I. FOREST
I.B.2.N.e. Seasonally flooded cold-deciduous forest
I.B.2.N.e.15. QUERCUS PHELLOS SEASONALLY FLOODED FOREST ALLIANCE
Willow Oak Seasonally Flooded Forest Alliance

Concept: Forests in this alliance have seasonally flooded hydrology and are typically dominated or codominated by Quercus phellos. Other canopy species that frequently occur in these forests are Quercus lyrata, Quercus nigra, Quercus laurifolia (within its range), Quercus similis (within its range), Quercus texana (within its range), Quercus bicolor (within its range), Nyssa biflora, Liquidambar styraciflua, Ulmus americana, and in the northern extension of its range, Celtis laevigata var. laevigata and Fraxinus pennsylvanica. The subcanopy and shrub layers are poorly developed. Common species of these strata are Acer rubrum, Ilex decidua, Fraxinus caroliniana, Salix nigra, and Viburnum nudum var. nudum. Some other characteristic herbs of these forests include Boehmeria cylindrica, Saururus cernuus, Onoclea sensibilis, Carex joorii, Carex striata, Carex intumescens, Saccharum baldwinii, Juncus coriaceus, Trachelospermum difforme, Cinna arundinacea, Chasmanthium sessiliflorum, Rhynchospora glomerata, and Osmunda cinnamomea. Sphagnum spp. may be common, especially Sphagnum lescurii. This alliance occurs in upland depressions and swales in flatwoods that do not receive overbank flooding. In addition, some associations in this alliance are described from depressions in floodplains, but these may more appropriately placed in the related alliance, Quercus (laurifolia, phellos) Seasonally Flooded Forest Alliance (A.327). The flooding is seasonal in all these environments, but the hydroperiod may be longer or shorter depending on the situation. Some examples typically have longer hydroperiods than Quercus phellos-dominated communities in floodplain terraces. This alliance is found in the central and southeastern United States. Its component associations are distributed from the West Gulf Coastal Plain of Arkansas and Texas through the Gulf Coastal Plain, and north in the Atlantic Coastal Plain and Piedmont to Virginia. They also occur in the Interior Low Plateau of Tennessee and Kentucky, the Cumberland Plateau of northern Alabama, and the Mississippi River Alluvial Plain north to southern Illinois.

Comments: Consider splitting this alliance (T. Foti pers. comm.). There are types associated with a variety of environments. These include upland depressions, ponds, flatwoods, and depressions in floodplains.

Range: This alliance is found in southern Illinois, southeastern Missouri, Alabama, Arkansas, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Delaware, Maryland, and Virginia.

States/Provinces: AL AR GA IL KY LA MD? MO? MS? NC OK? SC TN TX VA

TNC Ecoregions: 38:C, 39:P, 40:C, 41:C, 42:C, 43:?, 44:C, 50:C, 52:C, 53:C, 56:P, 57:C, 58:C, 62:P

USFS Ecoregions: 221Hc:CCC, 221He:CCC, 222Af:CCC, 222Cb:CCC, 222Da:CCC, 222Eb:CCC, 222Eh:CCC, 231Aa:CCC, 231Ae:CCC, 231Ah:CC?, 231Ai:CC?, 231Aj:CC?, 231Ak:CC?, 231Ao:CCC, 231Ap:CCC, 231Ba:CC?, 231Bc:CC?, 231Bd:CC?, 231Bj:CCC, 231Bl:CC?, 231Cd:CCC, 231Cf:CCC, 231Da:CCC, 231Dc:CCC, 231Ea:CCC, 231Eb:CC?, 231Ec:CC?, 231Ed:CC?, 231Ee:CC?, 231Ef:CCC, 231Eg:CC?, 231Eh:CCC, 231Ei:CCC, 231Ej:CCC, 231Ek:CC?, 231El:CC?, 231Em:CC?, 231En:CC?, 231Ga:CCC, 231Gb:CC?, 231Gc:CCC, 232A:CP, 232Ba:CCP, 232Bb:CCP, 232Bc:CCP, 232Bd:CCP, 232Bh:CCP, 232Bj:CCP, 232Bk:CCP, 232Bl:CCP, 232Bm:CCP, 232Bn:CCP, 232Bo:CCP, 232Bp:CCP, 232Bq:CCP, 232Br:CCP, 232Bs:CCC, 232Bt:CCP, 232Bu:CCP, 232Bv:CCP, 232Bx:CCP, 232Bz:CCC, 232Ca:CCP, 232Cb:CCP, 232Cc:CCP, 232Cf:CCP, 232Cg:CCP, 232Ch:CCP, 232Cj:CCP, 232Fa:CC?, 232Fb:CC?, 232Fc:CC?, 232Fd:CCC, 232Fe:CCC, 234Aa:CCC, 234Ab:CCP, 234Ac:CCC, 234Ad:CCC, 234Ae:CCP, 234Af:CCP, 234Ag:CCC, 234Ah:CCC, 234Ai:CCP, 234Aj:CCP, 234Ak:CCP, 234Al:CCP, 234Am:CCC, 234An:CCP, 255:C, M221Cd:CCC, M231Aa:CCC, M231Ac:CCC

