Crooked Run Valley
northern red oak (Quercus rubra)
northern red oak
common red oak
eastern red oak
mountain red oak
Quercus borealis Michx. f.
Quercus borealis Michx. f. var. maxima (Marsh.) Sarg.
Quercus maxima (Marsh.) Ashe
CONFIRMATION STATUS: Confirmed.
TAXONOMY: Northern red oak is a member of the red oak-black oak
subgenus (Erythrobalanus) within the order Fagales. The currently
accepted scientific name of northern red oak is Quercus rubra L. The
epithet Quercus rubra was formerly applied to several species of oak includ-
ing the southern red oak (Quercus falcata). Some later taxonomists rejected
the appellation Quercus rubra because of past ambiguity and in 1915 identi-
fied northern red oak as Quercus borealis. In 1950, the name Quercus rubra
was restored. Most current authorities prefer the epithet Quercus rubra,
although Quercus borealis is still occasionally encountered in the literature.
The following varieties are commonly recognized: 1) Quercus rubra var.
borealis (Michx. f.) Farw. and 2) Quercus rubra var. rubra.
Northern red oak hybridizes with many oaks including scarlet oak
(Quercus coccinea), shingle oak (Quercus imbricata), swamp oak
(Quercus palustris), willow oak (Quercus phellos), scrub oak (Quercus
ilicifolia), northern pin oak (Quercus ellipsoidalis), black oak (Quercus
velutina), blackjack oak (Quercus marilandica) and Shumard oak (Quercus
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS: Northern red oak
is a medium to large, variable deciduous tree. It is the tallest and most
rapidly growing of the oaks and commonly reaches 65 to 98 feet (20-30 m)
in height and 2 to 3 feet (61-91 m) in diameter. On extremely favorable
sites plants may grow to 160 feet (49 m) and up to 8 feet (2.4 m) in
diameter. Trees are tall, straight, and columnar with a large crown in
forested stands but are characterized by a short bole and spreading crown
in openings . Plants generally have a strongly developed taproot and a
network of deep, spreading laterals. The gray to grayish-brown bark has
shallow vertical furrows and low ridges and becomes checkered with age.
Northern red oak is monoecious. The acorns are approximately 0.8 to 1.3
inch (20-33 mm) in length, with a shallow, saucer-shaped cup. Acorns are
borne singly or in clusters of two to five. The nut contains a large, white,
bitter kernel. The variety borealis is characterized by smaller acorn cups.
REGENERATION PROCESSES: Northern red oak generally first
bears fruit at 25 years of age, although most trees do not produce acorns in
abundance until 50 years of age. On extremely favorable sites trees as
young as 10 years may bear some fruit. Northern red oak produces good
crops every 2 to 5 years. Yields vary by individual as well as with weather
conditions and site factors. Relatively large, dominant or codominant
individuals with open crowns typically produce more acorns than do trees
with small, restricted crowns. Trees with a 16 inch (41 cm) d.b.h. can yield
800 acorns per year, and trees with a d.b.h. of 20 to 22 inches (51-56 cm)
can yield 1,600 acorns per year. Larger trees tended to be less productive.
Total acorn production may range from 100 to more than 4,100 per tree.
Cold, rainy weather during flowering can result in poor seed production.
Under carefully controlled conditions, acorns can be stored for up to 2 or 3
years. After 52 months in storage, only a few acorns remained viable. In
good acorn years up to 80 percent of the crop is commonly destroyed, and
in poor years virtually the entire acorn crop can be eliminated by birds,
mammals, and insects.
Acorns of northern red oak are characterized by variable dormancy which
requires stratification for germination. Dormancy varies by the individual
seed, but northern seeds often require longer stratification. Under natural
conditions, acorns generally germinate in the spring after dormancy is
broken by over-wintering. Delayed germination may occur but is very rare.
Seeds can be stratified at 35 to 41 degrees F (2-5 degrees C) for several
months. Acorns germinate best in soil which is covered by a layer of leaf
litter. In one study, 80 percent of all planted acorns germinated compared
with less than 1 percent of acorns left on the soil surface. Domestic animals
such as pigs and cows may promote germination by trampling the soil and
"planting" the acorns, and by reducing competing herbaceous vegetation.
