BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Carya ovata | Shagbark Hickory 



GENERAL BOTANICAL CHARACTERISTICS : 
Shagbark hickory is a medium to large deciduous tree which commonly
grows to 60 or 80 feet (20-25 m) in height and up 20 inches (51 cm) in
diameter [21,29].  On favorable sites, trees may grow to 131 feet (40 m)
or more in height and reach up to 9 feet 8 inches (295 cm) in diameter
[57].  Open-grown plants are characterized by an oblong crown, whereas
those growing in forested areas tend to have a straight, slender
columnar crown [29].  The shaggy gray bark exfoliates in long platelike
strips [2,24,57].  Shagbark hickory has a deep taproot [29].

Shagbark hickory is monoecious [54].  Staminate flowers are borne on
long-stalked catkins at the tip of old wood or in the axils of the
previous season's leaves [23,24,54].  Pistillate flowers occur in short
terminal spikes [23,54].  The fruit is a smooth, globose or subglobose
nut [46].  Nuts are borne singly or in clusters of two or three [24].


RAUNKIAER LIFE FORM : 
   Undisturbed State:  Phanerophyte (megaphanerophyte)
   Undisturbed State:  Phanerophyte (mesophanerophyte)
   Burned or Clipped State:  Chamaephyte
   Burned or Clipped State:  Hemicryptophyte
   Burned or Clipped State:  Cryptophyte (geophyte)


REGENERATION PROCESSES : 
Shagbark hickory regenrates through seed and by vegettaive means.

Seed:  Shagbark hickory begins producing seed at approximately 40 years
of age.  Optimum seed production occurs between 60 and 200 years of age;
maximum age of seed production is approximately 300 years [57].  Good
crops occur at 1- to 3-year intervals, with little or no seed production
in intervening years [23].  During favorable years, some trees can
produce 1.5 to 2 bushels (53-70 L) of nuts [7].  Tree (stem) diameter
and crown size apparently serve as the best indicators of seed
production [23].  Seed is dispersed by gravity and by birds and mammals
[23,61].  Squirrels and chipmunks are typically much more important as
dispersal agents than birds are.  The now-extinct passenger pigeon
dispersed seeds of many species of hickory [61].  During poor seed
years, seed predation by birds, mammals, and insects can eliminate most
of the seed crop [23].

Hickory seeds exhibit embryo dormancy that can be broken by
stratification at 37 degrees F (3 deg C) for 90 to 120 days [23].
Germination of fresh seed ranges from 50 to 75 percent.

Vegetative regeneration:  Shagbark hickory typically sprouts
prolifically after plants are cut or damaged by fire [23].  Trees with
diameters up to 8 to 10 inches (20-24 cm) typically sprout from the
stump.  As diameter increases stump-sprouting declines, but
"root-suckering" increases.  Young sprouts generally compete well in
newly regenerated stands, but after 10 to 20 years, the rate of sprout
growth declines and shagbark hickory may be outcompeted by faster
growing associates [23].


SITE CHARACTERISTICS : 
Shagbark hickory is most commonly associated with upland slopes in the
North, and with river bottoms and coves in the South [23].  It also
grows on the lower slopes of wooded bluffs, in ravines, valleys, and at
the edges of swamps [21,29].  Shagbark hickory generally occurs as
scattered individuals or in small groups but rarely forms pure stands
[2,51].

Plant associates:  Shagbark hickory occurs as a principal dominant in
drier parts of the upper Midwest with oaks (Quercus spp.) and other
hickories. [59].  It also grows as aminor component in bur oak (Q.
macrocarpa), chestnut osk (Q. prinus), white oak (Q. alba)-black
oak-northern red oak, pine (Pinus spp.)-oak-sweetgum (Liquidambar
styraciflua),loblolly pine (Pinus taeda)-hardwood, and swamp chestnut
oak (Quercus prinoides)-cherrybark oak (Q. falcata var. pagodaefolia)
[23].  Many oaks, including white oak, northern red oak, black oak,
northern pin oak (Quercus ellipsoidalis), southern red oak (Q. falcata),
chinkapin oak (Q. muehlenbergii), bur oak, and other hickories are
generally prominent overstory associates [1,23,59].  Red maple (Acer
rubrum), sugar maple (A. saccharum), hophornbeam (Ostrya virginiana),
shortleaf pine (Pinus echinata), American basswood (Tilia americana),
redbud (Cercis canadensis), and sourgum (Nyssa sylvatica) also commonly
occur with shagbark hickory [2,48].

