©Chestnut Traders 2002
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Chestnuts belong to the botanical family Fagaceae, as do beeches and oaks. All chestnut species are native to the northern hemisphere. The chestnut (Castanea) is not to be confused with the ornamental flowering horse chestnut (Aesculus), from which one gets 'conkers', or the water chestnut (Eleocharis tuberosa).

The large, edible seed of the chestnut tree is produced inside a prickly case, called a burr. In late summer/autumn (March to mid-May in New Zealand), the burr splits open allowing the chestnuts to fall free. The nuts are unlike other nuts in their consistency and storage ability, but are more like potatoes. It is possibly the most important temperate-zone nut crop, outranked only by the more tropical coconut and peanut. Unlike many other crops, chestnuts tend to produce consistently year on year.

There are four main species of chestnut:

• Castanea crenata (Japanese). Small to medium sized tree (up to 10m tall and 15m wide), typically with many wide spreading branches. Produces large nuts, whose skins are often difficult to remove.
• C. dentata (American). The largest growing and straightest-trunked of all the chestnut species. The nuts are typically very small, but quite sweet and easily peeled. Chestnut blight has decimated this species in its native environment.
• C. mollissima (Chinese). Medium sized tree, often multi branched and wide spreading. The nuts come in a wide range of sizes, but are typically smaller and easier to peel than C.crenata.
• C. sativa (European). A large, wide-spreading tree (up to 15m tall and 20m wide), originating from around Turkey and the Black Sea. The nuts are variable, but superior varieties are good sized, sweet and easy to peel.

Chestnuts have been cultivated for centuries. The oldest surviving records that mention chestnut cultivation come from Asia, where the Chinese chestnut has been cultivated for up to 6,000 years and the Japanese chestnut for at least 900 years. In Europe, the Greeks are thought to have introduced the chestnut from Asia Minor to the Mediterranean area, where it has been cultivated for at least 3,000 years. The Romans introduced chestnuts to north-west and central Europe.

One of the most celebrated chestnut trees is the Castagno di Cento Cavalli, growing on Mt Etna, which was visited by Bryon in 1770. He found it to be "a hollow shell, which looked rather like a group of five trees growing together than a single tree". Bryon made its girth 204 ft. It apparently still fruits freely. There are also four other enormous chestnut trees on Mt Etna, "all sounder and much more beautiful than the Castagno di Cento Cavalli".

The oldest planted sweet chestnut in England is the Totworth Chestnut. In 1766 it measured 50 ft in circumference at five feet from the ground, had a stem 10 ft high at the fork, and had three limbs, one of which was 28.5 ft in girth. It was said to have been growing in King John's reign, and to have been '197 yards in compass'.

Throughout the ages, chestnuts have been an important food source for people as well as animals. Chestnuts have a remarkable nutritional composition that sets them apart from other nuts and makes them an outstanding food source, which can be a dietary staple. The nuts are about 50% water when fresh, which makes them highly perishable. They contain complex carbohydrate, are low in protein (about 5%), are very low in fat (about 1%), have reasonable quantities of vitamin C and potassium, are very low in sodium and are free of gluten, oil and cholesterol (Klinac, undated). The protein is high quality (comparable to eggs), and is easily assimilated by the human body.

For much of the last century world-wide production has steadily declined, due to disease, alternative land use and population pressure. For example, France grew nearly 400,000 tonnes of chestnuts at the beginning of the century, but by the 1960s this had dropped to 45,000 tonnes, by the 1980s to 25,000 tonnes and was only 11,000 tonnes in 1995. Despite a roughly 85% drop in production this century, Italy remains the largest European producer, and is the world's largest exporter of processed nuts and the associated peeling and processing technology.

China is the largest producer of chestnuts, but their total production and consumption is difficult to measure. Traditional production is based upon some 50 cultivars of the Chinese chestnut, but newer plantings by Japanese joint-ventures of C. crenata hybrids have been made. These nuts are cut by hand in a special way, before export to Japan. Cutting is labour intensive.

In addition to their use fresh, significant quantities of nuts are processed - canned, frozen, made into paste, etc. Many of these products command premium prices.

As well as the nuts, chestnut trees produce excellent timber, which has been widely used for many purposes. In particular, it is ground durable, making it suitable for use as posts. In Europe it is coppiced for poles - there were still 125,000ha of coppice woodlands being maintained in the south of England in 1969. The timber resembles oak, but is lighter and more easily worked. Scarcity has elevated the timber to a more sought after resource than it once was, when it was described as "never being a pretentious choice of glamorous woodworking - it was a plebeian wood, a cheap and plentiful performer of common tasks and often found as a secondary wood in the finest furniture".

The American chestnut was one of the most important trees in the eastern hardwood forests until the late nineteenth century, making up to 25 percent of the forest. It was used for virtually everything - telegraph poles, railroad ties, heavy construction, shingles, panelling, fine furniture, musical instruments and even pulp and plywood. In addition, the chestnut was America's major source of tannin for tanning leather. However, by 1950, the chestnut was essentially eliminated as a forest tree in North America, having succumbed to chestnut blight, which had been noticed first near New York in 1904.