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A3431 Quercus stellata Interior Flatwoods Forest Alliance

Type Concept Sentence: These are flatwoods or clay barrens forests and woodlands found in the south-central United States and dominated by Quercus alba, Quercus bicolor, Quercus falcata, Quercus palustris, and Quercus stellata.


Common (Translated Scientific) Name: Post Oak Interior Flatwoods Forest Alliance

Colloquial Name: Interior Post Oak Flatwoods Forest

Hierarchy Level:  Alliance

Type Concept: This flatwoods or clay barrens forest and woodland alliance is found in the south-central United States. The canopy is typically strongly dominated by Quercus stellata, which is characteristic, but may also include Quercus alba, Quercus bicolor, Quercus falcata, Quercus marilandica, and, more rarely, Quercus palustris. In Illinois, the shrub and woody vine strata may contain Parthenocissus quinquefolia, Rosa carolina, Rubus allegheniensis, Rubus flagellaris, and Toxicodendron radicans. The herbaceous layer can be fairly disparate from one stand to the next. Some stands can be dominated by Cinna arundinacea, Chasmanthium latifolium, and Eleocharis tenuis var. verrucosa. Plants more typical of dry and dry-mesic soil grow on slight rises, including Carex festucacea, Carex pensylvanica, Danthonia spicata, Helianthus divaricatus, and others. Stunted trees are often present due to unfavorable soil conditions. Examples of this alliance occur on level or nearly level soil with a well-developed hardpan or argilic clay layer. This hardpan is an impermeable or nearly impermeable layer of subsoil that causes a shallowly perched water table. The hardpan impedes water percolation and subsoil recharge (stops movement of water up to the dry surface soil from deeper, more moist soil) in the summer, resulting in droughty conditions, and also slows drainage during wet periods. Stands are dominated by trees, but canopy closure is variable and dependent on disturbances such as fire and native grazing. In southern Illinois, stands of this alliance occur in very poorly drained areas with Quercus stellata the only abundant tree species, creating a cathedral-like overstory. The height growth of Quercus stellata trees stops when the trees reach about 30 cm in diameter, creating a maximum tree height of 22-23 m. At some sites, stunted trees may be present due to unfavorable soil conditions.

Diagnostic Characteristics: The unusual ecological setting (flatwoods and clay barrens) as well as the dominance by Quercus stellata and other Quercus species are distinctive and noteworthy.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: See Campbell and Grubbs (1992) for description of a Kentucky occurrence in Hopkins County, possibly in the Arkansas River Valley. Description of CEGL002405 states: "...understory composition may vary widely (Taft et al. 1995). In Kentucky, this type is thought to be fire-suppressed; structure varies from forest to woodland (M. Evans pers. comm. 1999). The former is thought to represent the fire-suppressed condition, the latter the more natural state, remnants of which still exist in the Jackson Purchase area [see Hendricks et al. (1991)]. Many noteworthy herbaceous species are characteristic of prairie barrens. Compare also with other Kentucky "Flatwoods" types. In Missouri stands also may contain a large prairie flora [see Ladd and Heumann (1994)]. See Taft et al. (1995) for an excellent review of this type in Illinois.''"

Similar NVC Types: No Data Available
note: No Data Available

Physiognomy and Structure: Stands are dominated by trees, but canopy closure is variable and dependent on disturbances such as fire and native grazing. Under current conditions, stands may be more closed due to a lack of disturbance. Loss of these natural processes often results in a shift toward a more closed canopy, an increase in successional woody species such as Juniperus spp., and a decrease in native grass cover. In southern Illinois, Quercus stellata is the only abundant tree species present, creating a cathedral-like overstory. The height growth of Quercus stellata trees stops when the trees reach about 30 cm in diameter, creating a maximum tree height of 22-23 m (Fralish 1988a). At some sites, stunted trees may be present due to unfavorable soil conditions.

