Chestnut

Chestnut (Castanea), (including chinkapin or chinquapin) is a genus of eight or nine species of deciduous trees and shrubs in the beech family Fagaceae, native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce.

Most of the species are large trees growing to 20-40 m tall, but some species (the chinkapins) are smaller, often shrubby. The leaves are simple, ovate or lanceolate, 10-30 cm long and 4-10 cm broad, with sharply pointed, widely-spaced teeth, with shallow rounded sinuses between. The flowers are catkins, produced in mid summer; they have a heavy, unpleasant odour. The fruit is a spiny cupule 5-11 cm diameter, containing one to seven nuts.

The name Castanea comes from the old Latin name for the Sweet Chestnut.

Chestnuts should not be confused with either horse-chestnuts (genus Aesculus), or water-chestnut (family Cyperaceae); these are named for producing respectively nuts of similar appearance, and tubers of similar taste.

Ecology

Chestnut trees thrive on neutral and acidic soils, such as soils derived from granite, sandstone, or schist, and do not grow well on alkaline soils such as chalk.

The nuts are an important food for jays, pigeons, wild boar and squirrels. Several insects, notably the weevil Curculio elephas (chestnut weevil), also feed on the seeds.

The leaves are used as a food plant by the larvae of some Lepidoptera species ( butterflies and moths); see list of Lepidoptera that feed on chestnut trees.

Diseases

A fungal disease, chestnut blight Cryphonectria parasitica, affects chestnuts. The eastern Asian species have co-evolved with this disease and are moderately to very resistant to it, while the European and North American species, not having been exposed to it in the past, have little or no resistance.

Early in the 20th century, chestnut blight was introduced to North America by the importation of Asian chestnut plants. This resulted in the subsequent destruction of an estimated 4 billion American Chestnut trees over the next 40 years, and what had been the most important tree throughout the east coast was reduced to insignificance. The American chinkapins are also very susceptible to chestnut blight. The European and west Asian Sweet Chestnut is susceptible, but less so than the American.

The resistant species (particularly Japanese Chestnut and Chinese Chestnut but also Seguin's Chestnut and Henry's Chestnut) have been used in breeding programs in the US to create hybrids with the American Chestnut that are also disease resistant.

Uses

Nuts

The nuts are an important food crop in southern Europe, southwestern and eastern Asia, and also in eastern North America before the arrival of chestnut blight. In southern Europe in the Middle Ages, whole forest-dwelling communities which had scarce access to wheat flour relied on chestnuts as their main source of carbohydrates.

The nuts can be eaten candied, boiled or roasted; candied chestnuts are often sold under the French name marrons glacés or Turkish name kestane şekeri. Another important use of chestnuts is to be ground into flour, which can then be used to prepare bread, cakes and pasta.

Another little known use is to eat chestnuts raw by just peeling them (almost unknown in North-America but customary at least in Northwest Europe). When chestnuts are fresh from the field/store, peeling is not easy. However, after leaving them out at room temperature for 24-48 hours, using a simple small, pointed kitchen knife will allow the consumer to easily peel away the outside shell. Next, you peel the thinner inside skin. Wash, and if present cut away contamination, and eat. Chestnuts' taste may vary slightly from one to the next but is somewhat sweet and certainly unique. After leaving chestnuts out for more than 5-7 days the quality starts to degrade.

Chestnut-based recipes and preparations are making a comeback in Italian cuisine, as part of the trend toward rediscovery of traditional dishes.

Other products

The wood is similar to oak wood in being decorative and very durable. Due to disease, American Chestnut wood has almost disappeared from the market. Although quantities of Chestnut can still be obtained as reclaimed lumber, it is difficult to obtain large timber from the Sweet Chestnut due to the high degree of splitting and warping when it dries. The wood of the Sweet Chestnut is most commonly used in small items where durability is important, such as fencing and wooden outdoor cladding ('shingles') for buildings. In Italy, it is also used to make barrels used for aging balsamic vinegar.

In southern England (particularly in Kent), sweet chestnut has traditionally been grown as coppice, being re-cut every ten years or so on rotation for poles, used for firewood, fencing (fence posts and chestnut paling) and especially to support the strings up which hops are grown.

The bark of chestnuts was also a useful source of natural tannins, used for tanning leather before the introduction of synthetic tannins.

Cultivation

Chestnuts grown for nut production are grown in orchards with wide spacing between the trees to encourage low, broad crowns with maximum exposure to sunshine to increase nut production. On alkaline soils, chestnuts can be grown by grafting them onto oak rootstocks. Most wood production is done by coppice systems, cut on a 12 year rotation to provide small timber which does not split as badly as large logs.

Chestnuts for planting require storage in moist sand and chilling over the winter before sowing; drying kills the seed and prevents germination.