Bluejack Oak

Common and often gregarious on the southern slopes of the Himalayas from 1000-2700 m. The wood is used for building purposes and the leaves are used for fodder.

Quercus incana reportedly hybridizes with Q . falcata [= Q . × subintegra (Engelmann) Trelease], Q . hemisphaerica (D. M. Hunt 1989), Q . laurifolia (= Q . × atlantica Ashe), Q . laevis (= Q . × asheana Little), Q . marilandica (= Q . × cravenensis Little), Q . nigra (= Q . × caduca Trelease), and Q . phellos (E. J. Palmer 1948); with Q . pumila (D. M. Hunt 1989); and with Q . velutina (= Q . × podophylla Trelease), and questionably, Q . myrtifolia .

Trees 6-18 m tall. Shoots puberulous to tomentose. Winter buds 1.5-2 cm long, covered with brown scales. Leaves elliptic-lanceolate to ovate-lanceolate, 6-15 x l.7-4.7 cm, coarsely serrate but not at the base, acuminate, penninerved, nerves 11-20 pairs, upper surface dark green, lower white tomentose; petiole 0.4-l.5 cm long. Male flowers in catkins, 6-14 cm long; bract ovate-oblong to oblong-orbiculate, c. 2 mm long; perianth tomentose, segments c. 1 mm long, obtuse or acute; stamens 4-6; anthers c. 1 mm long, hairy, oblong, apiculate. Cupule c. l.2 cm broad, sub-globose, enclosing half the nut at maturity. Nut 1-2 cm long, canescent, umbo tipped, glabrescent.

Trees , deciduous, to 10 m. Bark dark brown to black with square plates. Twigs brown to reddish brown, 1-2.5 mm diam., tomentose to sparsely pubescent. Terminal buds light brown to reddish brown, narrowly ovoid to conic, 3.5-7 mm, distinctly 5-angled in cross section, scales pubescent, often tuft of reddish or silvery hairs at apex. Leaves: petiole 2-8(-10) mm, tomentose. Leaf blade narrowly ovate or elliptic to obovate, usually widest near middle, planar, 30-100 × 12-35 mm, base acute (rarely attenuate) to rounded, margins entire, with 1 apical awn (leaves on juvenile or 2d-flush growth may have 2-3 shallow lobes and 3-5 awns), apex acute or obtuse, rarely rounded; surfaces abaxially densely tomentose, hairs in vein axils often reddish, easily distinguished from others, adaxially often glossy, sparsely pubescent, especially along midrib and near base, veins often raised. Acorns biennial; cup saucer-shaped to bowl-shaped, 4.5-8 mm high × 10-18 mm wide, covering 1/4-1/3(-1/2) nut, outer surface pubescent or puberulent, inner surface uniformly pubescent, scale tips tightly appressed, obtuse or acute; nut ovoid (rarely subglobose) to broadly ellipsoid, 10-17 × 10-16 mm, occasionally striate, glabrate, scar diam. 5.5-10.5 mm.

Ala., Ark., Fla., Ga., La., Miss., N.C., Okla., S.C., Tex., Va.

Distribution: Outer and temperate N.W. Himalayas to Nepal, Upper Burma.

Fl. Per.: April-May. Fr. Per.: August-September.

Flowering spring.

Well-drained sandy soils of barrens, hammocks, dunes, and upland ridges; 0-250m.

Quercus cinerea Michaux

bluejack oak
upland willow oak
sandjack oak
cinnamon oak

More info for the terms: involucre, tree

Bluejack oak is a native, deciduous small tree, usually growing to 35
feet (10.6 m), with a maximum height of about 50 feet (15 m) [11,40].
The crown is open and irregular, the trunk is usually short [15], and
the branches are stout and crooked [40]. On the Coastal Plain of
Florida, bluejack oak roots were concentrated in the top 5 inches (13
cm) of soil; this may have been related to the low fertility of deeper
soil horizons in this habitat. A deep root system is normal for most
oaks [1]. The acorns are 0.4 to 0.72 inch (10-18 mm) broad; the
involucre covers one-half to one-third of the acorn [11].

The national champion bluejack oak was reported from Texas; it measured
51 feet (15.5 m) in height, 7 feet (2.1 m) in circumference, and had a
crown spread of 56 feet (17 m) [15].

