Common Name: American Sweet Chestnut

General Information

Castanea dentata is a deciduous tree, often with a massive bole, that can grow up to 30 metres tall. Most trees in the wild, however, have been severely affected by chestnut blight and are now persisting mostly as multistemmed resprouts 5 - 10 metres tall[].
The American chestnut was one of the most important dominant forest trees of eastern North America prior to 1930 when Chestnut Blight began to affect it. The sweet and edible nuts were a favourite confection in the eastern United States and the tree also provided a good quality wood and tanning bark[]. After 1930, most populations of Castanea dentata were nearly destroyed by the chestnut blight, caused by the introduced fungus Cryphonectria parasitica (Murrill) M. E. Barr [= Endothia parasitica (Murrill) P. J. Anderson & H. W. Anderson]. While chestnuts persist in many localities, the plants are mostly resprouts that rarely, if ever, produce viable seed[].

Known Hazards

None known

Botanical References

, ,

Range

Eastern N. America - Wisconsin to Maine, south to northern Louisiana, Alabama and northern Florida

Habitat

Dry, gravelly or rocky, mostly acid soils[]. This species is virtually extinct in America due to chestnut blight[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	30.00 m
Pollinators	Insects
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

Castanea dentata is a very cold-hardy tree, tolerating temperatures down to around -30°c when dormant. It grows best in areas with hot summers. In areas with cooler summers(even if the winters are mild), such as the maritime regions of the temperate zone, it often grows poorly, failing to properly ripen its wood or fruit, and suffering frost damage over the winter[, ].
Prefers a good well-drained slightly acid loam but succeeds in dry soils and in hot sunny sites[, , , ]. Once established, it is very drought tolerant[, ]. Very tolerant of highly acid, infertile dry sands[]. Averse to calcareous soils but succeeds on harder limestones[, ].
A tree at Kew in 1985 was 15 metres tall and thriving[].
At one time widely cultivated in N. America for its edible seed and its wood, Castanea dentata is now virtually extinct in the wild due to chestnut blight[]. There are some named varieties[]. Trees are possibly becoming resistant, some suckering stands in America are producing fruit[]. Suckers often reach 4 - 6 metres tall before succumbing to blight, but they rarely manage to produce fruit[].
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[].

Edible Uses

Seed - raw or cooked[, , , , ]. Rather on the small side, but they are of very good quality and are the sweetest seeds of any species in this genus[]. The seed contains about 7% fat, 11% protein[]. It can be dried, ground into powder and then be added to cereals when making bread, cakes etc[]. Up to three obovate seeds 18 - 25mm long and 18 - 25mm wide are produced in each seed cupule[].

A delicious oil can be extracted from the seed by crushing the nuts, boiling them in water and then skimming off the oil as it comes to the surface[]. It can be used as a topping for various puddings[].

The roasted nut can be used as a coffee substitute and a chocolate substitute can also be made from it[] (no further details).

Medicinal

A warm water infusion of the leaves has been used to calm the respiratory nerves and promote expectoration[, ]. The infusion has also been used in the treatment of whooping cough but modern opinion is that the leaves are no more than a mild astringent[].

Agroforestry Uses:

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

Other Uses

The bark is a good source of tannin[, , , ]. The dried leaves contain 9% tannin[]. The wood and the seed husks also contain tannin[]. The husks contain 10 - 13% tannin[].

A brown dye is obtained from the bark[].

The wood is light in weight, strong, very durable, easy to split (for shingles etc) but liable to warp when drying. Because of chestnut blight, the wood is no longer really available, but it was of good quality and used in construction, for making cheap furniture, fence posts, decorative trim etc[, , , , , , ].

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[].