Common Name: Sawthorn Oak

General Information

Quercus acutissima is a deciduous tree with a moderately dense, rounded, broadly pyramidal canopy; it can grow up to 20 metres tall[]. The straight, cylindrical bole is slender, often branching from low down[, ].
The tree is harvested from the wild for local use as a food, medicine and source of materials. Foods made from the seeds are sold in local markets in Korea[]. The plant is often cultivated in China as a coppiced tree for fuel and charcoal[], and is grown as an ornamental and shade tree[].
Quercus acutissima is a widely distributed species. Like many other oaks, it is used as a source of wood and has various medicinal properties. These uses do not currently appear to be posing a global threat to the species. 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

E. Asia - China, Japan, Korea, northern India, Nepal. Myanmar, Thailand, Laos, Vietnam.

Habitat

Often forming pure forests or growing with Pinus species, at elevations up to 2,200 metres[, ].

Properties

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

Cultivation Details

Quercus acutissima 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[, ].
Tolerant of a wide range of soils, but prefers a good deep fertile loam which can be on the stiff side[, , ]. Somewhat lime tolerant[, ]. Young plants tolerate reasonable levels of side shade[]. Tolerates moderate exposure, surviving well but being somewhat stunted[].
Seedlings soon develop a taproot and become intolerant of root disturbance, they should be planted into their permanent positions whilst young[].
Plants can commence bearing acorns when around 10 years old[].
The seed takes about 18 months to ripenr[, ].
Plants are tolerant of urban pollution[].
This species is closely related to Quercus variabilis[].
Hybridizes freely with other members of the genus[].
Plants in this genus are notably resistant to honey fungus[].

Edible Uses

Seed - cooked[, ]. The seed is up to 25mm long[].
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 Korea the seeds are processed into a popular gelatin-like food known as 'dotori muk' that is commonly sold in markets, restaurants etc[].
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.

Young leaves - cooked. A famine food, only used when all else fails[].

The roasted seed is a coffee substitute.

Medicinal

The stem bark is used to clean foul sores[].
The drug 'bokusoku' is produced from the bark in Japan[].

The seeds are used in the treatment of diarrhoea, menorrhagia and gastrointestinal hypertrophy[].

The cupule (seed cup) is astringent[].

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[, ].

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[, ].
A black dye is obtained from the seed cups[].

The cut logs are used as a growing medium for the cultivation of Shiitake mushrooms[].

Wood - we have no specific information for properties of this wood, but in general oak timber is noted for its strength, durability, and beauty, The wood is used for boat building and construction[].
The wood is used for fuel and charcoal[, ].

Propagation

Seed - quickly loses viability if 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 but 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.