Seeds on the soil surface are particularly vulnerable to rodent predation.
In an Iowa study all seeds present on top of the litter layer were destroyed
by rodents compared with 68 percent of buried seeds.
Seeds of northern red oak are primarily dispersed by birds and mammals.
Scatter-hoarders such as the gray squirrel are particularly important
dispersal agents in some areas. Gray squirrels bury as much as 19 percent
of the available acorn crop and fail to recover many seeds over the winter.
Scatter-hoarders typically disperse seed a few yards from the source tree.
Mice and chipmunks are short-distance dispersers and usually move seeds
33 to 98 feet (10-30 m). Blue jays are effective long-distance dispersal
agents and can transport seed from several hundred yards to 2 or 3 miles
(4-5 km). Evidence suggests that blue jays prefer to cache acorns on open
sites or at forest margins. Gravity may aid in seed dispersal.
Seedling establishment is generally limited to years of abundant acorn
production. However, advance regeneration is usually present. In mature
stands, seedlings may number up to 7,000 per acre (2,824/ha), but few
survive more than a few years or grow to more than 6 or 8 inches (15-20
cm) in height. Seedlings require adequate soil moisture for survival and
good early development. Early growth may be reduced by a combination
of shade, low soil fertility, and competing herbaceous vegetation. Shading
alone has little effect on initial seedling establishment.
Northern red oak commonly sprouts vigorously after plants are damaged
or killed by fire or mechanical injury. Small poles, saplings, and even
seedlings can sprout if cut or burned. Although young oaks typically
stump sprout more readily than do older or larger individuals, northern
red oaks up to 22 inches (56 cm) in diameter have produced sprouts.
Stump sprouts derived from larger stems tend to grow faster than those
derived from smaller, damaged stems. Individuals 20 to 25 years of age
regardless of size produce an average of four or five sprouts. Repeated
sprouting is common in northern red oak; many seedlings die back to the
ground level periodically. Seedlings often develop an "s"-shaped curve at
ground level which helps protect dormant buds from fire. Cycles of dying
back and sprouting can result in crooked, flat-topped, or forked stems. Root
sprouting also occurs. Sprouts that develop at or below the ground level are
less likely to decay than are sprouts that develop relatively high on the
parent stump. Sprouting is reduced by low light levels and decreases as
the stand ages. The number of sprout groups decreases from poor to good
sites. Initial sprout growth is typically rapid.
SITE CHARACTERISTICS: Northern red oak grows on a variety of
dry- mesic to mesic sites. It occurs in rich, mesic woods, on sandy plains,
rock outcrops, stable interdunes, and at the outer edges of floodplains.
Northern red oak is most common on north- and east-facing slopes. It
typically grows on lower and middle slopes, in coves, ravines, and on valley
Overstory associates of northern red oak are numerous and include white
oak (Quercus alba), black oak, scarlet oak, southern red oak, post oak
(Quercus stellata), eastern white pine (Pinus strobus), American beech
(Fagus grandifolia), sugar maple, red maple (Acer rubrum), black cherry
(Prunus serotina), American basswood (Tilia americana), sweet gum
(Liquidambar styraciflua), white ash (Fraxinus americana), green ash
(Fraxinus pennsylvanica), aspen (Populus tremuloides), hickories (Carya
spp.), black gum (Nyssa sylvatica), black walnut (Juglans nigra), jack pine
(Pinus banksiana), eastern hemlock (Tsuga canadensis), and elm (Ulmus
spp.). Flowering dogwood (Cornus florida), holly (Ilex spp.), eastern hop-
hornbeam (Ostrya virginiana), sassafras (Sassafras albidum), American
bladdernut (Staphylea trifolia), redbud (Cercis canadensis), persimmon
(Diospyros virginiana), and serviceberry (Amelanchier spp.) are frequent
small tree associates. Common understory shrubs and vines include green-
brier (Smilax spp.), blueberries (Vaccinium spp.), mountain-laurel (Kalmia
spp.), leatherwood (Dirca palustris), witch-hazel (Hamamelis virginiana),
beaked hazel (Corylus cornuta), spice bush (Lindera benzoin), poison-ivy
(Toxicodendron radicans), grape (Vitis spp.), and rosebay rhododendron
(Rhododendron maximum). Numerous herbaceous species occur with
northern red oak.
