Spanish chestnut

Sweet Chestnut
Sweet Chestnut fruit
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Fagales Family: Fagaceae Genus: Castanea Species: C. sativa
Binomial name
Castanea sativa Mill.

The Sweet Chestnut (Castanea sativa, family Fagaceae), also known as the Spanish Chestnut, Portuguese Chestnut or European chestnut, is a species of chestnut originally native to southeastern Europe and Asia Minor.

Growth

It is a medium-sized to large deciduous tree attaining a height of 20-35 m with a trunk often 2 m in diameter. The oblong-lanceolate, boldly toothed leaves are 16-28 cm long and 5-9 cm broad.

The flowers of both sexes are borne in 10-20 cm long, upright catkins, the male flowers in the upper part and female flowers in the lower part. They appear in late June to July, and by autumn, the female flowers develop into spiny cupules containing 3-7 brownish nuts that are shed during October. Some species ("Marron de Lyon, Paragon' and some hybrids) produce only 1 large nut, rather than the average 2 to 4 nuts of edible size.

The bark often has a net-shaped (retiform) pattern with deep furrows or fissures running spirally in both directions up the trunk.

The tree requires a mild climate and adequate moisture for good growth and a good nut harvest. Its year-growth (but not the rest of the tree)^[1] is sensitive to late spring and early autumn frosts, and is intolerant of lime. Under forest conditions it will tolerate moderate shade well.

Uses

Sweet Chestnut thousand of years old in Levie (Corsica).

Sweet Chestnut is widely cultivated for its edible seeds, also called nuts. As early as Roman times it was introduced into more northerly regions, and later was also cultivated in monastery gardens by monks. Today, centuries-old specimens may be found in Great Britain and the whole of central, western and southern Europe. They are widely popular in Turkey, Portugal, France, Hungary, Italy, Croatia, Bosnia and particularly in Corsica.

The raw nuts, with their pithy skin around the seed, are somewhat astringent. That skin can be relatively easily removed by quickly blanching the nuts after having made a cross slit at the tufted end.^[2] Once cooked they become delicious, developing, when roasted, a sweet flavour and floury texture not unlike sweet potato. The cooked nuts can be used by confectioners, puddings, desserts and cakes or eaten roasted. They are used for flour, bread making, a cereal substitute, coffee substitute, a thickener in soups and other cookery uses, as well as for fattening stock. A sugar can be extracted from it.^[1] The Corsican variety of polenta (called pulenta) is made with sweet chestnut flour. A local variety of Corsican beer also uses chestnuts. An easy way for peeling them is given here.

Leaves infusions are used in respiratory diseases and are a popular remedy for whooping cough.^[1]A hair shampoo can be made from infusing leaves and fruit husks.^[1]

This tree responds very well to coppicing, which is still practiced in Britain, and produces a good crop of tannin-rich wood every twelve to thirty years, depending on intended use and local growth rate. The tannin renders the young growing wood durable and resistant to outdoor use, thus suitable for posts, fencing or stakes.^[3] The wood is of light colour, hard and strong. It is also used to make furniture, barrels (sometimes used to age balsamic vinegar), and roof beams notably in southern Europe (for example in houses of the Alpujarra, Spain, in southern France and elsewhere). Due to older wood's tendency to split and warp badly, and acquiring a certain brittleness, it is not frequently used in large pieces. It is also a good fuel, though not favoured for open fires as it tends to spit.^[1]

Tannin is found in the following proportions on a 10% moisture basis: bark (6.8%), wood (13.4%), seed husks (10 - 13%). The leaves also contain tannin.^[1]

A tree grown from seed may take twenty years or more before it bears fruits, but a grafted cultivar such as 'Marron de Lyon' or 'Paragon' may start production within five years of being planted. Both cultivars bear fruits with a single large kernel, rather than an average of two to four smaller kernels.^[1]

Gallery

Sweet Chestnut, from Thomé, Flora von Deutschland, Österreich und der Schweiz, 1885	Sweet Chestnut on forest floor		Castanea sativa
		Sweet Chestnut tree	Middle Rhine Valley, Germany
Retiform bark	Ancient Sweet Chestnut coppice, Banstead Woods, Surrey, UK	A sweet chestnut forest in Ticino, Switzerland	Sweet Chestnut in Morlanwelz (Belgium)
Sweet Chestnut tree at Kew Gardens, London	Large Castanea Sativa

See also

• American chestnut
• Chinese chestnut
• Recalcitrant seed

References

Wikimedia Commons has media related to: Castanea sativa

1. ^ ^{a b c d e f g} “Plants For A Future” (PFAF http://www.pfaf.org/database/plants.php?Castanea+sativa and book.
2. ^ http://hedgewizardsdiary.blogspot.com/2006/10/peeling-chestnuts-easy-way-chestnuts.html an easy way of peeling the pellicle, or pithy skin.
3. ^ Oleg Polunin. Trees and Bushes of Britain and Europe. Ed Paladin, 1973, pp. 51, 188 and 195).

• Flora Europaea: Castanea sativa
• Rushforth, K. (1999). Trees of Britain and Europe. HarperCollins ISBN 0-00-220013-9.
• http://www.fao.org/DOCREP/006/AD235E/ad235e00.htm#Contents
• http://cesonoma.ucdavis.edu/hortic/pdf/chestnut_99.pdf