, where it was likely the matrix type, is within the prairie-forest border of Minnesota, Wisconsin, Iowa, and Illinois. Conversion to agriculture and fire suppression have significantly impacted its range. The oak barrens are found in the north-central U.S. from North Dakota to western New York and westernmost Pennsylvania (mostly historic there) and into Ontario, Canada.
Nations: CA,US
States/Provinces: IA, IL, IN, MB, MI, MN, MO, ND, NE, NY, OH, ON, PA, SD, WI
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.837682
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.Na Eastern North American Forest & Woodland Division | D008 | 1.B.2.Na |
| Macrogroup | 1.B.2.Na.4 White Oak - Bur Oak - Shagbark Hickory Forest, Woodland & Savanna Macrogroup | M012 | 1.B.2.Na.4 |
| Group | 1.B.2.Na.4.a Bur Oak - Black Oak / Big Bluestem Savanna & Barrens Group | G181 | 1.B.2.Na.4.a |
| Alliance | A1492 Black Oak - Northern Pin Oak Wooded Grassland Alliance | A1492 | 1.B.2.Na.4.a |
| Alliance | A3256 Bur Oak - White Oak Wooded Grassland Alliance | A3256 | 1.B.2.Na.4.a |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: > Oak Barrens (Curtis 1959)
> Oak Openings (Curtis 1959)
> Oak Openings (Curtis 1959)
- Albert, D. A. 1995b. Regional landscape ecosystems of Michigan, Minnesota, and Wisconsin: A working map and classification. General Technical Report NC-178. USDA Forest Service, North Central Forest Experiment Station, St. Paul, MN. 250 pp. plus maps.
- Anderson, R. C., and M. L. Bowles. 1999. Deep-soil savannas and barrens of the midwestern United States. Pages 155-170 in: R. C. Anderson, J. S. Fralish, and J. M. Baskin, editors. Savannas, barren, and rock outcrop plant communities of North America, Cambridge University Press.
- Comer, P. J., D. A. Albert, and M. Austin (cartography). 1998. Vegetation of Michigan circa 1800: An interpretation of the General Land Office Surveys 1816-1856. Michigan Natural Features Inventory, Lansing, MI. 2-map set, scale: 1:500,000.
- Curtis, J. T. 1959. The vegetation of Wisconsin: An ordination of plant communities. Reprinted in 1987. University of Wisconsin Press, Madison. 657 pp.
- Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- Kost, M. A., D. A. Albert, J. G. Cohen, B. S. Slaughter, R. K. Schillo, C. R. Weber, and K. A. Chapman. 2007. Natural communities of Michigan: Classification and description. Report No. 2007-21, Michigan Natural Features Inventory, Lansing. 314 pp. [http://web4.msue.msu.edu/mnfi/reports/2007-21_Natural_Communites_of_Michigan_Classification_and_Description.pdf]
- Leach, M. K., and T. J. Givnish. 1999. Gradients in the composition, structure, and diversity of remnant oak savannas in southern Wisconsin. Ecological Monographs 69:353-374.
- Minnesota DNR [Minnesota Department of Natural Resources]. 2005b. Field guide to the native plant communities of Minnesota: The Prairie Parkland and Tallgrass Aspen Parklands provinces. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul.
- Will-Wolf, S., and F. Stearns. 1999. Dry soil oak savanna in the Great Lakes region. Pages 135 -154 in: R. C. Anderson, J. S. Fralish, and J. M. Baskin, editors. Savannas, barren, and rock outcrop plant communities of North America. Cambridge University Press.