State 1
Reference State - Upland Oak/Hickory Forest

The reference state for this ecological site is characterized by a closed-canopy hardwood forest dominated by oaks and hickories. In order for this reference state to be maintained, the oak/hickory species must be present in multiple age classes. In most cases red maple, sugar maple and American beech are colonizing the midstory and understory. A species composition shift toward these more mesophytic species is widely recognized throughout the eastern United States (McEwan et al., 2011). The reference state described here represents a condition dependent on complex, multiple disturbances, some of which are human caused. In order to get oak to succeed and recruit into the next stand, advanced oak regeneration must be present before a major canopy disturbance. Oaks must be able to reach a size that is competitive (through smaller-scale disturbances such as fire or herbicide of midstory, or tree planting with vigorous seedlings or saplings), then there needs to be a canopy disturbance. There may need to be additional disturbances to get rid of competition.

Community 1.1
White oak - pignut hickory

This phase is dominated by oaks and hickories in the overstory currently, but mid-story composition is shifting toward more shade and moisture-loving species. The understory is relatively rich in herbaceous diversity (including vines) but tree regeneration overwhelmingly favors the shade-tolerant species. For this phase to regenerate back to oak and hickory, numerous complex and site-specific factors may be necessary. These include acorn production, seedling establishment, advanced regeneration from seedlings, and timely release (Brose et al., 2013). Several types of management can be employed to this end including prescribed fire, mechanical and chemical competition control, site preparation, and planting. However, depending on the stand and its history, management for oak/hickory is typically intensive and often requires multiple treatments over time (~10 - 25 years), (Loftis, 2004). Without intensive management, in most cases, stands will naturally succeed to a more mesophytic forest type dominated by shade tolerant species (the maples and American beech). Dendroecology studies in nearby, very similar old-growth forest stands indicate that oak species have dominated stands for the past 300 years. They speculate that the recent proliferation of maples in the understory will inhibit regeneration of oak and pine under the current disturbance regime (Hart et al., 2012). Oak and hickory can regenerate in canopy gaps formed by uprooted trees, but only on very dry sites, indicating that gap-phase dynamics will favor maple overall (Hart and Kupfer, 2011). The American chestnut was an important part of this ecological site prior to decimation by the chestnut blight, but it is unclear how abundant it would have been. Colloquial estimates based on local names like "Chestnut Ridge" indicate that it may have been prolific. Sprouts from old chestnut stumps were noted often during field sampling. Sprouts rarely survive to flowering age, but can often reach as much as 8 inches diameter at breast height (DBH) before they succumb to the blight. Rarely, an American chestnut sprout will reach larger size classes and survive to flower.

Forest overstory. The overstory of this community is dominated by oak and hickory species, most commonly white oak and pignut hickory. Other species include tuliptree, black oak, northern red oak, chestnut oak, blackjack oak, shagbark hickory (Carya carolinae-septentrionalis), mockernut hickory (Carya alba), scarlet oak (Quercus coccinea) and blackgum (Nyssa sylvatica), among others.

Midstory species include sourwood (Oxydendrum arboreum), sassafras (Sassafras albidum), eastern redbud (Cercis canadensis), flowering dogwood (Cornus florida), Carolina buckthorn (Frangula caroliniana), and common serviceberry (Amelanchier arborea). Shade tolerant hardwoods are a natural part of the dynamic of this ecological site, but have become more dominant in the midstory of most stands than they might naturally be due to lack of disturbance over time. Shade tolerant species include American beech, sugar maple and red maple.

Please note that species are reported by height class. Some species occur in multiple height classes, and accordingly, have multiple entries.

Forest understory. Herbaceous diversity is high overall, but not as high as in other associated ecological sites (not yet described). Occurrence and abundance vary based on topography and are lowest on ridges and south-facing shoulders and side slopes and highest on lower north-facing side slopes. Commonly occurring species include feathery false lily of the valley (Maianthemum racemosum), littlebrownjug (Hexastylis arifolia), mayapple (Podophyllum peltatum), cutleaf toothwort (Cardamine concatenata), the bellworts (Uvularia spp.), American cancer root (Conopholis americana), trefoil (Desmodium spp.), jack in the pulpit (Arisaema triphyllum), sweet cicely (Osmorhiza spp.), trailing arbutus (Epigaea repens), the violets (Viola spp.), wood sorrel (Oxalis montana), black cohosh (Actaea racemosa), forest licorice bedstraw (Calium circaezans), and yellow wakerobin (Trillium luteum).

Native vines are important in this ecological site; although, it is unclear how much disturbance plays a role in their abundance. Poison ivy (Toxicodendron radicans), for example, tends to do better in disturbed areas and can often be an indication of a past disturbance, such as grazing, if found in proliferation. Other important vines include greenbriar (Smilax spp.), muscadine (Vitis rotundifolia), Virginia creeper (Parthenocissus quinquefolia), and crossvine (Bignonia capreolata).

Community 1.2
Maple species - American beech

This community phase has not yet been attained in most cases because forests currently dominated by oaks and hickories are in transition. Without management or large-scale disturbance, stands will naturally succeed to more mesophytic species composition in the overstory and the oaks and hickories will lose their dominance over time. Small-scale gap dynamics caused by tree throws would likely be a natural part of this state and would favor the maple component in forest stands (Hart et al. 2012). A recent study of red maple on the nearby Cumberland Plateau found that canopy accession strategy and climate-growth relationships are critical factors in the shift from state 1.1 to state 1.2 (Hart et al., 2012). Red maples are gap-opportunists and can take advantage of smaller-scale disturbances such as tree-throws. Oaks in contrast, seem to have needed high frequency, intense disturbances to establish their current dominance in the forest. Red maples do best in times of cool, wet springs preceded by wet autumns and warm winters (Hart et al. 2012). Depending on climate conditions in the coming years, the weather may or may not favor their continued establishment. Red maple might also cause local environmental changes that facilitate perpetuation of favorable conditions for regeneration such as modification of understory light levels and soil characteristics (Nowacki and Abrams 2008). The denser canopies might reduce understory temperature and increase relative humidity, which would also favor the more shade-tolerant, moisture loving state (Alexander and Arthur 2010). Prescribed fire has been suggested as a management tool to reverse the trend. While it may be a useful tool in some cases and most likely in combination with other management approaches, using fire alone is unlikely to produce the desired results in most stands (Clark and Schweitzer 2013).

Forest overstory. The forest overstory is dominated by mature maples and American beech. Tree throws create small-scale gap dynamics in the forest, which favor recruitment of the maples and in some cases, yellow poplar. Oaks and hickories will always be a part of the species composition in this state, but will not be dominant.

Forest understory. Forest understory composition will be similar to community phase 1.1, dominated by native herbs, forbs, and vines. Shade tolerant trees will be present in the regeneration. Spring ephemeral wildflowers will be prolific in places.

Pathway 1.1A
Community 1.1 to 1.2

Time (typically >100 years) with little or no large-scale disturbance will favor shade tolerant, late successional species including sugar maple, red maple and American beech.

Pathway 1.2A
Community 1.2 to 1.1

Establishment of advanced oak regeneration (natural or planted) is critical to recruiting oak back into the overstory. If that is desirable, a combination of natural and managed steps will likely be required to favor oak. Depending on the residual stand, management recommendations might include timber stand improvement, mechanical or chemical treatment of unwanted species, and prescribed fire. Consultation with a professional forester is recommended prior to implementation of any management practice, especially the use of prescribed fire. Arthur et al. (2012) discusses conditions when fire should and should not be used in oak management.