Chestnut is deciduous tree in the Fagaceae family; genus: Castanea.
There are 9 different species of chestnut native to temperate regions of the Northern Hemisphere.
The four main species are commonly known as European, Chinese, Japanese, and American chestnuts, some species called chinkapin or chinquapin.
It has a lifespan of 200 to 800 years, depending on the species.
Their mature heights vary from the smallest species of chinkapins reaching from 2 to 8 meters (6.5-26 feet), to the giant of past American forests (Castanea dentata) reaching up to 60 meters (200 feet) in height, and 3.5 meters (12 feet) in diameter; Between these extremes are found the Japanese chestnut (C. crenata) at 10 m average; followed by the Chinese chestnut (C. mollissima) at about 15 m, then the European chestnut (C. sativa) 20–35 m (66–115 ft).
Chestnut tree has reddish-brown or grey bark that is smooth in young trees but becomes rough and furrowed in old trees. The bark often has a net-shaped (retiform) pattern with deep furrows or fissures running spirally in both directions up the trunk.
The leaves are simple, ovate or lanceolate, 10–30 cm (4-12 in) long and 4–10 cm (1.5-4 in) wide, with sharply pointed, widely spaced teeth, with shallow rounded sinuates between.
The flowers follow the leaves, appearing in late spring or early summer or into July. They are arranged in long catkins of two kinds, with both kinds being borne on every tree. Some catkins are made of only male flowers, which mature first. Each flower has 8-12 stamens. Other catkins have these pollen-bearing flowers, but also carry near the twig from which these spring, small clusters of female or fruit-producing flowers. [Photo: Male chestnut flowers]
Chestnut flowers are not self-compatible, so two trees are required for pollination. Since they are fragrant, flowers easily attract insects which transfer pollen from one tree to another and perform pollination successfully.
Two or three flowers together form a four-lobed prickly calybium, which ultimately grows completely together to make the hull, or husk, covering the fruits.
The fruit is contained in a spiny (very sharp) cupule 5–11 cm (2-4.3 in) in diameter, also called “bur” or “burr“. The burrs are often paired or clustered on the branch and contain one to seven nuts according to the different species, varieties, and cultivars.
The chestnut fruit has a pointed end with a small tuft at its tip , and at the other end, a hilum – a pale brown attachment scar. In many varieties, the fruit is flattened on one or two sides. It has two skins. The first one is a hard, shiny, brown outer hull or husk, called the pericarpus; the industry calls this the “peel”. Underneath the pericarpus is another, thinner skin, called the pellicle or episperm. The pellicle closely adheres to the seed itself, following the grooves usually present at the surface of the fruit. These grooves are of variable sizes and depths according to the species and variety.
All species except American chestnut are numerous in the wild.
It is estimated that between 3 and 4 billion American chestnut trees were destroyed in the first half of the 20th century by blight (fungal disease). Very few mature specimens of the tree exist within its historical range.
The Japanese chestnut (kuri) was in cultivation before rice and the Chinese chestnut (C. mollissima) possibly for 2,000 to 6,000 years.
The Hundred-Horse Chestnut is the largest and oldest known chestnut tree in the world. Located on Linguaglossa road in Sant’Alfio, on the eastern slope of Mount Etna in Sicily it is generally believed to be 2,000 to 4,000 years old. It is a Sweet Chestnut (Castanea sativa, family Fagaceae). Guinness World Records has listed it for the record of “Greatest Tree Girth Ever”, noting that it had a circumference of 57.9 m (190 ft) when itwas measured in 1780. Above-ground the tree has since split into multiple large trunks, but below-ground these trunks still share the same roots.
Chestnut is of the same family as oak, and likewise its wood contains many tannins. This renders the wood very durable, gives it excellent natural outdoor resistance, and saves the need for other protection treatment.
Chestnuts depart from the norm for culinary nuts in that they have very little protein or fat, their calories coming chiefly from carbohydrates. They are the only “nuts” that contain vitamin C.
Chestnut can be consumed raw, baked, boiled or roasted. It also can be dried and milled into flour, which can then be used to prepare breads, cakes, pies, pancakes, pastas, polenta or used as thickener for stews, soups, and sauces.
Roman soldiers were given chestnut porridge before going into battle.
The name “chestnut” is derived from an earlier English term “chesten nut”, which descends from the Old French word chastain (Modern French, châtaigne).
Chestnuts should not be confused with: horse chestnuts (genus Aesculus), which are not related to Castanea and are named for producing nuts of similar appearance, but which are mildly poisonous to humans, nor should they be confused with water chestnut (family Cyperaceae), which are also unrelated to Castanea and are tubers of similar taste from an aquatic herbaceous plant. Other trees commonly mistaken for chestnut trees are the chestnut oak (Quercus prinus) and the American beech (Fagus grandifolia), both of which are also in Fagaceae.
In George Orwell’s 1984 the chestnut tree is used in poems recited throughout, referring to nature, modern life, and lies as in the saying: ‘that old chestnut‘.