Bluejack oak occurs on the Atlantic and Gulf coastal plains from
southeastern Virginia south to central Florida; west to Louisiana and
eastern and central Texas; and north to southeastern Oklahoma and
southwestern Arkansas [22].

More info for the terms: avoidance, climax, codominant, fire frequency, fire intensity, fire regime, fire suppression, frequency, fuel, hardwood, litter, mesic, natural, presence, root crown, surface fire, xeric

Bluejack oak is well adapted to survive fire and may be dependent on
fire to maintain the open conditions that it requires to be competitive.
It occurs in longleaf pine communities which are described as a fire
climax. The natural fire regime of longleaf pine communities is
characterized by frequent low-intensity surface fires [6,27,36]. A
decrease in fire frequency favors scrub oaks over longleaf pine, but
very long fire-free periods are unfavorable to bluejack oak. In the
absence of fire, bluejack oak is outcompeted by taller and more shade
tolerant species such as laurel oak (Quercus laurifolia) and sand live
oak [28,47]. Top-killed or top-damaged bluejack oak sprout from the
root crown following fire [13,27,28,33].

Bluejack oak occurs in highly fire-adapted and fire-dependent
communities on dry sandhills. Where longleaf pine and wiregrass are
dominant, sufficient litter builds up and fires occur frequently,
sometimes annually. The natural interval is thought to be 3 to 10
years. Sufficient fuel to carry surface fire accumulates in about 3 to
4 years [6]. The natural fire regime was maintained or expanded for
thousands of years by human-set fires. In presettlement times Native
Americans burned these communities for a number of purposes, usually at
short intervals. European settlers continued the practice to improve
grazing, remove "rough", and reduce plant diseases and insects. Fire
suppression and fire avoidance (meaning no fires were set) were
practiced in the early parts of this century until the beneficial
effects of fire were recognized and began to be incorporated into
management plans [6,18].

There are a number of hypotheses to explain the presence of bluejack oak
in longleaf pine communities. Garren [13] differentiated between the
typical longleaf pine community, which has no hardwood midstory, and
longleaf pine-scrub oak types. These oaks include turkey oak, blackjack
oak, sand post oak, and bluejack oak. He proposed that scrub oak
reproduction appears in small openings in typical longleaf pine forests,
establishing on soils which are so dry and sandy that other plants grow
poorly and are unable to compete. Annual or frequent fires thin
longleaf pine reproduction and allow an increase in the number of scrub
oak stems through sprouting; continued frequent fire maintains the
presence of these fire-tolerant scrub oaks in the community [13].

Longleaf pine has been slow to reinvade areas from which it was removed;
the fire regime has been altered both by its absence and by fire
suppression [6]. Bluejack oak is codominant with turkey oak or may be
the sole dominant on some former longleaf pine sandhills; it has been
suggested that bluejack oak is less tolerant of extremely xeric
conditions or prefers more fertile soils than does turkey oak [28]. All
three phases of the longleaf pine-scrub oak type are fire maintained
[6,25]. The role of bluejack oak in these communities is determined by
fire and soil moisture regime; where turkey oak and bluejack oak
cooccur and where fire has been excluded for several decades, bluejack
oak abundance declines more rapidly than that of turkey oak [28]. In
Florida, bluejack oak decreased dramatically in importance value between
1951 and 1972 in a longleaf pine-turkey oak stand that had not
experienced fire since 1931. However, on a longleaf pine-bluejack oak
site with a similar fire-free period, bluejack oak importance value
decreased only slightly between 1951 and 1972. The author hypothesized
that bluejack oak will probably continue to decline in the absence of
fire, and mesic hammock species will increase in importance [39].

Bluejack oak is not a typical member of sand pine (Pinus clausa) scrub
communities, which occur on many of the same types of sandhills as
longleaf pine communities. Distribution and composition of sand pine
scrub appears to be related to edaphic conditions [6]. These
communities are also fire maintained and fire-dependent; however, their
fire regime is quite different from that of the longleaf pine
communities. Sand pine scrub communities historically experienced
intense crown fires at intervals of 30 to 60 years [6,27]. The absence
of bluejack oak from these communities may have more to do with the
thick understory of evergreen oaks and/or edaphic conditions than with
fire intensity, but this relationship remains unexplored in the
literature.

