American chestnut

Family

Fagaceae

Habit

Tree

Height

35 m

Spread

12 m

Growth

fast

Lifespan

200 years

First yield

after 7 years

Hardiness

zone 5–8

Shade tolerance

light shade

Soil

Sand, Silt, Clay

Soil moisture

dry – moist

pH

4.5 – 7

Times apply to the northern hemisphere in a temperate climate and shift with altitude and cultivar.

Edible: The nuts resemble those of the European chestnut but stay somewhat smaller, and the flavour is good. They are prepared boiled, roasted or ground into flour.

Other uses: Its tall, straight-stemmed growth made the species one of the most important timber trees of its home range before chestnut blight appeared. The wood is rich in tannin and therefore durable even in contact with the ground.

At up to thirty-five metres the tallest species of the genus, yet with a markedly less spreading crown than the European chestnut — which makes it more interesting for forestry than for fruit growing. Leaves, twigs and buds are hairless, the leaves oblong-lanceolate with a coarsely toothed margin. Its soil and climate requirements match those of the genus: acid, deep and free-draining soils, no waterlogging and no lime. Planting outside resistance programmes is not advisable in areas under blight pressure. Susceptible to: chestnut blight (Cryphonectria parasitica, entering through bark injuries and killing the shoots above the point of attack; this species is the most sensitive of the genus), ink disease (Phytophthora cinnamomi and P. cambivora, root and collar rot on wet, poorly drained soils).

True-to-type propagation is by grafting onto seed-raised rootstocks. The seed is stored cool but frost-free over winter and sown outdoors in spring. For fruit set at least two, better three genetically different individuals are needed. Reintroduction programmes cross deliberately with the Chinese and Japanese chestnut and then select for resistance; pure offspring of this species remain susceptible to the blight.

Pollination is both by wind and by insects. The flowers are visited heavily by bees and other insects and count as valuable bee forage — the flowering period in June and July fills a gap when little else is in bloom. The nuts are eaten by squirrels, dormice and corvids, which also disperse them.

Hit harder by chestnut blight than any other species of the genus: in its home range whole stands have vanished from the landscape and the species is regarded there as all but extinct. It is even more sensitive to the pathogen than the European chestnut. Crossing programmes with the Chinese and Japanese chestnut have been running for decades in order to reintroduce it with resistance bred in.

Eastern North America, from Maine across southern Ontario to Mississippi and from the Atlantic coast to the Appalachians and the Ohio valley. Chestnut blight has collapsed the population from an estimated 3.5 billion trees to a few dozen mature specimens. Isolated plantings in the west of the continent were spared, for instance in British Columbia and Oregon.

Deciduous woodland on the mild-wintered eastern side of the continent, where the species made up as much as a quarter of the tree population and formed part of the canopy. It occupies dry, gravelly to rocky and predominantly acid soils, from the coastal plain up into the low mountain ranges. Light shade is tolerated, but it also thrives in full sun. Limestone soils are avoided.