Quercus gambelii

Gambel oak

Fagaceae

The Basics

Taxonomy: Kingdom - Plantae (plants). Subkingdom - Tracheobionta (vascular plants). Superdivision - Spermatophyta (seed plants). Division - Magnoliophyta (Flowering plants). Class - Magnoliopsida. Order - Fagales. Family - Fagaceae (Beech family). Genus -Quercus L. Species - Quercus gambelii Nutt

Ecology: Canopy suppression is a successional trend when Gambel oak is associated with bigtooth maple, white fir, ponderosa pine, Rocky Mountain juniper, or Colorado pinyon. Across its range, Gambel oak occupies a seral, postfire successional stage with late successional associates more susceptible to fire. Gambel oak is listed as a persistent seral stage in the ponderosa pine of northern Arizona, with he majority of Gambel oak occurring as trees. Populations of Gambel oak increase with disturbance in ponderosa pine woodlands

Identification

Shrubs or trees , deciduous, shrubs sometimes clumped and spreading, trees small or moderately large. Bark gray or brown, scaly. Twigs brown or reddish brown with few, inconspicuous lenticels, 1.5-2.5 mm diam., glabrous or stellate-pubescent. Buds brown, ovoid, ca. 3 mm, apex acute or obtuse, sparsely pubescent, becoming glabrate. Leaves: petiole l0-20 mm. Leaf blade elliptic to obovate or oblong, deeply to shallowly 4-6-lobed, (40-)80-120(-160) (25-)40-60(-100) mm, membranous, base truncate to cuneate, margins entire or coarsely toothed, lobes oblong, rounded or subacute, sinuses acute or narrowly rounded at base, reaching more than 1/2 distance to midrib, secondary veins 4-6 on each side, each passing into lobe, branched, apex broadly rounded; surfaces abaxially dull green, sometimes glaucous, densely velvety with erect 4-6-rayed hairs, sometimes glabrate or persistently villous only near midribs, secondary veins prominent, adaxially lustrous dark green, appearing glabrate, microscopically pubescent, secondary veins slightly raised. Acorns solitary or paired, subsessile or on peduncle to 10(-30) mm; cup deeply cup-shaped, 5-8(-17) mm deep 7-l5(-25) mm wide, enclosing 1/4-1/2 nut, base round, margin thin, scales closely appressed, ovate, markedly tuberculate, proximally gray-tomentulose; nut light brown, ovoid to ellipsoid, (8-)12-15(-33) 7-12(-18) mm. Cotyledons distinct.

Threats

Fire effects: Gambel oak is a fire-adapted species. It responds to fire by vegetative sprouting from the lignotuber and rhizomes. Tree forms may survive low-severity fire.

Reproduction

Seed Production and Dissemination - Gambel oak reproduces by seed and vegetatively.Production of mature flowers is directly related to moisture availability. Xeric sites often fail to produce mature female flowers, yet male catkins are produced in abundance. On moist sites, flowers of both sexes are produced in large numbers [75]. Acorn production in Arizona was directly related to moisture availability, averaging 188,000 mature acorns/acre (464,548/ha) and over 331,000 per acre (817,900/ha) in heavy moisture years. Although Gambel oak generally possesses distinct male and female inflorescences on a single plant, Tucker and others observed an inflorescence containing both anthers and pistils in Utah. The following year strictly monoecious flowers were produced. Female flowers are found throughout the Gambel oak canopy while male flowers are almost exclusively located at the top

Vegetative Reproduction - Gambel oak has strong vegetative reproduction capabilities. In most of its range, Gambel oak regeneration depends more on sprouting than establishment from seed. The large underground structure of Gambel oak supports rapid and extensive sprouting following top removal. In Utah vegetative spread of Gambel oak thickets averaged 4-inches (10 cm) per year, with lows of 1.5 inches (3.8 cm) and a high of 12 inches (30.5 cm). Vegetative reproduction occurs through adventitious buds on lignotubers and freely branched rhizomes . A large difference in ability to regenerate by cloning exists between the southern and northern range of Gambel oak. In Arizona and New Mexico, groupings usually consisted of 1 to 7 ramets per clone compared to 100 to 1,000 ramets per clone observed in the north.

Species Distribution

Citation

USDA Plants Database
USDA, NRCS. 2016. The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA.

USFS Plant Database
Habeck, R. J. 1992. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.

Flora of North America
Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+ vols. New York and Oxford.