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".

More info for the terms: cover, density, seed, succession, top-kill

Prescribed fire could be used to maintain longleaf pine/wiregrass
communities (in which bluejack oak occurs). There is a need to consider
the following factors when planning prescribed fires for these
communities: 1) FIRE REGIMES need to be variable within and among
sites, 2) the sites themselves are variable, 3) ecotones and
transitional communities need to be maintained, and 4) there are species
and communities which were historically dependent on fires originating
within pinelands and flatwoods [27].

Where longleaf pine has been removed, and if there are few or no
longleaf pine seed trees, frequent fire results in a nearly pure scrub
oak type. Heavy logging followed by infrequent fire results in
succession to oak-hickory with or without an intervening scrub oak stage
[13]. Fire may be effective in reducing canopy cover and stature of
bluejack oak but it is not effective in eradicating bluejack oak from a
site [44]. Single prescribed fires have very little effect on bluejack
oak; fires repeated annually are more effective in reducing bluejack oak
cover and density [3]. In South Carolina, a patchy, lightning-caused,
mid-summer fire resulted in significantly reduced growth (the first
growing season following the fire) in all species except bluejack oak
[5]. It has been suggested that timing prescribed fires for periods
when reserves are lowest may decrease oak sprouting potential [44].
Seasonal trends in carbohydrate reserves for bluejack oak have been
reported for western Florida [44]. Other factors being equal, burning
later in the season may increase crown reduction and top-kill. Timing
fires to maximize intensity may be just as important or more important
than phenological stage for maximizing oak reduction. Growing season
fires carry a greater risk of damaging pines, however [3].

More info on this topic.

More info for the term: phanerophyte

Phanerophyte

More info for the term: xeric

Bluejack oak is restricted to well-drained, sandy upland soils,
flatwoods, and river terraces [11,15]. It increases in dominance
downslope of the ridge tops; these downslope areas have finer soils and
better developed underlying clay horizons nearer the surface than do
ridgetop sites. Thus downslope sites are slightly less xeric than the
ridgetops [6,39]. The highest elevation at which bluejack oak occurs is
about 660 feet (200 m) [11].

More info on this topic.

This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

40 Post oak - blackjack oak
70 Longleaf pine
71 Longleaf pine - scrub oak
72 Southern scrub oak
76 Shortleaf pine - oak
83 Longleaf pine - slash pine
84 Slash pine
85 Slash pine - hardwood

More info on this topic.

This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

FRES12 Longleaf - slash pine
FRES14 Oak - pine
FRES15 Oak - hickory

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: forest

K112 Southern mixed forest (seral stages)

More info for the term: hardwood

In southwestern Alabama, a 1976 prescribed, late summer fire in a
longleaf pine stand resulted in only 9 percent complete kill of all oaks
(bluejack oak stems numbered 23 out of a total of 75 oak stems), even
though the fire caused 89 percent defoliation of oaks. A second summer
fire in 1978 resulted in a total of 20 percent complete kill of oaks,
mostly among those stems that had been top-killed in the first fire.
Crown reduction and mortality were strongly associated with diameter;
for all hardwoods, mortality was highest for the 1-inch diameter class.
On a rating scale where 5 indicates no effect and 1 is complete kill,
the average degree of damage sustained by bluejack oak stems (average
1.7 inches [4.3 cm] dbh) from summer fire was rated as 3.9, with an
average crown reduction of 29 percent [3].

In the same study, 1980 spring prescribed fires (3 fires, which were set
at specific phenological stages) resulted in a 47 percent crown
reduction the first year after burning, and a 39 percent crown reduction
(i.e., 8% recovery of crown canopy) after the second growing season.
Only 5 out of 537 hardwood trees were completely killed by these fires.
A second set of spring fires (in 1981) was more effective at causing
hardwood damage, but still completely killed only 12 of 526 trees. The
species most resistant to fire injury were bluejack oak and turkey oak
[3].

