Common Name: Post Oak

General Information

Quercus stellata is a deciduous tree with a dense, rounded canopy of spreading, twisted branches; it usually grows up to 20 metres tall but in favoured sites can reach 30 metres, whilst in the drier parts of its range it is often only 9 - 12 metres tall. The bole is usually around 30 - 60cm in diameter but can reach 120cm[, ].
A valuable timber species in N. America, where it is harvested on a commercial basis. The tree is also harvested for local use as a food, medicine and source of materials. It is used in soil stabilization projects and is often grown as an ornamental in parks, as a street tree etc[].
Quercus stellata has a wide range and occurs regularly throughout, forming pure stands in parts of its range. Though the population size is not entirely known, because of its abundance throughout its range, the population size is assumed to be large enough to be outside the thresholds of any threatened category. 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

, ,

Range

South-eastern N. America - southern Iowa to Massachusets, south to Texas and northern Florida

Habitat

Rocky or sandy ridges and outcrops, also in dry woodlands in a variety of soils including gravelly, sandy, poor upland soils and heavy moist loamy soils, where it reaches its greatest height; at elevations from 900 - 1,500 metres[, ].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	15.00 m
Growth Rate	Slow
Pollinators	Wind
Cultivation Status	Ornamental, Wild

Cultivation Details

Quercus stellata is a very cold-hardy tree, tolerating temperatures down to around -25°c when dormant. 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[, ].
Young plants tolerate reasonable levels of side shade[], but older plants grow best in a sunny position[]. Adapts to a wide variety of soil conditions from poor dry sandy soils to moist heavy loams, preferring acidic soils[]. Prefers a good deep fertile loam which can be on the stiff side[, ]. Tolerates moderate exposure and salt-laden winds, surviving well but being somewhat stunted[]. Established plants are very drought tolerant[, ].
With an attractive crown with strong horizontal branches, Quercus stellata is considered an ideal shade tree for parks and is often used in urban forestry[]..
A slow-growing drought resistant tree, it takes 20 - 30 years before it produces seed[]. It then usually produces a good crop of seeds every 2 - 4 years[].
Trees can live for 300 - 400 years[].
The tree flowers on new growth produced in spring, the seed ripening in its first year[, ].
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[].
Quercus stellata is susceptible to most insects and diseases that attack eastern oak species. The Chestnut Blight Fungus (Cryphonectria parasitica) attacks Post Oak throughout most of its range[].
Plants in this genus are notably resistant to honey fungus[].

Edible Uses

Seed - raw or cooked[, , ]. A sweet taste[]. The light brown, ovoid or globose seed can be 10 - 20mm long and 8 - 20mmwide[].
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 is a coffee substitute[, ].

Medicinal

The bark is astringent, disinfectant, emetic, febrifuge and tonic[]. An infusion is used in the treatment of chronic dysentery, indigestion, asthma, lost voice and intermittent fevers[]. The bark can be chewed to treat mouth sores[]. An infusion of the bark can be used as a wash on sore and chapped skin[].

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[, ].

Agroforestry Uses:

The tree is planted for soil stabilization on dry, sloping, stony sites, which are unsuitable for other species[].

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 bark is used as a decorative and protective mulch in landscaping[].

The wood is very heavy, hard, close grained, very durable in contact with the soil but difficult to cure. It weighs about 52lb per cubic foot. It is largely used for fencing, lumber, furniture and fuel[, , , , , , ].
This is a valuable timber species because the wood is very durable and classified as moderately to very resistant to decay. It is used for railroad ties, mine, timbers, flooring, siding, planks, construction timbers and fence posts[].
The wood of many Oak species is a favoured fuel - burning well and giving off a lot of heat[].

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.