Northeastern Dry Oak Forest

These oak-dominated forests are one of the matrix forest systems in the northeastern and north-central U.S. Occurring in dry-mesic settings, they are typically closed-canopy forests, though there may be areas of patchy-canopy woodlands. They cover large expanses at low to mid elevations, where the topography is flat to gently rolling, occasionally steep. Soils are mostly acidic and relatively infertile but not strongly xeric. Local areas of calcareous bedrock, or colluvial pockets, may support forests typical of richer soils. Oak species characteristic of dry-mesic conditions (e.g., Quercus rubra, Quercus alba, Quercus velutina, and Quercus coccinea) and Carya spp. (particularly Carya tomentosa, Carya glabra, Carya ovalis, Carya ovata, and Carya pallida) are dominant in mature stands. Quercus montana may be present but is generally less important than the other oak species. Castanea dentata was a prominent tree before chestnut blight eradicated it as a canopy constituent. Acer rubrum, Betula lenta, and Betula alleghaniensis may be common associates; Acer saccharum is occasional. With a long history of human habitation, many of the forests are early- to mid-successional, where Pinus strobus, Pinus virginiana, or Liriodendron tulipifera may be dominant or codominant. Within these forests, hillslope pockets with impeded drainage may support small isolated wetlands, including non-forested seeps or forested wetlands with Acer rubrum, Quercus bicolor, or Nyssa sylvatica characteristic.

Mature stands are dominated by oak species characteristic of dry-mesic conditions (e.g., Quercus rubra, Quercus alba, Quercus velutina, and Quercus coccinea), along with various Carya spp. (particularly Carya tomentosa (= Carya alba), Carya glabra, Carya ovalis, Carya ovata, and Carya pallida). In addition, Quercus montana (= Quercus prinus) may be present but is generally less important than the other oak species. Castanea dentata was a prominent tree before chestnut blight eradicated it as a canopy constituent. Acer rubrum and Betula lenta are frequently common associates. Local areas of calcareous bedrock may support forests typical of richer soils (e.g., with Acer saccharum and/or Quercus muehlenbergii). Common shrubs include Viburnum acerifolium, Hamamelis virginiana, Corylus spp., and Smilax spp., as well as heaths such as Kalmia latifolia, Vaccinium spp., and Gaylussacia spp. Herbs, forbs, and ferns are usually sparse to moderate in density.

These oak-dominated forests are one of the matrix forest systems in the northeastern and north-central U.S. Occurring in dry-mesic settings, they are typically closed-canopy forests, though there may be areas of patchy-canopy woodlands. They cover large expanses at low to mid elevations, where the topography is flat to gently rolling, occasionally steep. The typical landscape position is midslope to toeslope, transitioning to more xeric systems on the upper slopes and ridges. Soils are acidic and relatively infertile but not strongly xeric.

This system is naturally dominated by stable, uneven-aged forests, with canopy dynamics dominated by gap-phase regeneration. Most oaks are long-lived, with typical age of mortality ranging from 200 to 400 years. Quercus coccinea and Quercus velutina are shorter-lived with typical ages being approximately 50 to 100 years, while Quercus alba can live as long as 600 years. Extreme wind or ice storms occasionally create larger canopy openings.

This forest system is characterized by low-severity surface fires that cause variable structure and composition based on fire frequency and intensity. The great majority of historical fires were generated by Native Americans.

Open woodlands developed within a moderate burning regime, (fire-return intervals of 5 to 15 years), and canopy closure occurred with greater fire-return intervals. Shade-tolerant, fire-sensitive trees such as Acer saccharum regenerated beneath oak-hickory canopies when fire was excluded over several decades. With continued fire exclusion, Acer saccharum and other late-successional species gradually replaced overstory oaks and hickories as forest gaps closed (Sutherland et al. 2003), generating a mosaic of vegetation types formed with varying fire history (Cutter and Guyette 1994). A recent study on fire history of a Quercus rubra stand in West Virginia revealed that fire intervals ranged from 7 to 32 years from 1846 to 2002, in contrast to intervals of 7 to 15 years prior to the fire control era. These results were consistent with previous research in the oak forests of Ohio, Maryland, and Missouri (Schuler and McClain 2003).

This system is found from southern New York west through Ohio and Pennsylvania and south to Virginia. It does not extend to the southernmost part of Virginia, except in the Ridge and Valley.