TREE OF THE MONTH - DECEMBER 2016 SWEET CHESTNUT

A work of art: roast chestnuts for sale in Italy- image by By Lucinao (Flickr) via Wikimedia Commons

A sailor's wife had chestnuts in her lap,
And mounched and mounched and mounched.
'Give me,' quoth I.
'Aroint thee, witch!'
the rump-fed ronyon cries.

from Macbeth

Seasons Greetings! The obvious choice for December's Tree of the Month was the Christmas Tree, but for me roast chestnuts are such an essential part of Christmas festivities that this month it simply had to be the Sweet or Spanish Chestnut. I first tasted roast chestnuts many years ago at a Victorian Evening in my home town. It was a crisp cold December night and there was a small crowd gathering around the heat of the vendor's brazier, their breaths frozen clouds. Being curious, I handed over what was then a lot of money - a princely 50 pence - and in return I was handed an inconceivably small paper bag, little bigger than a matchbox, containing just three chestnuts. Feeling somewhat disgruntled, I headed down the street peeling one as I went. But then I popped it in my mouth... and I was in heaven. Now I knew what Nat King Cole was singing about! In 1662 Evelyn spoke of them as 'delicacies for princes and a lusty and masculine food for rusticks, and able to make women well-complexioned,' and then lamented that in England they are chiefly given to swine...but pigs industrially fed on them in Spain and Corsica also produce the caviar of the ham world - Jamon Iberico. I still regard roast chestnuts and chestnut stuffing as one of the highlights of Christmas and for that reason December's Tree of the Month 2016 must be the Sweet Chestnut:

Sweet Chestnut (Castanea sativa) is a member of the Fagaceae family - all have fruits in the form of a nut either enclosed within a spiny or scaly capsule or held like an egg in a cup. The commonest native trees of the family are Oak and Beech, but Sweet Chestnut has been here for some 2000 years and might be considered an honorary native. In fact it was long thought to be a native and the suggestion that it was not sparked some controversy at the Royal Society in 1769, the arguments that it was native being perfectly sound at the time. The earliest written record is in the Forest of Dean where Henry II granted the tithe of Chestnuts to Flaxley Abbey and in the New Forest there was a boscus castanearis in the 14th century. But a clue to the tree not being native is the relatively little folklore and superstition attached to it - showing that much folklore derives from pagan times. Even so, it was only with the advent of pollen analysis that it was finally shown to be an introduction.

Image by Andrejj (Own work)(http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons

Originally from Mediterranean coastal regions extending eastwards to Asia Minor and the Caucasus, it was introduced by the Romans, probably for the nuts, which could be ground into flour, rather than timber - the nuts being very rich in carbohydrate of which there is little in an Edible Dormouse or other such Roman delicacy (although grains now provide humans with half our energy, in pre-agriculture days nuts are likely to have been the staple, their legacy surviving in regional cuisine - pistachio, walnut, cashew and almond in Middle Eastern cooking, hazel and chestnut further north, walnut, hickory and pecan in the Americas, coconut of India and the Pacific, macadamia of Australia etc....but I digress).

Magnificent ancient Sweet Chestnut at Canford School, Dorset - Image by Yours Truly - July 2016

Sweet Chestnut can grow to 100 ft or more and live to a great age, developing enormous trunks in the process - as in the above pictured impressive tree at Canford School in Dorset. Even larger is the famous Tortworth Chestnut in Gloucestershire, which I must visit, already described as a tree of legendary antiquity in 1706. Its subsiding branches have now taken root to develop 17 secondary trunks that form a 'wood' 30 yards across, complete with bluebells, dog's mercury, lesser celandine and garlic growing beneath. And even bigger still, which I really must visit if I can ever afford it, is the Hundred Horse Chestnut growing on Mt Etna which had a stem girth of 190 ft when measured in 1780. Confusingly, the Hundred Horse Chestnut is a Sweet Chestnut, not a Horse Chestnut, but is so called as it is said to have sheltered Queen Guivanna and her entourage of 100 knights when they were caught in a storm. The tree has now split into multiple stems and is fenced. A larger tree on Mt Etna died, reportedly succumbing to the repeated cutting of branches to fuel the fires to roast its chestnuts. That's killing the goose....and having no stuffing.

Hundred Horse Chestnut by Jean Houel (1735 - 1813)

Chestnut timber is much like Oak in appearance but is faster growing with more pronounced medullary rays (radial ribbons in the grain). It is very durable and will last longer than Oak in the ground making it ideal for posts and fencing. Larger timber can be used in building but once over about a foot and a half in diameter it is increasingly prone to a spiral grain and 'shake' - the splitting between annual rings or radially. It has therefore been more frequently used for cleft pale fencing, stakes, thatcher's pins and hop poles and managed by coppicing on a 9-16 year cycle. Its use as hop poles might partly explain its stronghold in the ancient woods of the home of brewing - Kent. Larger timber was once thought to have been used in buildings like Westminster Hall and Kings College Chapel, Cambridge - but these have since been shown to be Oak. Oliver Rackham did find it used at the 16th century Palace of Fontainbleau, where the medullary rays had been cunningly painted out to more closely resemble Oak. Was this a sneaky French contractor skimping on the specification and pocketing the difference? Sacre bleu !