More info for the term: cover

Bluejack oak acorns are consumed by fox squirrels, including the rare
Sherman's fox squirrel [29]. The acorns are also consumed by
white-tailed deer, wild turkey, and quail. Bluejack oak is not browsed
by white-tailed deer except in areas where succulent sprouts are
available and where white-tailed deer numbers are high. Oaks, including
bluejack oak, provide brushy cover for birds in longleaf pine
communities which otherwise do not have midstory cover. Ground cover is
sparse under the oaks; birds benefit from having areas of exposed
mineral soil [32].

Sherman's fox squirrel is dependent on the longleaf pine-scrub oak
communities in which bluejack oak occurs. Other rare species that are
associated with these longleaf pine communities include the red-cockaded
woodpecker, a scarab beetle (Ataenius sciurus) which is only found in
Sherman's fox squirrel nests, gopher tortoise, and indigo snake [29,46].

More info for the terms: codominant, cover, forest, herb, natural, phase, tree

Bluejack oak typically occurs in longleaf pine (Pinus palustris)
communities [25,27,36,]. Bluejack oak and turkey oak (Quercus laevis)
grow to about half the height of the dominant longleaf pines,
maintaining a sparse middle canopy layer. The herb layer is usually
dominated by wiregrass (Aristida stricta) [28]. There are three
distinguishable phases of the Florida sandhills (longleaf pine)
associations: 1) turkey oak (Quercus laevis), 2) bluejack oak or sand
post oak (Q. stellata var. margaretta), and 3) southern red oak (Quercus
falcata) [6,7,25,36]. In each of these associations, longleaf pine
occurs as scattered overstory individuals. The turkey oak phase occurs
on the driest sites, with scattered bluejack oak and persimmon
(Diospyros virginiana). The bluejack oak phase is more characteristic
of fine-textured, somewhat more fertile soils. Live oaks (Quercus spp.)
are common in the overstory. The herb layer is characterized by
wiregrass and pineywoods dropseed (Sporobolus junceus) [6]. In the
sandhills of the Big Thicket region of Texas, dominant oaks are bluejack
oak and post oak (Q. stellata); dominant pine species include longleaf
pine, shortleaf pine (P. echinata), and loblolly pine (P. taeda). Pine
densities are low, herb cover is sparse, and there are many areas of
exposed sand [6].

In Texas, bluejack oak is found on the deep sands of Pineywoods, Gulf
prairies and marshes, and post oak savanna (Quercus stellata). In post
oak savanna, associated tree species include blackjack oak (Quercus
marilandica), black hickory (Carya texana), mesquite (Prosopis spp.),
Texas live oak (Q. virginiana var. fusiformis), post oak, and sand post
oak. Associated herb layer species include sand lovegrass (Eragrostis
trichodes) and threeawn (Aristida spp.). In the northeast Pineywoods,
bluejack oak occurs in shortleaf pine-post oak-southern red oak and
longleaf pine-bluejack oak associations. Flowering dogwood (Cornus
florida) is associated with bluejack oak on some sites [45]. Bluejack
oak shares dominance with blackjack oak and sand post oak on sites
downslope of the extremely dry ridge tops that are dominated by turkey
oak [6].

Bluejack oak is listed as a dominant, codominant, or indicator species in
the following publications:

Longleaf pine communities of the west Gulf Coastal Plain [4]
The vegetation of the Apalachicola National Forest: an ecological
perspective [7]
Natural communities of Florida's inland sand ridges [9]
Landscape ecosystem classification for South Carolina [19]
Forest vegetation of the Big Thicket, southeast Texas [23]
Eastern deciduous forest, Vol. 1 [41]

More info for the term: tree

Tree

More info for the terms: fire suppression, hardwood, natural

Longleaf pine communities (in which bluejack oak occurs) are ranked as
threatened by the Texas Natural Heritage Program [46]. The Florida
Natural Areas Inventory has ranked sandhill (longleaf pine) communities
as secure globally but vulnerable at the state level (G4/G3) [29].

The removal of longleaf pine from thousands of acres of sandhills,
coupled with fire suppression, has resulted in the conversion of former
longleaf pine savanna to oak scrub and hardwood hammock communities.
Many of these areas are being converted to other pines, and very few
acres are being managed to retain the typical longleaf pine physiognomy
[27]. There is a need to preserve longleaf pine habitat, in view of its
ecological importance and diminished distribution. Loss of this habitat
is identified as a major cause of population declines of gopher tortoise
and indigo snake [29,42]. Bluejack oak is recommended for inclusion in
longleaf pine stands for its wildlife value [29].

