Physiognomy and Structure: Physiognomy of this vegetation ranges from closed forest to open woodland, with deciduous trees, needle-leaved trees, or a mixture of both. The shrub layer is often well-developed and characterized by heath shrubs in more infertile settings. Where this macrogroup occurs on the coast and on other highly exposed sites such as bedrock outcrops, steep slopes, and shale barrens, canopy trees may be stunted, gnarled, or wind-sheared. Tree canopies in coastal settings may also share dominance with tall shrubs and heavy vine cover.

Floristics: Acidic parent materials of low fertility support forests dominated by Quercus coccinea, Quercus falcata, Quercus montana (= Quercus prinus), Quercus velutina, as well as other hardwoods such as Liriodendron tulipifera, Nyssa sylvatica, Sassafras albidum, and pines, including Pinus pungens, Pinus rigida, Pinus strobus, and Pinus virginiana, often overtopping a well-developed heath shrub layer comprising species of Gaylussacia, Rhododendron, Vaccinium, and others. Castanea dentata is an important understory component. The herbaceous layer may be poorly developed where tree or shrub canopies are dense; typical species include Carex pensylvanica, Danthonia spicata, Deschampsia flexuosa, Gaultheria procumbens, and others.

Less acidic or neutral parent materials support many of the same oak species as on acidic parent materials, in combination with Carya spp., Betula alleghaniensis, Betula lenta, Fraxinus americana, and Fagus grandifolia. Shrubs and understory tree species can include Carpinus caroliniana, Cornus florida, Euonymus americanus, Hamamelis virginiana, Lindera benzoin, Oxydendrum arboreum, Viburnum acerifolium; typical species of the herb layer include Amphicarpaea bracteata, Arisaema triphyllum, Botrychium virginianum, Galium circaezans, Hexastylis arifolia, Hexastylis minor, Medeola virginiana, Mitchella repens, Parthenocissus quinquefolia, Polygonatum pubescens, Polystichum acrostichoides, and Thelypteris noveboracensis.

Quercus muehlenbergii and Acer saccharum are particularly characteristic of parent materials of higher base status. Typical shrub species in this setting may include Cercis canadensis, Viburnum prunifolium, and Viburnum rafinesqueanum. The herbaceous layer is more species-rich than in infertile sites, and include mesophytic species such as Actaea pachypoda, Adiantum pedatum, Aquilegia canadensis, Asclepias quadrifolia, Carex eburnea, Carex platyphylla, Dichanthelium boscii, Elymus hystrix, Hepatica nobilis, and Packera obovata.

Dynamics:  At moderate to low elevations, stands are naturally stable, uneven-aged forests, with canopy dynamics generally dominated by gap-phase regeneration. Wind or ice storms may create larger canopy openings. Fire occurred fairly frequently in pre-European-settlement times but much less so now. Higher-elevation examples may occur on exposed ridges where they are subject to frequent ice storms in the winter, windstorms in the summer, and high winds throughout the year. In pine barrens, fire is particularly important in arresting succession to hardwood dominance. Vegetation on highly exposed bedrock or very steep slopes may be edaphically controlled. In maritime situations, frequent storms, high winds, and salt spray impact physiognomy. Treefalls are common, causing canopy gaps and highly variable structure. Many of these forests were logged in early settlement, and when oaks were removed, their re-establishment was hampered by their slow growth in these exposed settings. They were replaced by fast-growing early-successional species with fruits and/or seeds that are either bird- or wind-dispersed. Heavy browsing by deer impact both the structure and composition of herbaceous and shrub layers, and can hamper tree regeneration. Outbreaks of southern pine beetle (Dendroctonus frontalis) can shift pine-dominated forests and woodlands to deciduous forest.