Physiognomy and Structure: No Data Available

Floristics: Vegetation of this type is an open- to closed-canopy, mixed hardwood forest dominated by oaks, hickories, and white ash. Stands over hardpans or shallow soils over bedrock have a somewhat stunted canopy. Quercus alba, Quercus rubra, Carya glabra, Carya ovalis, Carya tomentosa (= Carya alba), and Fraxinus americana are the leading overstory dominants in variable combinations. In the more western, submontane habitats, Quercus montana (= Quercus prinus) is often codominant. Quercus velutina, Quercus stellata, Quercus montana, Ulmus rubra, and Juglans nigra are occasional overstory associates. Subcanopy tree layers are usually dominated by young hickories and Fraxinus americana. Characteristic species in the shrub and small-tree layers are Cercis canadensis var. canadensis (dominant with up to 850 stems/ha in some areas), Juniperus virginiana var. virginiana, Cornus florida, Ulmus rubra, Celtis occidentalis, and Rosa carolina. Less constant, but sometimes locally important, understory species include Ostrya virginiana, Carpinus caroliniana (on more mesic sites), and Chionanthus virginicus. The herb layer of this community is frequently characterized by patch-dominance of the dry-site forest grasses Muhlenbergia sobolifera, Dichanthelium boscii, Elymus hystrix var. hystrix, and Danthonia spicata. Co-occurring among the dominant grasses are a large number of low-cover forbs and graminoids, among the most characteristic of which are Agrimonia rostellata, Amphicarpaea bracteata, Aristolochia serpentaria, Bromus pubescens, Carex digitalis, Carex hirsutella (= Carex complanata var. hirsuta), Desmodium nudiflorum, Festuca subverticillata, Galium circaezans, Geum virginianum, Houstonia purpurea var. purpurea, Maianthemum racemosum ssp. racemosum, Phryma leptostachya, Polygonatum biflorum, Sanicula canadensis, Scutellaria elliptica, Solidago caesia, Solidago ulmifolia var. ulmifolia, Thalictrum thalictroides, Uvularia perfoliata, and Viola triloba var. triloba (all of these with >50% constancy in 50 plots). Less constant species that are nevertheless locally abundant or characteristic include Antennaria plantaginifolia (2 vars.), Brachyelytrum erectum, Carex albicans var. australis, Carex pensylvanica, Carex planispicata, Clematis ochroleuca, Dichanthelium linearifolium, Galium concinnum, Helianthus divaricatus, Melica mutica, Piptochaetium avenaceum, and Pycnanthemum incanum. Patches of exposed mineral soil around tree bases are frequently occupied by a suite of diminutive annuals including Acalypha virginica, Hedeoma pulegioides, and Paronychia canadensis. Many additional species occur at low cover and/or constancy. In 50 Virginia plot samples, this unit has a mean species richness of 82 taxa per 400 m2, one of the highest among all classified upland types in Virginia. Additionally, a plot of this vegetation containing 125 taxa represents one of the most species-rich upland sample among >3300 plots in the VDNH database (VDNH unpubl. data).

Dynamics:  Historically, this association had a more extensive distribution in northern Virginia, but many stands have been destroyed by development sprawling from the Washington, DC, metropolitan area. Most of the remaining stands have been subject to various anthropogenic disturbances, including cutting, conversion to pine silviculture, and grazing. Excessive deer browse, resulting in reduced tree recruitment and dwarfing of repeatedly grazed herbaceous species, is a serious problem in almost all stands. The rather dry soils occupied by this community keep many exotic plants in check, but the drought-tolerant Lonicera japonica, Poa compressa, and Symphoricarpos orbiculatus (a shrub naturalized from the western U.S.) are problematic invaders. Stands on the most mesic sites are vulnerable to invasion by Microstegium vimineum and Alliaria petiolata. The fungal pathogen Discula destructiva (dogwood anthracnose) is now rampant in virtually all stands of this type and has caused extensive mortality of the former understory codominant Cornus florida.