Like a Flamenco dancer's skirt, the deep fissures of the bark often spiral up the trunk - a clue to the spiral grained timber beneath. Image By OliBac from FRANCE [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

Leaves and flowers - July

The leaves, which are relatively insect resistant,  are large, narrow and glossy, somewhat leathery in texture, 7 to 9 inches in length, about 2.5 inches wide, tapering to a point at each end. The deep mid-rib gives rise to side veins, each a valley ending in a saw-tooth point at the leaf margin, ideal for making 'fishbones' - the careful tearing out the soft leaf tissue to leave the skeleton. The leaves remain on the trees late in autumn, turning to a golden colour before a coppery brown. They are very efficient with less than 1% of light wavelengths useful for photosynthesis passing through, meaning little can grow well beneath a dense canopy. They are the only part of the tree listed by Maud Grieve's Modern Herbal (1931) as having a medicinal use - an infusion made from steeping dried leaves in boiling water being used to treat 'paroxysmal and convulsive coughs, such as whooping-cough, and other irritable and excitable conditions of the respiratory organs'.

Tree in flower in July

Magnified flower

The tree flowers in July, becoming cloaked in pale yellow catkins. These apparently present the only downside of the tree, many writers referring to the scent as sickly and unpleasant - though I don't personally find it so. Some catkins are entirely male, while shorter catkins have female flowers at the base from which the nuts develop, enclosed in prickly burs, becoming full sized within 4 months.

Prickly burs enclose the nuts

Castanea sativa 'Albo-marginata' - Canford

The stately proportions of the tree has meant that, as well as being valued for underwood and its fruit, it has been widely planted in parks, large gardens and avenues, making magnificent landscape features. A number of ornamental varieties are cultivated - the most commonly encountered being 'Albo-marginata' and 'Aureo-marginta' which have white and yellow edged leaves respectively.

Sweet Chestnut is sadly vulnerable to 'Chestnut Blight' a disease that decimated the American Chestnut (Castanea dentata). Caused by a fungus, Cryphonectria parasitica, the disease acts much like Dutch Elm disease, rapidly killing the tree but leaving the roots alive to resprout and grow, only for the disease to kill again when the tree reaches a certain size - and so on ad infinitum. The disease was imported to America between 1882 and 1904 on Asian Chestnuts and within 20 to 30 years it had killed 99.9% (about 3.5 billion) of the American Chestnuts in its native range of the Appalachian mountains, destroying it as a commercial crop. Squirrel populations crashed and seven species of moth living on the American Chestnut are now extinct. At about the same time it was first noted in Europe - but here there is some hope because in several parts of Europe some infected trees appear to have recovered. This has been associated with less virulent strains of the fungus that are thought to be infected with a virus that appears to have reduced the severity of the disease when used as a biological control. The disease was identified in 2007 in Warwickshire and again just this year in Kent. In both cases the trees had been imported from infected areas and planted here. The trees were destroyed and surrounding areas surveyed, but unfortunately they had been in the ground for four and seven years respectively before the disease was identified. Since 2013 imports of plants or seeds must have 'passports' to show they are not from an infected area and that timber has been fumigated or kiln dried. (Feb 2017 update: The Plant Health (Sweet Chestnut Blight) (England) Order 2017 ( http://www.legislation.gov.uk/uksi/2017/178/contents/made ) came into force February 2017. It controls the movement of Sweet Chestnut material within certain distances of 'demarcated areas'. There are currently two demarcated areas in Devon. Full details here: https://www.gov.uk/guidance/plant-health-controls#quarantine-pestsor http://www.forestry.gov.uk/chestnutblight ) 

Another potential piece of bad news for the Sweet Chestnut is the appearance of the Oriental Chestnut Gall Wasp (OCGW) in a Kent woodland in 2015 - and later on some trees in a single street in St Albans, Hertfordshire. The wasps don't sting or bite but, although not as devastating as the Blight, the larvae can weaken trees if infestations are heavy. The wasps are tiny and you would be unlikely to notice them, but the galls which form on leaves, leaf stalks and buds are a sure sign. The wasp is a quarantine pest giving plant health authorities powers to take action to try to control or eradicate it. You should report sightings to the Forestry Commission - click here .

Leaf gall - By AnRo0002 (Own work) [CC0], via Wikimedia Commons

But enough disease doom and gloom - it's nearly Christmas! Why not get a head start by preparing the stuffing. It will freeze until needed. Simply fry chopped onion, bacon and the turkey's liver in butter. Place in a bowl and add minced pork, plenty of chopped cooked chestnuts, parsley, thyme, mace, salt and pepper. Mix well and whop it in the bird. Happy days! Happy Christmas!

Stuff it! - image by Mark Miller (Own work) via Wikimedia Commons

sources:
Bean W. J Trees & Shrubs Hardy in the British Isles 8th Ed. Forestry.gov.uk - Chestnut Blight. Grieves M, A Modern Herbal, 1931. Johnson H, Trees 1973. Mabey R, Flora Britannica, 1996. More D & White J, Cassell's Trees, 2003. Rackham O. Ancient Woodland (2003 ed); Woodlands, 2006. Smith, D, Delia's Happy Christmas. Tudge, C. The Secret Life of Trees. Thomas P & Packham J, Ecology of Woodlands & Forests, 2007. Wikipedia. Wikimedia Commons