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Blackjack Oak

The Quercus Emoryi is commonly known as Bellota, Blackjack Oak, as well as Emory Oak

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Growing Regions

The range of Emory oak extends from central Arizona eastward through southern New Mexico into western Texas [23,57,64,96,104]. Its range continues southward through northern Mexico from Chihuahua west to Sonora and south to Durango [35,48,96,103].

     

General Information

The currently accepted scientific name of Emory oak is Quercus emoryi Torr. It is a member of the oak family (Fagaceae) [23,57]. No infrataxa are recognized. Where distributions overlap in Texas, Emory oak hybrizes with graceful oak (Q. graciliformis) to form Tharp oak (Q. xtharpii C. H. Mull.) and Graves oak (Q. gravesii) to form robust oak (Q. xrobusta C. H. Mull.) [23,96,105,121].

Emory oak occurs in many communities along diverse elevational and
moisture gradients from pine-oak (Pinus spp.-Quercus spp.), Madrean
evergreen, and open oak woodlands to interior chaparral, semidesert
grasslands, and savannas [15,32,67,78,123].

Emory oak is a codominant or subdominant species in all community types
of the pine-oak woodlands of higher elevations [8,27,85].  It is an
indicator species in ponderosa pine (Pinus ponderosa), Apache pine (P.
engelmannii), and Chihuahua pine (P. leiophylla var. chihuahuana) habitat
types and border pinyon (P. discolor) community types [1,76,82,116].

In pinyon-juniper (Pinus spp.-Juniperus spp.) woodlands, Emory oak is a
codominant or an indicator species [17,47,51,74,80].  It is an important
understory species in pinyon-juniper stands [94].

Emory oak is dominant or codominant with Arizona white oak (Q.
arizonica), Mexican blue oak (Q. oblongifolia), and juniper in Madrean
evergreen and open oak woodland series [6,16,42,79,85,98].  Emory oak is
the most characteristic tree of encinal or oak woodlands in the border
region of Mexico and the United States [57,64,66].  In the Chihuahuan
Desert, Emory oak is codominant with gray oak (Q. grisea), Graves oak,
and Mexican pinyon (Pinus cembroides) [24,46,116].

Emory oak is occasionally present in the interior chaparral as a
subdominant shrub or as one of the taller evergreen oaks.  These
interior chaparral communities occur discontinuously and extend into the
wetter Madrean evergreen woodland [40,58,59,91,124].

Emory oak, gray oak, and Chisos oak (Q. chisoensis) form savannas at the
periphery of grama (Bouteloua spp.)-bluestem (Andropogon spp.)
associations [30,32].  Emory oak is a minor species in open savannas of
velvet mesquite (Prosopis velutina)-turpentine bush (Ericameria
laricifolia)-burroweed (Isocoma tenuisecta) associations [122].

Emory oak is known as an upland species but also occurs in riparian
associations.  It is a codominant to infrequent tree in Arizona sycamore
(Platanus wrightii) and Arizona walnut (Juglans major) community types
[61,65,112,115].  Emory oak occurs in mixed broadleaf community and
vegetation types with Arizona cypress (Cupressus arizonica) [98].

Some of the publications in which Emory oak is listed as a dominant or
indicator species are:

(1)  Classification of the forest vegetation on the National Forests of
       Arizona and New Mexico [1]
(2)  Forest and woodland habitat types (plant associations) of Arizona
       south of the Mogollon Rim and southwestern New Mexico [6]
(3)  Forest habitat types south of the Mogollon Rim, Arizona and New
       Mexico [31]
(4)  Classification of mixed broadleaf riparian forest in Tonto
       National Forest [61]
(5)  A forest habitat type classfication of southern Arizona and its
       relationship to forests of the Sierra Madre Occidental of Mexico [82]
(6)  Plant communities of Texas (Series level): February 1992 [116].

Succulent species associated with Emory oak but not previously mentioned
in Distribution and Occurrence include Echinocereus ledingii,
Mammillaria viridiflora, and Opuntia spinosior [56].

Much of the information presented here is attributed to:
Pavek, Diane S. 1994. Quercus emoryi. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available at USDA Forest Service.

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