Annual precipitation averages 30 inches (76 cm) at the northwestern edge
of northern red oak's range and 80 inches (203 cm) in the southern
Appalachians. Mean annual temperatures range from 40 degrees F
(4 deg C) in the North to 60 degrees F (16 deg C) in the South. Growing
season length varies from 100 to 220 days. Northern red oak reaches its
best development in the Ohio Valley and along the west slope of the
Allegheny Mountains where precipitation averages 40 inches (102 cm)
annually and average annual temperature is 52 degrees F (11 degrees C).
Northern red oak grows on clay, loam, and sandy or gravelly soils. Soils
may be deep and free of rocks, or shallow and rocky. Plants generally
exhibit best growth on deep, fertile, well-drained, finely textured soils
with a relatively high water table. Soils are derived from a variety of
parent materials including glacial outwash, sandstone, shale, limestone,
gneiss, schist, or granite.
Northern red oak grows at relatively low elevations in the Smoky
Mountains. The variety rubra typically grows at lower elevations
than does the variety borealis.
SUCCESSIONAL STATUS: Northern red oak is intermediate in shade
tolerance. It is generally considered a midseral species, but its successional
status is poorly known. It has been described as "neither an aggressive
colonizer that is characteristic of early successional species nor an enduring
shade-tolerant, slow-grower . . . typical of late successional species." Even-
aged stands are common; northern red oak is unable to establish beneath
its own canopy. Advanced regeneration provides a mode by which northern
red oak can reoccupy a site following disturbances such as fire, wind damage,
or herbivory. In most areas, advanced regeneration persists for no more
than a few years. Some seedlings have persisted for approximately 25
years despite repeated die-backs. These seedlings did not reach sapling
or pole size unless gaps were created in the forest canopy; most ultimately
died. Northern red oak is often replaced by more shade-tolerant species
such as sugar maple and American basswood. In New England, logging and
slash fires in the late 1800's and early 1900's replaced pine-hemlock forests
with stands made up of oak and maple. In central New England, where
advance regeneration is present prior to disturbance, northern red oak
often assumes dominance between 10 to 40 years after disturbance and
often persists for 100 years or more. Forests are often replaced by sugar
maple, red maple, or gray birch (Betula populifolia).
SEASONAL DEVELOPMENT: The timing of annual budbreak varies
with the genetic composition of the plant and with site characteristics such
as elevation and soils. Budbreak tends to be delayed at higher elevations
and on sites with copper, lead, or zinc mineralized soil. Plants often undergo
relatively rapid vegetative growth from May through June. Episodic or
recurrent shoot growth, in which periods of shoot elongation alternate with
resting periods, can occur throughout the growing season. Growth of leaves
and roots is also often cyclic. However, under natural conditions, seedlings
typically produce a single flush of leaves during a relatively short period of
growth which often lasts only 2 to 3 weeks. The shoot becomes dormant
during early summer despite seemingly favorable growing conditions.
Flowering occurs in April or May, during or before leaf development.
Acorns require two seasons for development and ripen in September
GENERAL DISTRIBUTION: Northern red oak is widely distributed
throughout much of the eastern United States and southeastern Canada.
It grows from Quebec, Ontario, Nova Scotia, and New Brunswick southward
to southwestern Georgia and Alabama. Northern red oak extends westward
through Minnesota and Iowa, south through eastern Nebraska and Kansas
to eastern Oklahoma. It occurs locally in eastern and southwestern
Louisiana and western Mississippi. The variety rubra grows in Georgia and
Alabama, northward through Kentucky, Tennessee, and West Virginia to
New England The variety borealis occurs farther north than variety
rubra does. Variety borealis occurs in Virginia, Tennessee, and North
Carolina in the South and extends northward throughout New England
SKY MEADOWS DISTRIBUTION:
Tree specimens can be found on trails marked in red.
Appalachian Trail/Old Trail
South Ridge/North Ridge
Rolling Meadows/ Lost Mountain
HABITAT TYPES AND PLANT COMMUNITIES: Northern red oak
occurs as a dominant in many communities, including mixed mesophytic
forests, pine-oak communities, and southern bottomland forests.