Attempts to reforest former longleaf pine forests with longleaf and
other pines have included clearcutting and burning the scrub oaks and
planting pine seedlings. The oaks are difficult to control because of
their sprouting ability. Herbicides were reported as effective in
reducing bluejack oak, resulting in an increase in pine seedling growth
[24]. In Florida, successful conversion of scrub oaks to slash pine
(Pinus elliottii) using similar site preparation methods has been
reported [16]. In eastern Texas, however, clearcutting and burning or
clearcutting and scalping scrub oak sites on Typic Quartzipsamments
soils has resulted in the virtually complete removal of organic matter
from approximately 6,000 acres (2,400 ha). Several attempts at
reforestation were unsuccessful, largely due to droughty site conditions
and related animal or insect predation on seedlings. In this study
longleaf pine outplanted from containers had the highest survival rate.
Timber production is not recommended as the primary goal for droughty
sands; aesthetics, groundwater protection, and wildlife management
should take a higher priority when developing management plans for such
sites [37].

The ranges of nutritive value of bluejack oak acorns have been reported
as follows [32,34]:

Percent
protein 5.9 - 7.42
fat 12.66-31.77
N-free
extract 40.37-67.06

AL AR FL GA LA MS NC OK SC TX
VA

Bluejack oak acorns were highly preferred by fox squirrels in a study
that included 12 species of oaks [30].

More info on this topic.

Bluejack oak flowers from April to May [11]. The acorns mature in the
fall of their second season. The leaves are sometimes retained until
late into winter, particularly when winter temperatures are mild [15].

More info for the term: top-kill

Bluejack oaks sprout following top-kill by fire; fires usually result in
an increase in the number of bluejack oak stems even when they have
been repeatedly killed back [13,43]. Stems larger than 8 inches dbh
have a greatly reduced ability to sprout after top-kill [43]. In
Florida, prescribed summer fires in oak domes (within longleaf pine
communities) caused stem mortality of bluejack oak. The degree of
mortality was not reported. Bluejack oak sprouted in less than 1 year
following the fire (most of the other species in the dome sprouted in
less than 6 months) [47]. In northern Florida, a 50-year-old slash
pine-longleaf pine stand was subjected to two prescribed winter fires 2
years apart. The overstory pines were unaffected by the fire; canopy
coverage of bluejack oak decreased from 0.9 percent after the first fire
to 0.2 percent after the second fire [26].

Tree with adventitious-bud root crown/soboliferous species root sucker

More info for the terms: basal area, root crown, seed

Bluejack oak reproduces by seed (acorns) [15]. Acorns are first
produced when trees are about 2 inches (5 cm) dbh, with optimum yields
at 4 to 8 inches (9.6-20 cm) dbh. Acorn yields per square foot of basal
area are relatively high. Bluejack oak is a consistent acorn producer
[17]; one study reported that 91 percent of bluejack oaks produced
acorns over a 6-year period [32].

Bluejack oak sprouts vigorously from the root crown when aboveground
stems are damaged or removed. It also forms thickets which are produced
by subterranean runners [15].

More info on this topic.

More info for the term: climax

Facultative Seral Species

Bluejack oak is probably not tolerant of deep shade, although it does
grow under open pine canopies. Monk [25] described bluejack oak as a
successional species: it is characteristically associated with
successional communities and is encountered in climax stands only as
widely scattered individuals. The successional relationships of
bluejack oak are closely controlled by fire and are therefore further
discussed in FIRE ECOLOGY and FIRE EFFECTS.

Quercus cinerea Michx. [22]

The currently accepted scientific name for bluejack oak is Quercus
incana Bartr. (Fagaceae) [22]. There are no accepted infrataxa.

Bluejack oak forms hybrids with seven other oak species [22,40].

More info for the terms: fuel, tree

Bluejack oak wood is close-grained, hard, and strong; the tree is
usually too small to be of much value except for fuel or posts [40].

Quercus incana is a species of oak known by the common names bluejack oak, upland willow oak, sandjack oak, and cinnamon oak. It is native to the Atlantic and Gulf coastal plains of the United States, from Virginia around Florida to Texas and inland to Oklahoma and Arkansas.