Floristics: The canopy of this flatwoods or clay barrens forest or woodland is typically strongly dominated by Quercus stellata, which is characteristic, but may also include Quercus alba, Quercus bicolor, Quercus falcata, Quercus marilandica, and, more rarely, Quercus palustris. In Illinois, the shrub and woody vine strata may contain Parthenocissus quinquefolia, Rosa carolina, Rubus allegheniensis, Rubus flagellaris, and Toxicodendron radicans (Taft et al. 1995). In Indiana, shrubs include Rhus copallinum and Hypericum prolificum. The herbaceous layer can be fairly disparate from one stand to the next. Some stands can be dominated by Cinna arundinacea, Chasmanthium latifolium, and Eleocharis tenuis var. verrucosa (= Eleocharis verrucosa). Plants more typical of dry and dry-mesic soil grow on slight rises, including Carex festucacea, Carex pensylvanica, Danthonia spicata, Helianthus divaricatus, and others (Aldrich and Homoya 1986, Taft et al. 1995). In the Jackson Purchase region of Kentucky, Quercus velutina is important in the overstory (Hendricks et al. 1991). In Kentucky, the canopy may have Carya texana and Quercus alba. The herbaceous cover is sparse to moderate; leaf litter is the dominant ground cover. Local dominance in depressions is of wetland species (Juncus, etc.). Dry areas will have Croton michauxii var. ellipticus (= Croton willdenowii), Danthonia spicata, Manfreda virginica, Gillenia stipulata (= Porteranthus stipulatus), Pycnanthemum tenuifolium, and Prenanthes aspera (which is characteristic of open areas).

Dynamics:  Canopy closure is variable and dependent on disturbances such as fire and native grazing that played a role in historically maintaining an open structure in this vegetation. Under current conditions, stands may be more closed due to a lack of disturbance. Loss of these natural processes often results in a shift toward a more closed canopy, an increase in successional woody species such as Juniperus spp., and a decrease in native grass cover. Edaphic factors and variability in climate are also factors. This community typically borders floodplain forests and may be associated with barrens.

Environmental Description:  Stands of this alliance occur on level or nearly level soil with a well-developed hardpan. This hardpan is an impermeable or nearly impermeable layer of subsoil that causes a shallowly perched water table (White and Madany 1978). The hardpan stops movement of water up to the dry surface soil from deeper, more moist soil in the summer and slows drainage during wet periods. It also restricts rooting and burrowing depth. The soil moisture fluctuates widely throughout the growing season. Depressions often contain seasonal or ephemeral ponds. Vernal ponds are characteristic. Stands of this alliance usually are found over glacial till of Illinoisan age, but their distribution south of glacial deposits in Kentucky is uncertain. In southern Illinois, stands of this alliance occur in very poorly-drained areas (Fralish 1988a). In Kentucky, this community occurs on relatively high flat areas that are no longer flooded, such as ancient Quaternary or Tertiary post-glacial meltwater lakebeds and high terraces of the Upper Gulf Coastal Plain and Shawnee Hills. The stands grade downslope into bottomland hardwood forest and cypress swamp and upslope into mesic upland or dry oak-hickory forest.

Geographic Range: Examples of this alliance are found in the Ozarks, Interior Low Plateau, and adjacent interior regions of the south-central United States from Arkansas and Missouri and east to Kentucky.

Nations: US

States/Provinces:  AR, IL, IN, KY, MO




Confidence Level: Low

Confidence Level Comments: No Data Available

Grank: GNR

Greasons: No Data Available


Concept Lineage: This alliance contains two associations, one each from A.261 (1/1) and A.625 (1/36).

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: ? Quercus stellata - Cinna arundinacea type (Fralish 1988b)
>< IA6c. Dry Post Oak - Blackjack Oak Forest (Allard 1990)
? Post Oak - Blackjack Oak: 40 (Eyre 1980) [clayey, heavy soil variant]
? T2A2bI. Juniperus virginiana - Quercus spp. (Foti et al. 1994)
? T2B4aI1b. Quercus stellata - Quercus marilandica - Carya texana (Foti et al. 1994)

Concept Author(s): M. Pyne, in Faber-Langendoen et al. (2013)

Author of Description: M. Pyne

Acknowledgements: We thank the following for their contribution: Don Faber-Langendoen and Judy Teague

Version Date: 01-07-14

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