IMPORTANCE AND USES: The white-footed mouse, eastern
chipmunk, fox squirrel, gray squirrel, red squirrel, white-tailed deer,
flying squirrels, and deer mice consume northern red oak acorns. In a
New Hampshire feeding trial, northern red oak acorns made up 5 to 55
percent (composition dry matter) of deer diets. Acorns of the northern
red oak are a preferred fall and winter food of the gray squirrel. Domestic
hogs also eat large quantities of northern red oak acorns where available.
Acorns are an important fall food source for the black bear. The abundance
of fall mast crops can affect black bear reproductive success during the
Acorns of the northern red oak are an important food source the bobwhite,
red-headed woodpecker, red-bellied woodpecker, blue jay, tufted titmouse,
grackle, white-breasted nuthatch, sapsuckers, quail, ruffed grouse, and
other birds. They represent a particularly important food source for the
wild turkey. A single turkey can consume more than 221 acorns at a
"single meal". Other birds that feed on acorns include the ruffed grouse,
sharp-tailed grouse, ring-necked pheasant, wild turkey, eastern crow,
northern flicker, grackle, blue jay, brown thrasher, tufted titmouse,
starling, lesser prairie chicken, chickadees, nuthatches, and other song-
birds. Acorns are also important food sources for various waterfowl
such as the golden-eye, gadwall, wood duck, hooded merganser, mallard,
American pintail, black duck, redhead, and green-winged teal. Sprouted
acorns are readily eaten by deer, mice, and the northern bobwhite.
White-tailed deer commonly browse leaves and young seedlings. One
researcher reported that deer browsed only 2.8 percent of northern red
oak in Nova Scotia and New Brunswick. However, in feeding trials in New
Hampshire, northern red oak leaves comprised 15 to 30 percent dry
matter of deer diets. Elk, hares, cottontail rabbits, and moose also feed
on northern red oak browse. Pocket gophers occasionally feed on the
roots of seedlings.
Acorns of the northern red oak are highly palatable to many birds and
mammals. Northern red oak acorns appear to be less palatable to the
white-footed mouse than are white oak acorns. Studies indicate that
relatively high tannin levels may impart a bitter taste and decrease
palatability as compared with acorns from other species of oak. However,
gray squirrels prefer northern red oak acorns to the acorns of other oaks.
The palatability of oak browse is reported to be relatively high for domestic
livestock and for many wildlife species. Eastern oaks are preferred by
white-tailed deer in some locations. New growth is particularly palatable
to deer and rabbits.
Northern red oak provides good cover for a wide variety of birds and
mammals. Young oaks with low branches serve as particularly good
winter cover. Oak leaves often persist longer than those of many of
its plant associates and in some areas, young oaks may represent the
only brushy winter cover in dense pole stands. Oaks frequently serve
as perching or nesting sites for various songbirds. Many cavity nesters,
such as the red-bellied and hairy woodpecker, utilize northern red oak.
The well-developed crowns of oaks provide shelter and hiding cover for
tree squirrels and other small mammals. Many birds and mammals use
twigs and leaves as nesting materials. Large oaks provide denning sites
for a variety of mammals.
Northern red oak is well adapted to some types of moderately unproductive
environments, including certain acidic sites, and can be used in various
rehabilitation projects. Northern red oak has been successfully planted
onto coal mine spoils in Ohio, Indiana, Illinois, Kentucky, and Pennsylvania.
Northern red oak is an important source of hardwood lumber. Its wood is
heavy, hard, strong, coarse-grained, and at least moderately durable.
When properly dried and treated, oak wood glues well, machines very
well, and accepts a variety of finishes. The wood of northern red oak has
been used to make railroad ties, fenceposts, veneer, furniture, cabinets,
paneling, flooring, caskets, and pulpwood. Northern red oak has a high fuel
value and is an excellent firewood.
The acorns of many species of oak (Quercus spp.) were traditionally an
important food source for Native American peoples. Acorns of red oak
were leached with ashes to remove bitter tannins and then used in various
foods by many Native American peoples. Preparations made from the bark
were used to treat bowel problems.
Northern red oak was first cultivated in 1724 and is a popular ornamental
shade tree in eastern North America and in parts of Europe.