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Useful Tropical Plants

Quercus kerrii

Craib

Fagaceae

+ Synonyms

Cyclobalanopsis kerrii (Craib) Hu

Quercus dispar Chun & Tsiang

Common Name:

Quercus kerrii
Drawing of the fruiting branchlet (Fig 1 only)
Photograph by: Flora of China Illustrations vol. 4, fig. 382, 1
Creative Commons License

General Information

Quercus kerrii is a deciduous tree that can grow from 15 - 40 metres tall. The bole is buttressed[
443
Title
Biotik, Laos
Publication
 
Author
 
Website
http://biotik.org/species_list_laos.html
Publisher
 
Year
0
ISBN
 
Description
Information on more than 100 species of Laotian trees.
].
The tree is harvested from the wild for local use as a food and a source of wood.

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[
293
Title
Poisonous Plants of North Carolina
Publication
 
Author
 
Website
http://www.ces.ncsu.edu/depts/hort/consumer/poison/poison.htm
Publisher
 
Year
0
ISBN
 
Description
An excellent concise but comprehensive guide to toxic plants that grow in N. Carolina. It lists even those plants that are of very low toxicity, including several well-known food plants such as carrots and potatoes.
].

Botanical References

266
Title
Flora of China
Publication
 
Author
 
Website
http://flora.huh.harvard.edu/china/
Publisher
Missouri Botanical Garden Press; St. Louis.
Year
1994
ISBN
 
Description
An excellent, comprehensive resource in 25 volumes. In addition to the botanical information the flora also gives basic information on habitat and some uses. An on-line version is also available.

Range

E. Asia - southern China, Bangladesh, Myanmar, Thailand, Cambodia, Laos, Vietnam.

Habitat

A sub-canopy to canopy tree in moist evergreen, mixed deciduous, lower montane and deciduous Dipterocarp forests; at elevations from 400 - 1,250 metres[
443
Title
Biotik, Laos
Publication
 
Author
 
Website
http://biotik.org/species_list_laos.html
Publisher
 
Year
0
ISBN
 
Description
Information on more than 100 species of Laotian trees.
]. Sparse forests in mountains; 100 - 1,800 metres in China[
266
Title
Flora of China
Publication
 
Author
 
Website
http://flora.huh.harvard.edu/china/
Publisher
Missouri Botanical Garden Press; St. Louis.
Year
1994
ISBN
 
Description
An excellent, comprehensive resource in 25 volumes. In addition to the botanical information the flora also gives basic information on habitat and some uses. An on-line version is also available.
].

Properties

Edibility Rating *  *
Other Uses Rating *  *
HabitDeciduous Tree
Height25.00 m
PollinatorsWind
Cultivation StatusWild

Cultivation Details

Not known

Edible Uses

The fruit (the acorn) is edible in the cooked state[
443
Title
Biotik, Laos
Publication
 
Author
 
Website
http://biotik.org/species_list_laos.html
Publisher
 
Year
0
ISBN
 
Description
Information on more than 100 species of Laotian trees.
]. The oblate seed is 7 - 12mm long and 20 - 28mm wide[
266
Title
Flora of China
Publication
 
Author
 
Website
http://flora.huh.harvard.edu/china/
Publisher
Missouri Botanical Garden Press; St. Louis.
Year
1994
ISBN
 
Description
An excellent, comprehensive resource in 25 volumes. In addition to the botanical information the flora also gives basic information on habitat and some uses. An on-line version is also available.
].
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[
4
Title
A Modern Herbal.
Publication
 
Author
Grieve.
Publisher
Penguin
Year
1984
ISBN
0-14-046-440-9
Description
Not so modern (1930's?) but lots of information, mainly temperate plants.
]. Extracts of the plant can be added to ointments and used for the healing of cuts[
4
Title
A Modern Herbal.
Publication
 
Author
Grieve.
Publisher
Penguin
Year
1984
ISBN
0-14-046-440-9
Description
Not so modern (1930's?) but lots of information, mainly temperate plants.
, ].

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[
20
Title
Companion Planting for Successful Gardening.
Publication
 
Author
Riotte. L.
Publisher
Garden Way, Vermont, USA.
Year
1978
ISBN
0-88266-064-0
Description
Fairly good.
,
K
Title
Plants for a Future
Author
Ken Fern
Description
Notes from observations, tasting etc at Plants For A Future and on field trips.
]..

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[
4
Title
A Modern Herbal.
Publication
 
Author
Grieve.
Publisher
Penguin
Year
1984
ISBN
0-14-046-440-9
Description
Not so modern (1930's?) but lots of information, mainly temperate plants.
,
331
Title
Flora of Guatemala
Publication
 
Author
Standley P.C. & J. A. Steyermark
Website
http://www.archive.org/
Publisher
 
Year
1946 - 1976
ISBN
 
Description
A superb reference, though somewhat dated. Gives lots of plant uses as well as information on plant habit and habitat. The entire flora (13 volumes) can now be downloaded from http://www.archive.org/
].
The bark of oak trees is also usually rich in tannins and can be used as a dyestuff and for waterproofing rope[
331
Title
Flora of Guatemala
Publication
 
Author
Standley P.C. & J. A. Steyermark
Website
http://www.archive.org/
Publisher
 
Year
1946 - 1976
ISBN
 
Description
A superb reference, though somewhat dated. Gives lots of plant uses as well as information on plant habit and habitat. The entire flora (13 volumes) can now be downloaded from http://www.archive.org/
,
K
Title
Plants for a Future
Author
Ken Fern
Description
Notes from observations, tasting etc at Plants For A Future and on field trips.
].

The wood is pale yellow[
443
Title
Biotik, Laos
Publication
 
Author
 
Website
http://biotik.org/species_list_laos.html
Publisher
 
Year
0
ISBN
 
Description
Information on more than 100 species of Laotian trees.
]. It is used in construction[
443
Title
Biotik, Laos
Publication
 
Author
 
Website
http://biotik.org/species_list_laos.html
Publisher
 
Year
0
ISBN
 
Description
Information on more than 100 species of Laotian trees.
].
The wood is used for fuel[
443
Title
Biotik, Laos
Publication
 
Author
 
Website
http://biotik.org/species_list_laos.html
Publisher
 
Year
0
ISBN
 
Description
Information on more than 100 species of Laotian trees.
].

Propagation

Seed - it quickly loses viability if it is allowed to dry out. It can be stored moist and cool, 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[
11
Title
Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement.
Publication
 
Author
Bean. W.
Publisher
Murray
Year
1981
ISBN
-
Description
A classic with a wealth of information on the plants, but poor on pictures.
]. Trees should not be left in a nursery bed for more than 2 growing seasons without being moved or they will transplant very badly.

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