Common Name: Shin Oak

General Information

Quercus gambelii is a deciduous shrub or a small tree. It can grow from 2 - 10 metres or more tall, with some mature specimens on favoured sites exceeding 20 metres. The plant can spread at the roots and, when growing as a shrub, sometimes forms a dense thicket[270. 1050].
The tree is harvested from the wild for local use as a food, medicine and source of materials. It has the potential for use in soil stabilization projects.
Quercus gambelii covers a large area, has no current threats and exists in many areas as a species that crowds out other native ground cover. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

All parts of the plant contain tannins. Whilst tannins are found in many foods, and have a range of medicinal uses. They are usually only present in low concentrations. In some foods made from oaks (particularly the seeds), the tannin content can be quite high unless the food is treated to reduce tannin content.
Tannins are only of low toxicity and, because of their bitter taste and astringency, are unlikely to be eaten in large quantities. However, if they are taken in excess, they can cause stomach pains; constipation followed by bloody diarrhoea: excessive thirst; and excessive urination[].

Botanical References

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Range

Western N. America - Nevada to Wyoming, south to Arizona, Texas and northern Mexico.

Habitat

Montane conifer, oak-maple, and higher margins of pinyon-juniper woodlands; at elevations from 1,000 - 3,030 metres[]. Dry foothills and lower mountain slopes; at elevations from 1,350 - 2,800 metres[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	4.50 m
Growth Rate	Slow
Pollinators	Wind
Cultivation Status	Wild

Cultivation Details

Quercus gambelii is a very cold-hardy tree, tolerating temperatures down to around -30°c when dormant. It can succeed in areas where the growing season is as little as 60 - 90 days, though it does not fruit in such conditions[, ]. It grows best in areas with hot summers. In areas with cooler summers, such as the maritime regions of the temperate zone, it often grows poorly, failing to properly ripen its wood and suffering frost damage over the winter[, ].
Prefers a good deep fertile loam which can be on the stiff side[, ]. Young plants tolerate reasonable levels of side shade[]. Tolerates moderate exposure, surviving well but being somewhat stunted[]. Established plants are very drought tolerant[, ].
A slow growing plant that often produces suckers and grows as a thicket[, ], it occasionally makes a small tree[]. Plants growing on dry 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[].
Seed production is cyclical, a year when good crops are produced is followed by several years of light production[].
The tree flowers on new growth produced in spring, the seed ripening in its first year[, ].
One population from San Juan County, Utah, with larger fruit but otherwise not differing from typical Quercus gambelii , has been recognized as Quercus gambelii var. bonina Welsh[].
Seedlings soon develop a taproot and become intolerant of root disturbance, they should be planted into their permanent positions whilst young[].
Hybridizes freely with other members of the genus[]. Numerous hybrids of Quercus gambelii with various scrub oaks have been reported, including Quercus grisea and Quercus turbinella[].
This species is notably resistant to honey fungus[, ].

Edible Uses

Seed - raw or cooked[, ]. A staple food for several native North American Indian tribes[]. A sweet taste[, , , , ]. The seed can range from 8 - 33mm long and 7 - 18mm wide[].
The seed is usually cooked before eating, though it can also be eaten raw. It can be eaten whole, though it is more commonly dried, then ground into a powder and used as a thickening in stews etc or mixed with cereals for making bread.
In some species, especially many of those classified as 'white oaks', the seeds are low in tannins and have a more or less sweet and agreeable flavour. The seed of most species, however, have a very bitter flavour, due especially to the presence of tannins. In these species there are various processes that can remove or at least reduce the amount of these bitter substances (although other water-soluble substances, including some minerals, will also be removed).
Tannins are water-soluble and therefore the easiest way to remove or reduce tannin levels is by soaking in water. A few different methods are listed:-
A traditional method of preparing the seed was to bury it in boggy ground overwinter and allow the wet soil to gradually leach the tannins. The germinating seed was dug up in the spring when it would have lost most of its astringency and bitterness.
Another method was to wrap the seeds in a cloth bag and place them in a stream for several weeks.
Drying the seed and grinding it to a powder before soaking speeds up the process. The fastest method is to use hot water, by cooking the powder and changing the water several times until the cooking water is no longer bitter. Alternatively, you can use cold water (which is reported to produce the best quality flour). In this case, you soak the powdered seed in cold water for 12 - 24 hours then discard the water. Repeat this process for a number of times until the soak water is no longer bitter.

The roasted seed of many Quercus species has been used as a coffee substitute.

Medicinal

Quercus (oak) species are used in the traditional medicine of many cultures, being valued especially for their tannins. Various parts of the plant can be used, most frequently it is the leaves, bark, seeds, seed cups or the galls that are produced as a result of insect damage. A decoction or infusion is astringent, antibacterial, antifungal, antiseptic, styptic and haemostatic. It is taken internally to treat conditions such as acute diarrhea, dysentery and haemorrhages. Externally, it is used as a mouthwash to treat toothache or gum problems and is applied topically as a wash on cuts, burns, various skin problems, haemorrhoids and oral, genital and anal mucosa inflammation[]. Extracts of the plant can be added to ointments and used for the healing of cuts[, ].

The acorns have been eaten to give greater sexual potency[].

The root bark is analgesic and cathartic[]. A decoction has been used to treat postpartum pain and facilitate delivery of the placenta[].

Agroforestry Uses:

Although it has not been used extensively in the environmental rehabilitation of disturbed sites, this species does have a moderate value for long-term revegetation. The extensive root system helps provide soil stability and reduce erosion[]

Other Uses

The leaves of most species in this genus are more or less rich in tannins. A mulch of the partially decayed leaves can be placed around vulnerable plants in order to repel slugs, snails, grubs etc, and these will in time break down to add humus and nutrients to the soil. Fresh leaves should be used with caution, however, since as these decay they utilize some of the nitrogen in the soil and thus can inhibit plant growth[, ]..

Oak galls are excrescences that are sometimes produced in great numbers on the tree and are caused by the activity of the larvae of different insects. The insects live inside these galls, obtaining their nutrient therein. When the insect pupates and leaves, the gall can be used as a rich source of tannin, that can also be used as a dyestuff and is also used by many cultures to make ink[, ].
The bark of oak trees is also usually rich in tannins and can be used as a dyestuff and for waterproofing rope[, ].

The seed cups are used as buttons[].

The wood is hard, heavy, close-grained. The trees are generally too small to be of use commercially, though the wood is used locally for lumber[]. Small-diameter stems that are reasonably straight make ideal fenceposts that are decay-resistant and more durable than many other oaks. Untreated posts outlast both Quercus emoryi and Quercus arizonica[].
The wood is an excellent fuel, giving off a good amount of heat with little soot or smoke[, , ].

Propagation

Seed - it quickly loses viability if it is allowed to dry out. It can be stored moist and cool overwinter but is best sown as soon as it is ripe in an outdoor seed bed, though it must be protected from mice, squirrels etc. Small quantities of seed can be sown in deep pots in a cold frame. Plants produce a deep taproot and need to be planted out into their permanent positions as soon as possible, in fact seed sown in situ will produce the best trees[]. Trees should not be left in a nursery bed for more than 2 growing seasons without being moved or they will transplant very badly.
Division of suckers in the dormant season[].