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Quercus velutina, theeastern black oakor more commonly known as simplyblack oak, is a species in thered oak(Quercussect.Lobatae) group ofoaks. It is widespread in eastern and central North America, found in all the coastal states fromMainetoTexas, inland as far asMichigan,Ontario,Minnesota,Nebraska,Kansas,Oklahoma, and easternTexas.[3]
Quercus velutinawas previously known as yellow oak due to the yellow pigment in its inner bark, however nowadays this name is usually reserved forchinkapin oak.[4]It is a close relative of theCalifornia black oak(Quercus kelloggii) found in western North America.
In the northern part of its range, black oak is a relatively small tree, reaching a height of 20–25m (66–82ft) and a diameter of 90cm (35in), but it grows larger in the south and center of its range, where heights of up to 42m (138ft) are known. Black oak is well known to readily hybridize with other members of thered oak(Quercussect.Lobatae) group of oaks being one parent in at least a dozen different named hybrids.[5]
Theleavesof the black oak are alternately arranged on the twig and are 10–20cm (4–8in) long with 5–7 bristle-tipped lobes separated by deep U-shaped notches. The upper surface of the leaf is a shiny deep green, the lower is yellowish-brown. There are also stellate hairs on the underside of the leaf that grow in clumps.[5]
The innerbarkof the black oak contains a yellow pigment calledquercitron, which was sold commercially in Europe until the 1940s.
Key Characteristics:
Sun leaves have very deep u-shaped sinuses.[5]
The buds are velvety and covered in white hair.[5]
Thefruitsoracornsof the black oak are medium-sized and broadly rounded.[6]The cap is large and covers almost half of the nut.[5]
In southern New England, black oak grows on cool, moist soils. Elsewhere it occurs on warm, moist soils.
The most widespread soils on which black oak grows are the Udalfs and Udolls. These soils are derived from glacial materials, sandstones, shales, and limestone and range from heavy clays to loamy sands with some having a high content of rock or chert fragments. Black oak grows best on well drained, silty clay to loam soils.
Black oak grows on all aspects and slope positions. It grows best in coves and on middle and lower slopes with northerly and easterly aspects. It is found at elevations up to 1,200m (3,900ft) in the southern Appalachians.
The most important factors determining site quality for black oak are the thickness and texture of the A horizon, texture of the B horizon, aspect, and slope position. Other factors may be important in localized areas. For example, in northwestern West Virginia increasing precipitation to 1,120mm (44in) resulted in increased site quality; more than 1,120mm (44in) had no further effect. In southern Indiana, decreasing site quality was associated with increasing slope steepness.
Near the limits of black oak's range, topographic factors may restrict its distribution. At the western limits black oak is often found only on north and east aspects where moisture conditions are most favorable. In southern Minnesota and Wisconsin it is usually found only on ridge tops and the lower two-thirds of south- and west-facing slopes.
Black oak is often a predominant species in the canopy of anoak–heath forest.[7][8]
Black Oak is the forest cover type that designates pure stands of the species or those in which it makes up more than 50 percent of the stand basal area. Black oak is a major associate inwhite oak–black oak–northern red oak.
Other tree associates of black oak include pignut hickory (Carya glabra),mockernut hickory(C.tomentosa),bitternut hickory(C.cordiformis), andshagbark hickory(C.ovata); American elm (Ulmus americana) andslippery elm(U.rubra); white ash (Fraxinus americana); black walnut (Juglans nigra) andbutternut(J.cinerea); scarlet oak (Quercus coccinea),southern red oak(Q.falcata), andchinkapin oak(Q.muehlenbergii); red maple (Acer rubrum) andsugar maple(A.saccharum); black cherry (Prunus serotina); and blackgum (Nyssa sylvatica).
Common small tree associates of black oak include flowering dogwood (Cornus florida), sourwood (Oxydendrum arboreum), sassafras (Sassafras albidum), eastern hophornbeam (Ostrya virginiana), redbud (Cercis canadensis), pawpaw (Asimina triloba), downy serviceberry (Amelanchier arborea), and American bladdernut (Staphylea trifolia). Common shrubs includeVacciniumspp., mountain-laurel (Kalmia latifolia), witch-hazel (Hamamelis virginiana), beaked hazel (Corylus cornuta), spicebush (Lindera benzoin),sumac(Rhusspp.), andViburnumspp. The most common vines are greenbrier (Smilaxspp.), grape (Vitisspp.), poison-ivy (Toxicodendron radicans), and Virginia creeper (Parthenocissus quinquefolia).
Black oak ismonoecious. Thestaminateflowers develop from leaf axils of the previous year and thecatkinsemerge before or at the same time as the current leaves in April or May. Thepistillateflowers are borne in theaxilsof the current year's leaves and may be solitary or occur in two- to many-flowered spikes. The fruit, anacornthat occurs singly or in clusters of two to five, is about one-third enclosed in a scaly cup and matures in 2 years. Black oak acorns are brown when mature and ripen from late August to late October, depending on geographic location.
In forest stands, black oak begins to produce seeds at about age 20 and reaches optimum production at 40 to 75 years. It is a consistent seed producer with good crops of acorns every 2 to 3 years. In Missouri, the average number of mature acorns per tree was generally higher than for other oaks over a 5-year period, but the number of acorns differed greatly from year to year and from tree to tree within the same stand.
The number of seeds that become available for regenerating black oak may be low even in good seed years. Insects, squirrels, deer, turkey, small rodents, and birds consume many acorns. They can eat or damage a high percentage of the acorn crop in most years and essentially all of it in poor seed years.
Black oak acorns from a single tree are dispersed over a limited area by squirrels, mice, and gravity. The blue jay may disperse over longer distances.