Faul Preserve | Quercus arizonica | Arizona white oak

Botanical Family: Fagaceae

Scientific Name: Quercus arizonica

Common Names: Arizona white oak

Botanical Description:

Quercus arizonica is a medium size, evergreen to sub-evergreen tree with an irregular, round, spreading crown, and stout branches (1,2,4). It typically achieves a height of 5-10 meters, but sometimes reaches up to 18 meters (1,2,5). It is found at elevations of 4,000-9,000ft, and more commonly occurs as a shrub at high elevations (1,2,3,5). The bark is scaly, gray, and up to 1 inch thick on older trees (1,4). Young branches are yellowish, becoming a gray color with age (1). The thick, leathery leaves, which are 4-8 cm long, and held by 3-10 mm petioles, have unlobed to toothed margins, and are oblong or obovate in shape (1,3). The upper leaf surface is somewhat lustrous, dark blue green in color, and sparsely pubescent, while the underside is dull, having a prominent midvein, and sparse to dense stellate hairs (1,3). The flowers are wind-pollinated with staminate flowers being 5-7.5 cm long, yellow-green catkins (1,3). Pistillate flowers born on short stems, later developing into cupules that enclose ½ of the fruit (1,2,3). The fruits are 0.8-2.5 cm long, light brown acorns that appear solitary or in pairs (1,2,4).

Ecological Significance:

Quercus arizonica is drought and heat tolerant (2). It occurs in diverse communities and ecosystems ranging from savannas, semidesert grasslands, and chaparral, to Madrean evergreen woodland and pine-oak communities (1,4). It readily hybridizes with other Quercus spp., including Quercus grisea, Quercus mohriana, and Quercus gambelii (1,4). Oaks (Quercus spp.) are keystone species, supporting important food chains and ecological processes. They provide sustenance and shelter for a multitude of animals, plants, fungi, and insects (6,7). Their shade canopy and root systems support soil microbes and invertebrates as well (6,7). Quercus arizonica serves as shelter and a food source for turkeys, javelinas, deer, big horn sheep, quail, and songbirds (2). This species serves as the larval host for a few species of Hespiriidae (skippers) including, Apyrrothrix araxes, Zestusa dorus, and Erynnis meridianus (2,9,10,11).

Ethnobotanical Value: 

Quercus spp. are important medicinal plants widely used in traditional medicine (1,5,8).  Nearly all parts of the plants, including fruit, bark, and leaves, possess medicinal properties. Indigenous tribes used these plants as an antiseptic, and for treatment of gastrointestinal tract disorders (8). The bark, prepared as a tea for internal use, or an ointment for topical application, purportedly has antiseptic properties, and is used as a blood-clotting agent, and in the treatment of toothaches, inflammation, and burns (8). However, further research is needed to confirm these benefits and identify all possible side effects of use (12,13). The fruit is a rich source of nutrients, containing high levels of carbohydrates, proteins, amino acids, lipids, and sterols (8). This species is used for fuel and occasionally for furniture. The wood is close grained, heavy, hard, and strong; however, the trees are rarely straight enough or large enough to be used commercially (4).

Distribution: 

Arizona, New Mexico, Texas, central and northern Mexico

Photos (click for attribution):

Branches | Leaf detail | Acorns