Chestnut
Chestnuts are the deciduous trees and shrubs in the genus Castanea, in the beech family Fagaceae. The name also refers to the edible nuts they produce. They are native to temperate regions of the Northern Hemisphere.
Description
Chestnut trees are of moderate growth rate to fast growth rate. Their mature heights vary from the smallest species of chinkapins, often shrubby, to the giant of past American forests, C. dentata that could reach. Between these extremes are found the Japanese chestnut tree at average; followed by the Chinese chestnut tree at about, then the European chestnut tree around.The Chinese and more so the Japanese chestnut trees are both often multileadered and wide-spreading, whereas European and especially American species tend to grow very erect when planted among others, with little tapering of their columnar trunks, which are firmly set and massive. When standing on their own, they spread on the sides and develop broad, rounded, dense crowns at maturity. The foliage of the European and American species has striking yellow autumn coloring.
Its bark is smooth when young, of a vinous maroon or red-brown color for the American chestnut, grey for the European chestnut. With age, American species' bark becomes grey and darker, thick, and deeply furrowed; the furrows run longitudinally, and tend to twist around the trunk as the tree ages, sometimes reminiscent of a large cable with twisted strands.
The leaves are simple, ovate or lanceolate, long, and 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 eight stamens, or 10 to 12 for C. mollissima. The ripe pollen carries a heavy, sweet odor that some people find too sweet or unpleasant. 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. Two or three flowers together form a four-lobed prickly calybium, which ultimately grows completely together to make the brown hull, or husk, covering the fruits.
Chestnut flowers are not self-compatible, so two trees are required for pollination. All Castanea species readily hybridize with each other.
Fruit
The fruit is contained in a spiny cupule 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. Around the time the fruits reach maturity, the burrs turn yellow-brown and split open in two or four sections. They can remain on the tree longer than they hold the fruit, but more often achieve complete opening and release the fruits only after having fallen on the ground; opening is partly due to soil humidity.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.
The fruit inside these shows a germ with two cotyledons connected to creamy-white flesh throughout. Some varieties have consistently only one embryo per fruit or have only one large fruit per burr, well rounded. The name of varieties with these characteristics may start with "marron" for example marron de Lyon in France, or Marrone di Mugello in Italy.
Chestnut fruit may not exhibit epigeal dormancy. It may germinate right upon falling to the ground in the autumn, with the roots emerging from the seed right away and the leaves and stem the following spring. The germ can lose viability soon after ripening and under drying conditions.
The superior fruiting varieties among European chestnuts have good size, sweet taste, and easy-to-remove inner skins. American chestnuts are usually very small, but sweet-tasting with easy-to-remove pellicles. Some Japanese varieties have very large nuts, with typically difficult-to-remove pellicles. Chinese chestnut pellicles are usually easy to remove, and their sizes vary greatly according to the varieties, although usually smaller than the Japanese chestnut.
Similar species
The unrelated horse chestnuts are not true chestnuts, but are named for producing nuts of similar appearance that are mildly poisonous to humans. True chestnuts should also not be confused with water chestnuts, which are tubers of an aquatic herbaceous plant in the sedge family Cyperaceae. Other species commonly mistaken for chestnut trees are the chestnut oak and the American beech, both of which are also in the Fagaceae family. Brazil nuts, called "Brasil chestnuts" or "chestnuts from Pará" are also unrelated.Taxonomy
Species
Chestnuts belong to the family Fagaceae, which also includes oaks and beeches. The four main species groups are commonly known as American, European, Chinese, and Japanese chestnuts.The taxonomy of the American chestnuts is not completely resolved, particularly between the chinkapins, which are sometimes considered to be the same species. Genetics have indicated the California native "golden chinkapin" is worthy of inclusion in a different genus along with a species from Coastal China. There is also another chestnut, Castanea alabamensis, which may be its own species.
| Subgenus | Image | Scientific name | Common name | Distribution |
| American chestnuts | Castanea dentata | American chestnut | Eastern North America | |
| American chestnuts | Castanea pumila | American or Allegheny chinkapin, also known as "dwarf chestnut" | Southern and eastern United States | |
| American chestnuts | Castanea ozarkensis | Ozark chinkapin | Southeastern and Midwestern United States | |
| Asian chestnuts | Castanea mollissima | Chinese chestnut | China, Vietnam, India, and North Korea | |
| Asian chestnuts | Castanea henryi | Chinese chinkapin, also called Henry's chestnut | China | |
| Asian chestnuts | Castanea seguinii | Seguin's chestnut | China | |
| Asian chestnuts | Castanea crenata | Japanese chestnut, Korean chestnut | Korean Peninsula and Japan | |
| European chestnut | Castanea sativa | sweet chestnut; also called "Spanish chestnut" in the US and the UK | Parts of Southern Europe, the Caucasus, Western Asia and Asia Minor |
Etymology
The name "chestnut" is derived from an earlier English term "chesten nut", which descends from the Old French word chastain. The French word in turn derives from Latin Castanea, which traces to the Ancient Greek word κάστανον. A possible source of the Greek word is the ancient town of Casthanaea in Magnesia. Its location is at the modern village of Keramidi. The town probably took its name, though, from the trees growing around it. In the Mediterranean climate zone, chestnut trees are rarer in Greece because the chalky soil is not conducive to the tree's growth. Kastania is located on one of the relatively few sedimentary or siliceous outcrops. They grow so abundantly there that their presence would have determined the place's name. Still others take the name as coming from the Greek name of Sardis glans – Sardis being the capital of Lydia, Asia Minor, from where the fruit had spread.The name is cited twice in the King James Version of the Bible. In one instance, Jacob puts peeled twigs in the water troughs to promote healthy offspring of his livestock. Although it may indicate another tree, it indicates the fruit was a local staple food in the early 17th century.