Federal Lands: COE (Bayou Bodcau); DOD (Arnold, Barksdale, Louisiana Army Ammunition Plant); NPS (Chickamauga-Chattanooga, Congaree Swamp, Shiloh?); USFS (Angelina, Bankhead, Bienville?, Chattahoochee, Daniel Boone, Davy Crockett, Delta?, De Soto?, Holly Springs?, Homochitto?, Kisatchie, Oconee, Ouachita, Ozark, Sabine NF, Sam Houston, St. Francis?, Tombigbee?, Tuskegee?, Uwharrie); USFWS (Big Lake?, Cossatot River?, Eufaula, Felsenthal?, Holla Bend?, Little River, Overflow?, Pond Creek?, Upper Ouachita?, White River NWR?)

Synonymy: IIA10d. Upland Depression Swamp, in part (Allard 1990); Willow Oak Forest (Foti 1994b); Sagpond Forest (Ambrose 1990a); Xerohydric flatwoods, in part (Evans 1991); Depression swamp. ? in part (Evans 1991); Nonriverine Willow Oak Flatwoods (Smith 1996a); Upland Depression Swamp Forest (Schafale and Weakley 1990); P1B3cVII. Quercus phellos (Foti et al. 1994); Flatwood Depression Forest (Smith 1996b); Willow Oak - Water Oak - Diamondleaf (Laurel) Oak: 88, in part (Eyre 1980); Sweetgum - Willow Oak: 92 (Eyre 1980); Willow Oak - Laurel Oak / Bignonia Loamy/Clayey Seasonally Flooded River Floodplains, in part (Turner et al. 1999)

References: Allard 1990, Ambrose 1990a, Evans 1991, Eyre 1980, Faber-Langendoen et al. 1996, Foti 1994b, Foti et al. 1994, Foti pers. comm., Klimas 1988b, Nelson 1985, Schafale and Weakley 1990, Smith 1996a, Smith 1996b, Turner et al. 1999, Voigt and Mohlenbrock 1964, Wharton et al. 1982, White and Madany 1978

Authors: A.S. WEAKLEY, MP, Southeast Identifier: A.330

Concept: This association is found in isolated, extensive upland depressions, in Delmarva bays in Accomack County, Virginia. The vegetation is characterized by mixed canopies of Quercus phellos, Quercus michauxii, Quercus pagoda, Quercus palustris, and/or Quercus alba. In addition, Acer rubrum, Nyssa sylvatica, Liquidambar styraciflua, and Pinus taeda are minor or understory trees. Shrubs (sparse to open) include Morella cerifera (= Myrica cerifera), Cephalanthus occidentalis, Itea virginica, Clethra alnifolia, Rhododendron viscosum, Lyonia ligustrina var. foliosiflora, Leucothoe racemosa, Smilax rotundifolia, Vaccinium corymbosum, and Vaccinium formosum. In the herbaceous layer, Carex striata var. brevis is the overwhelming herbaceous dominant (25-75% cover), with Carex bullata also abundant (25-50% cover) in some examples. Minor herbaceous associates include Woodwardia virginica, Woodwardia areolata, Euthamia graminifolia, Pluchea foetida, Scirpus cyperinus, and Rhexia mariana. The stands apparently cover many hectares and are associated with slight depressions with drainage impeded by an impermeable clay layer about half a meter below the soil surface. The habitat apparently has a seasonally high water table but ponds water only intermittently or for short periods.

Comments: This vegetation has been documented by Bill Moorhead (VANHP), who investigated several of the large, elliptical depressions that dot the flat landscape in Accomack County. There are three plots that document this vegetation, at two sites: "Dahl Swamp" and "The Lake" (G. Fleming pers. comm.). The stands apparently cover many hectares and are associated with slight depressions with drainage impeded by an impermeable clay layer about half a meter below the soil surface. The habitat apparently has a seasonally high water table but ponds water only intermittently or for short periods. Most of the areas seen by Bill Moorhead had been logged some decades ago and had a very open (woodland-like) physiognomy due to poor restocking of canopy trees. However, he also obtained information from local people that one of the areas was known historically as "savanna land," suggesting that fire and hydrology maintained a woodland physiognomy in the depressions (G. Fleming pers. comm.).

Range: This association is restricted to isolated upland pools in Delmarva bays in Accomack County, Virginia.

States/Provinces: MD?, VA:S?

TNC Ecoregions: 58:C

USFS Ecoregions: 232Bz:CCC

References: Fleming et al. 2001, Fleming pers. comm.

Authors: SCS Confidence: 2 Identifier: CEGL004644

- Maryland Vegetation Classification Subset Report I.B. Deciduous forest

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