Common Name: Japanese Chestnut

General Information

Castanea crenata is a deciduous shrub or a tree with an open, rounded crown; it usually grows up to 9 metres tall, though occasionally reaches 15 metres or more[].
A valuable food tree, it is commonly cultivated for its edible seed in Japan, where there are many named varieties[, , ]. The tree is also cultivated as a timber crop and is also sometimes grown as an ornamental and shade tree[].

Known Hazards

None known

Botanical References

, ,

Range

E. Asia - Japan, Korea.

Habitat

Foothills[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	9.00 m
Pollinators	Insects
Self-fertile	No
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Castanea crenata is a very cold-hardy tree, tolerating temperatures down to around -30°c when dormant. It grows best in areas with hot summers, though it has also grown well in more maritime areas with cooler summers[].
Prefers a good well-drained slightly acid loam but succeeds in dry soils[, , ]. Once established, it is very drought tolerant[, , ]. Very tolerant of highly acid, infertile dry sands[]. Averse to calcareous soils but succeeds on harder limestones[, ].
The majority of species in this genus only really thrive in areas with hot summers, though this species is better adapted to British conditions than most[].
Cultivated for its edible seed in Japan, there are many named varieties[, , ]. It is often also cultivated for its seed in America because it is fairly resistant to chestnut blight[, ].
Individual trees are very variable with regard to size of the seed, resistance to blight and astringency of the seed[].
Some cultivars have the largest seeds of any member of this genus.
Trees fruit freely when only 3 - 3.5 metres tall[].
This species is occasionally planted as a timber tree in S. Europe[].
Flowers are produced on wood of the current year's growth[]. Plants are fairly self-sterile[].
All the different Castanea species are interfertile and will hybridize freely with other members of this genus[].
Plants in this genus are notably resistant to honey fungus[].

Cultivated here and in the USA as fruit tree. Planted for erosion control in Japan and experimental cultivation in Italy. Nuts are eaten cooked or roasted in China and Japan, and are exported as foodstuff to the USA and France ("tamba" varieties have especially large nuts). Nuts are mainly used in pastries. Leaves are used for feeding of silkworms in Japan. Bark and leaves produce a black paint used in painting of silk, leather and porcelain. The species is highly resistant to chestnut blight[].

Edible Uses

Seed - raw or cooked[, , ]. A good potato substitute[, , , ]. A source of starch[]. The seeds of this species contain more tannins than any other member of the genus and therefore have a more bitter flavour[]. A very poor flavour, the seed is coarse and of little value[]. Very variable in size and quality, any astringency can be removed by boiling the seed in salty water[]. There are usually 2 - 3 seeds per cupule, each 20 - 30mm in diameter, though seeds of some cultivars can be up to 50mm in diameter[, ].

Medicinal

All parts of the plant contain tannins. The leaves have traditionally been used in herbal medicine, especially in the treatment of whooping cough and lacquer poisoning (caused by Toxicodendron species[].

In trials, extracts of the inner skins (pellicles) of the fruits have shown strong antioxidant activities. They contain a large quantity of polyphenols, especially condensed and hydrolysable tannins[].
Kurigalin, an agallotannin, was isolated from the bark[]
The bark extracts contain high concentrations of ellagic and gallic acids[].

Agroforestry Uses:

Castanea crenata is an excellent soil-enriching understorey plant to grow in open pine forests[].

Other Uses

This species is noted for having resistance to chestnut blight which is the disease that has nearly wiped out the native N. American chestnuts (Castanea dentata and Castanea ozarkensis). It is being used in breeding programmes to instil resistance into the N. American species[, ].

The inner skins (pellicles) of chestnuts are rich in antioxidants and have long been used in East Asia, especially in Korea, as an ingredient in cosmetics[].

The bark, leaves, wood and seed husks all contain tannin[].

The wood is light in weight, hard, strong, very durable. It is used for making furniture, construction, fence posts etc[, ].
The wood is a good fuel, burning well and giving off a lot of heat.

Propagation

Seed - where possible sow the seed as soon as it is ripe in a cold frame or in a seed bed outdoors[]. The seed must be protected from mice and squirrels. The seed has a short viability and must not be allowed to become dry. It can be stored in a cool place, such as the salad compartment of a fridge, for a few months if it is kept moist, but check regularly for signs of germination. The seed should germinate in late winter or early spring. If sown in an outdoor seedbed, the plants can be left in situ for 1 - 2 years before planting them out in their permanent positions. If grown in pots, the plants can be put out into their permanent positions in the summer or autumn, making sure to give them some protection from the cold in their first winter[].