Crooked Run Valley
pin oak (Quercus palustris)
swamp Spanish oak
SCIENTIFIC SYNONYMS: None.
CONFIRMATION STATUS: Confirmed.
TAXONOMY: The currently accepted scientific name of pin oak is
Quercus palustris Muenchh. It has been placed within the subgenus
Erythrobalanus, or red (black) oak group. There are no recognized
varieties, subspecies, or forms. Pin oak hybridizes with the following
species: scarlet oak, shingle oak, willow oak, northern red oak, Shumard
oak and black oak.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS: Pin oak is a fast-
growing, native, deciduous, monoecious tree. It is physiologically mature
at 80 to 100 years. Little is known of its maximum age, but one old growth
stand averaged 138 years of age. On good sites, pin oak may reach 120 feet
(37 m) in height and 60 inches (150 cm) in d.b.h. , but the tree is usually 60
to 80 feet (18-24 m) tall at maturity. Acorns are 0.5 inches (1.3 cm) or less
in length, the smallest of the tree oaks. An open-grown pin oak has a well-
defined main trunk through most of the wide, symmetrical crown. The
upper branches are ascending, the middle branches horizontal, and the
lower branches inclined downward to give pin oak a distinctive pyramidal
shape. Lower branches remain alive on open-grown trees. The branches
die in closed stands, but are retained for many years. There are numerous
small stiff branches on the trunk and larger limbs. Seedlings develop a
strong taproot in well-aerated soils. As trees become older, the root system
becomes more fibrous.
REGENERATION PROCESSES: Seed production begins when the tree
is about 20 years old, although open-grown trees may begin producing by
15 years. Poor acorn crops occur in 3- to 4-year intervals. Dissemination is
by animals, primarily squirrels, mice, blue jays, and woodpeckers. Over a
4-week period, blue jays transported and cached 54 percent of the available
pin oak acorn crop from a stand on the campus of Virginia Polytechnic
Institute and State University in Blacksburg. The high percentage may
be skewed, however, because of the high number of consumers per tree
on a campus compared to a forest. The mean transport distance between
seed trees and caches was 0.7 mile (1.1 km), with a range of 0.06 to 1.2
miles (0.1-1.9 km). Pin oak acorns fall within the preferred size range [0.4
to 0.7 inches (1.1-1.7 cm) in diameter] of blue jays. Pin oak acorns require
a 30- to 40-day cold stratification period at 32 to 41 degrees Fahrenheit
(0-5 deg C). Viability is high. Acorns submerged in cold water for as long
as 6 months were not damaged (a thick waxy coating on the pericap
restricts water absorption).
Seedling establishment is often high after a good acorn crop year. Pin oaks
are most likely to establish if the litter layer is 0.5 to 2 inches (1.3-5.1 cm)
deep. Pin oak germination and early establishment can occur under a dense
canopy, but seedlings will die after 2 to 3 years unless they are released. In
a study in southern Illinois, pin oak reproduction was most abundant in
mixed hard-hardwood communities composed of oaks (Quercus spp.) and
hickories (Carya spp.); low in mixed soft-hardwood communities composed
of silver maple (Acer saccharinum), green ash (Fraxinus pennsylvania),
sweetgum, hackberry (Celtis occidentalis), and American sycamore
(Platanus occidentalis); low in eastern cottonwood (Populus deltoides)-
black willow (Salix nigra) communities; low in old fields; and rare in newly
formed land (i.e. exposed sand bars). Pin oak seedlings are classified as
intermediate in tolerance to shallow flooding during the growing season.
Pin oak seedlings and young trees sprout vigorously from the root collar
SITE CHARACTERISTICS: Pin oak occurs primarily on bottomland
sites that usually flood intermittently during the dormant season but not
during the growing season. These sites include clay flats, depressions
where water accumulates in winter, and clay ridges of first bottoms.
Overstory associates include swamp white oak (Quercus bicolor), willow
oak, overcup oak (Quercus lyrata), bur oak (Quercus macrocarpa), Nuttall
oak (Quercus nuttallii), swamp chestnut oak (Quercus michauxii), blackgum
(Nyssa sylvatica), green ash, slippery elm (Ulmus rubra), shellbark hickory
(Carya laciniosa), shagbark hickory (Carya ovata), river birch (Betula
nigra), Ohio buckeye (Aesculus glabra), and American sycamore. Shrubs
and small tree associates include American hornbeam (Carpinus
caroliniana), possumhaw (Ilex decidua), and poison-ivy (Toxidendron
radicans). The herbaceous understory associates include sedges (Carex
spp.), bedstraw (Galium spp.), and skullcap (Scutellaria spp.).
SUCCESSIONAL STATUS: Pin oak is intolerant of shade. It usually
occurs as a dominant or codominant in even-aged stands. Suppressed trees
usually die within a few years. Pin oak occurs primarily in early successional
stages of bottomland forests. During drought or as the surface drainage in
swamps and sloughs improves, pin oak invades and replaces the first
pioneer trees such as black willow, eastern cottonwood, blackgum, swamp
privet (Forestiera acuminata), and buttonbush (Cephalanthus spp.). With
further surface drainage, pin oak communities are succeeded by white oak,
cherrybark oak, red maple, American elm, sweetgum, and hickory.
SEASONAL DEVELOPMENT: Pin oak flowers in the spring about the
same time as the leaves appear. Acorns mature at the end of the second
growing season and are dispersed from September through early December.
GENERAL DISTRIBUTION: Pin oak occurs primarily along major
rivers and on glacial till plains in the north-central and eastern United
States. It is distributed from southwestern New England; west to extreme
southern Ontario, southern Michigan, northern Illinois, and Iowa; south to
Missouri, east Kansas, and northeastern Oklahoma; and east to central
Arkansas, Tennessee, central North Carolina, and Virginia.
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: Pin oak is found
in bottomland hardwood communities. Nearly pure even-aged stands of pin
oak are known as "pin oak flats".
IMPORTANCE AND USES: Pin oak acorns are an important food
for wildlife including white-tailed deer, squirrels, wild turkeys, woodpeckers,
bluejays, and waterfowl. Acorns are an especially important food source for
wood ducks and mallards during fall migration. Bottomland hardwoods that
are seasonally flooded provide nesting sites for colonial waterbirds and
many passerines. Pin oak is an important species in greentree reservoirs
(artificially flooded areas) that attract and provide food for migrating
Pin oak is recommended for graded/top-soiled mine spoils. In southern
Illinois, pin oak seedlings (both planted and direct seeded) had among the
best survival and growth of nine oak species tested on graded cast
overburden covered with about 16 inches (40 cm) of eroded old field
surface soil. Pin oak has naturally established on surface-mined lands in
Missouri, Kansas, and Oklahoma.
Pin oak does not self-prune, so the wood has many small knots which
reduce its quality and utility. The hard, heavy wood is used locally for
construction timbers, mine props, and fuel.
Pin oak is widely planted as a shade tree and ornamental. It transplants
well and tolerates urban stresses such as street salt, acid rain, and smoke.
Black ink can be made from twig galls on pin oak.