These synonyms are or have been in use: Fagus Castanea, Sardian nut, Jupiter's nut, husked nut, and Spanish chestnut.
Ecology
The tree is noted for attracting wildlife. The nuts are an important food for jays, pigeons, wild boar, deer, and squirrels.American and Chinese chinquapins have very small nuts that are an important source of food for wildlife.
Cultivation
History
Europe and the Near East
It has been a staple food in southern Europe, Turkey, and southwestern and eastern Asia for millennia, largely replacing cereals where these would not grow well, if at all, in mountainous Mediterranean areas. Evidence of its cultivation by humans is found since around 2000 BC. Alexander the Great and the Romans planted chestnut trees across Europe while on their various campaigns. A Greek army is said to have survived their retreat from Asia Minor in 401–399 BC thanks to their stores of chestnuts. Ancient Greeks, such as Dioscorides and Galen, wrote of chestnuts to comment on their medicinal properties—and of the flatulence induced by eating too much of it. To the early Christians, chestnuts symbolized chastity. Until the introduction of the potato, whole forest-dwelling communities which had scarce access to wheat flour relied on chestnuts as their main source of carbohydrates. In some parts of Italy, a cake made of chestnuts is used as a substitute for potatoes. In 1583, Charles Estienne and Jean Liébault wrote, "an infinity of people live on nothing else but ". In 1802, an Italian agronomist said of Tuscany that "the fruit of the chestnut tree is practically the sole subsistence of our highlanders", while in 1879 it was said that it almost exclusively fed whole populations for half the year, as "a temporary but complete substitution for cereals".The Hundred Horse Chestnut in the chestnut forests on Mount Etna is the oldest living chestnut tree and is said to be even larger. Chestnut trees particularly flourish in the Mediterranean basin. In 1584, the governor of Genoa, which dominated Corsica, ordered all the farmers and landowners to plant four trees yearly, among which was a chestnut tree – plus olive, fig and mulberry trees. Many communities owe their origin and former richness to the ensuing chestnut woods. In France, the marron glacé, a candied chestnut involving 16 different processes in a typically French cooking style, is always served at Christmas and New Year's time. In Modena, Italy, they are soaked in wine before roasting and serving, and are also traditionally eaten on Saint Simon's Day in Tuscany. In the Romagna region, roasted chestnuts are often served with a traditional wine, the Cagnina di Romagna. It is traditional to eat roasted chestnuts in Portugal on St. Martin's Day.
Their popularity declined during the last few centuries, partly due to their reputation of "food for poor people". Many people did not want to take chestnut bread as "bread" because chestnut flour does not rise. Some slandered chestnut products in such words as the bread which "gives a sallow complexion" written in 1770, or in 1841 "this kind of mortar which is called a soup". The last decades' worldwide renewal may have profited from the huge reforestation efforts started in the 1930s in the United States to establish varieties of C. sativa which may be resistant to chestnut blight, as well as to relieve the strain on cereal supplies.
The main region in Italy for chestnut production is the Mugello region; in 1996, the European Community granted the fruit Protected Geographic Indication status to the . It is markedly sweet, peels easily, is not excessively floury or astringent, and has notes of vanilla, hazelnut, and, more subtly, fresh bread. It has no unpleasant aroma, such as yeast, fungus, mold, or paper, which sometimes occur with other chestnuts. The main regions in France for chestnut production are the départements of Ardèche, Var, Cévennes and the Lyon region. France annually produces over 1,000 metric tons, but still imports about 8,000 metric tons, mainly from Italy.
In Portugal's archipelago of Madeira, chestnut liquor is a traditional beverage, and it is gaining popularity with the tourists and in continental Portugal.
In Britain, pre-historic pollen records show that the species is an introduced, and not a native, tree. It is associated with sites of Roman-era occupation, but it was already established by that time. Boundary records compiled in the reign of King John showed the famous Tortworth Chestnut in South Gloucestershire was already a landmark; it was known by the name of "Great Chestnut of Tortworth" in the days of Stephen. This tree measured over in circumference at from the ground in 1720.