Chestnuts (Castanea), are a genus of eight or nine species of trees and shrubs, including the chinkapins, in the beech family Fagaceae, native to warm temperate regions of the Northern Hemisphere.
The name chestnut refers to the edible nuts produced by these trees. Most are large trees to 20-40 m tall, but some species (the chinkapins) are smaller, often shrubby. All are deciduous.
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 (Bean 1970). The fruit is a spiny cupule 5-11 cm diameter, containing one to seven nuts. Chestnut trees thrive on acidic soils, such as soils derived from granite or schist, and do not grow well on alkaline soils such as limestone. When wanting to grow chestnut trees on such soils, the practice was to graft them onto oak rootstocks.
The nuts are an important food crop in eastern Asia as well as southern Europe, southwestern Asia, and also in eastern North America. Since the Jomon era in prehistoric times, chestnuts have been ground into flour and chestnut breads and sweets were eaten here in Japan. Chestnut-based recipes and sweets are still traditional dishes of autumn today. 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 wood is similar to oak wood in being decorative and very durable. It is difficult to obtain large size 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 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.
Come October, it gets really hard to resist the smell of roasted chestnuts from the chestnut cart. A 5-minute walk away from my home however, are these chestnut groves which in season have the most marvellous large chestnuts hanging from the trees.
In her Japan Times column, Linda Inoki writes of the many uses of chestnuts:
“Stepping on a prickly chestnut in straw sandals would be painful, but the seeds of the kuri (Japanese chestnut tree; Castanea crenata ) are a welcome sign of autumn. They turn up in paintings, designs and flower arrangements and in sweetmeats and seasonal dishes such as kuri-gohan (chestnut rice). Japanese people have cultivated chestnuts since ancient times, and in some areas they were a staple before rice cultivation became widespread. The trees bloom in early summer, producing feathery catkins of fragrant, cream-colored flowers that attract bees. By autumn, the few female flowers at the base of the catkin develop into bright-green burs. The spines protect the seeds until they are ripe, when the burs split open, typically revealing three seeds. Wild trees can grow to 17 meters tall, but in orchards they are kept to a more manageable height. These deciduous trees with slender, toothed leaves are members of the beech family, though unlike the beech itself, their bark is ridged. Their hard timber was traditionally valued for making boats and barrels, but more recently was used for railway sleepers.” Source: Japan Times
Note: neither the horse chestnut (family Sapindaceae) nor the water chestnut (family Cyperaceae) is closely related to the chestnut, though both are so named for producing similar nuts.