Understory associates are numerous and varied throughout the species'
range.  Raspberries and blackberries (Rubus spp.), blueberries and
huckleberries (Vaccinium spp.), rhododendron (Rhododendron spp.),
serviceberry (Amelanchier spp.), gooseberries (Ribes spp.), hawthorn
(Crataegus spp.), hazel (Corylus cornuta), muscadine grape (Vitis
rotundifolia), common greenbrier (Smilax rotundifolia), western
snowberry (Symphoricarpos occidentalis), common witch-hazel (Hamamelis
virginiana), wild ginger (Asarum caudatum), nettle (Urtica spp.), and
Canada beadruby (Maianthemum canadense) are important understory
components in many areas [2,3,9].

Climate:  Shagbark hickory grows across a wide range of climatic
conditions but grows best in a humid climate.  It can survive
temperature extremes of -40 degrees F (-40 deg C) and 115 degrees F (46
deg C).  Growing season length varies from 140 days in the North to 260
days in the South [23].

Soils:  Shagbark hickory reaches greatest abundance on deep, rich, moist
soils [29,42].  It occurs on soils derived from a variety of sedimentary
and metamorphic parent materials and grows across a wide range of soil
fertility conditions [23].  It appears to be tolerant of soils with high
concentrations of lead and zinc [6].  In Arkansas, it is common on
clayey soils derived from Mississippian and Pennsylvanian shales [23].

Elevation:  Shagbark hickory generally occurs at high elevations in much
of the North [42].  It typically occurs below 3,000 feet (910 m) in the
foothills of West Virginia [15].  In the Blue Ridge Mountains of North
and South Carolina, it occurs up to 3,000 feet (910 m) and in northern
Arkansas at elevtions below 2,000 feet (610 m) [23].


SUCCESSIONAL STATUS : 
Shagbark hickory is slow growing and intermediate in shade tolerance.
Saplings can persist for many years beneath a forest canopy and respond
rapidly when released.  It grows as a climax species in most oak-hickory
forests [23].  It is a prominenent late seral or climax species in
old-growth oak stands in Indiana where it replaces early to mid seral
species such as honey locust (Gleditsia triacanthos), black walnut
(Juglans nigra), and oak [45].  It replaces bur oak, black cherry
(Prunus serotina), and white oak in bur oak-chinkapin oak-black oak
forests of Wisconsin and northeastern Kansas [1,16].  It may ultimately
be replaced by more shade-toleant species such as sugar maple, American
basswood, and hophornbeam [1,16].

At the western edge of its range, shagbark hickory has invaded the
prairie [32], but heavy-seeded species such as shagbark hickory are
generally slow to invade new areas [22].  Shagbark hickory has invaded
oldfield communities, but seedlings are rarely observed more than 100
feet (30 m) from the forest margin [11].  In parts of east-central
Indiana and elsewhere, it often establishes in gaps created by dead elms
(Ulmus spp.) [44].


SEASONAL DEVELOPMENT : 
Shagbark hickory flowers in late March at the southwestern edge of its
range and as late as early June in the North and Northeast [23].
Flowers open when the leaves are nearly full grown [23].  Fruit ripens
in September and October and splits into four pieces [34].  Seed is
dispersed from September thrugh December.  Generalized flowering and
fruiting dates by geographic location are:

Location        Flowering          Fruiting       Authority

New England     May 29-June 28     ----           Seymour 1985
n-c Plains      April-May          Sept.-Oct.     Stephens 1973
Great Plains    April-May          ----           Great Plains
                                                  Flora Assoc. 1986
se U.S.         May                ----           Duncan & Duncan 1988
sw U.S.         March-June         Sept.-Cot.     Vines 1960
NC, SC          May                October        Radford & others 1968

Related categories for Species: Carya ovata | Shagbark Hickory