Sweet Chestnut trees have become one of my favourite species over the last twenty years or so and I’m always drawn to look at them and of course to take their photographs. Until coming to live in North Wales I’d seen them only on walks around big Public Parks, Grand Gardens and in Arboretums, situations in which I might expect to find them, but here I’ve encountered them fairly frequently growing in wilder woodlands. There are three growing at different points along one of my regular trails around Bryn Euryn that stand out amongst the surrounding Oaks, Ash and Sycamores, and others in other woodlands and public gardens locally, some of which have been quite unexpected.

Researching this post I found that the ancient Sweet Chestnut at Bodnant Gardens was a nominee in the Woodland Trust’s annual Tree of the Year competition and that the winning tree in Wales for 2019 is the Old Sweet Chestnut of Pontypool, which confirmed that this was the perfect time to be putting the post together.

The Sweet Chestnut, or Castana sativa is native to mainly mountainous regions of southern Europe, western Asia and north Africa and is considered most likely to have been introduced into Britain by the Romans. But these beautiful trees have graced our islands for many centuries and are considered honorary natives as they behave similarly to native trees; they propagate themselves by seed and are able to maintain levels of wildlife biodiversity similar to that of native broadleaved trees such as the related oaks and beeches.

Etymology

English name(s): Sweet Chestnut, Spanish Chestnut Latin Name: Castana sativa Welsh name: Castanwydden Felys Family: Fagacaea

As the Sweet Chestnut is not a true native to Great Britain, there is very little mythology associated with it here, but the ancient Greeks dedicated the sweet chestnut to Zeus and its scientific botanical name Castanea comes from Castonis, a Town in Thessaly in Greece where the tree was grown for its nuts.

The Latin sativus is based on satus, meaning ‘sown’, perhaps implying the tree has been cultivated by humans. Also etymologically related is our native English ‘seed’.

The tree is commonly called the “Sweet Chestnut” to distinguish it from the Horse Chestnut Aesculus hippocastanum, to which it is only distantly related. Other common names include “Spanish Chestnut”, “Portuguese Chestnut” and “marron” (French for “chestnut”).

DESCRIPTION

Sweet Chestnuts have mostly straight trunks, easily recognised by their twisted rugged appearance and thick branches that start at a low height. Trees may reach heights of anything from 60 to 80 feet (20 to 30m) high and sometimes even higher; specimens of up to 110 feet (38m) have been recorded and they may live to an age of 500 to 600 years; cultivated individuals may even achieve a lifespan of 1000 years or more.  Some trees grow straight and attain great heights, particularly those in woodlands that have competition from other species, many others develop exceptionally broad trunks in relation to a lesser height and there are records from various parts of the country of trees with girths of over 25 feet (6m+).

BARK

A particularly distinctive characteristic is the tree’s beautifully textured bark, which develops deep evenly spaced fissures that spiral upwards from the base of the trunk. The fissures develop early on in the life of the tree and continue to thicken and widen as the tree ages. It is interesting that the fissures may spiral in either a left- or right-handed direction, and sometimes even both, with the fissures then creating a net-like pattern. The bark of the trees in my photographs below, both spiral to the right, that of the tree above, growing in Kew Gardens is spiralling to the left. (Being hugged by one of my granddaughters, aged two at the time.)

LEAVES

The leaves usually open out some time in April, they are large, sometimes as much as 10″ (25cm), mid to dark green in colour and slightly glossy. Sometimes aptly described as handsome, they are a simple lance-shape, are deeply indented and have large pronounced teeth evenly spaced around their margins.

I like the way the sun shines through them on bright summer days.

FLOWERS

The Sweet Chestnut tree is monoecious, meaning that although it requires both male and female females in order to reproduce, both are borne on the same tree. In Britain it is one of the last trees to bloom, with flowers usually appearing from mid to late July or sometimes even well into August. When they do appear the groups of flowers are very noticeable, held on drooping stems that are some 6-8 inches (16-20cm) long.

The long, creamy pale yellow catkins arise from the axils of the leaves: those growing from the lower axils bear only male flowers. Those growing from the upper leaf axils bear both male and female flowers – the males at the distal (far) ends of the axils and the female ones nearest the axils. Individual flowers are simple; the male flower has about 10 stamens that are surrounded by 5-6 sepals. Female flowers are borne in groups of 2-3, with each group surrounded by a scale capule. Each flower has a single ovary surrounded with several styles. Pollination may be either by insects or by wind.

FRUITS

Following fertilisation each ovary develops to form a nut. The capule also enlarges to form a thick strong green and very spiny covering that encloses the two or three developing nuts.

When they are ripe, the prickly capule splits and the brown edible nuts are exposed.

VALUE TO WILDLIFE

The flowers provide an important source of nectar and pollen for bees and other insects. Red squirrels eat the nuts and I’m sure Grey ones must do too. There are a number of micro-moths recorded that feed on the leaves and nuts.

SWEET CHESTNUTS AS FOOD

The trees were originally brought into Britain by the Romans with the intention of providing one of the fundamental staple foods of their armies’ traditional diet. (This was clearly a long-term plan; it can take 20 years for a tree to mature and bear fruit.) The nuts are high in carbohydrates, so high in calories. They would have been dried and ground into a versatile flour used to make polenta, porridge, bread and even pasta. In Italy today huge forests of Sweet Chestnut trees cover something like 400,000 acres of the country’s land, which are still grown and harvested for their fruits and continue to be widely used as a staple food in the same traditional ways and also as it is naturally sweet, to make biscuits and cakes.

As the flowers bloom so late there is not much time left in a typical British summer for the fruit to develop before conditions make it impossible. This is why Sweet Chestnuts that grow much further north than the Midlands seldom bear fruit. Here in Wales many of our trees do bear fruits, but the nuts are usually small compared to those that we import from mainland Europe, mainly the South of France and Italy. Our British nuts are equally edible, and it said that what our home-grown nuts lack in size they make up for in sweetness and flavour.

I wonder why they are not foraged as frequently now as they used to be? Some nuts may be taken and distributed by animals such as squirrels, but often they are simply left on the ground where they fell. Chestnuts roasted on an open fire have been a  winter delicacy in Britain for generations. Chestnut stuffing was a traditional part of the Christmas Turkey dinners, particularly in areas where the trees grow most prolifically and nuts were gathered as a welcome seasonal food item. They were also one of the original ‘street foods’. roasted on braziers and served up by vendors piping hot in paper cones. This tradition has largely faded out here, probably something to do with ‘health and safety, but it continues to thrive in other European countries, particularly Italy, Spain and Portugal, where many festivals are held during October and November to celebrate the year’s harvest.

TIMBER AND COMMERCIAL USES

Sweet Chestnut wood is a light brown in colour and very durable. It is similar in appearance to oak and is sometimes used as a substitute for it. Sweet Chestnut and Oak may easily be confused in the identification of old timber.

The main Chestnut area in Great Britain is concentrated in England, especially in the southern counties of Kent and Sussex, where extensive stands of commercial coppice, amounting to some 18,000 hectares were planted in the mid 19th century. Here Sweet chestnut trees continue to be grown commercially for the timber and to a lesser extent, the nut markets. Chestnut coppicing for the timber industry has been enjoying a revival in recent years and although these industries are small they are locally important, particularly in Kent. A well-maintained coppice can produce a good crop of tannin-rich wood every 12 to 30 years, depending on intended use and local growth rate.

The high tannin content of the wood makes the young growing wood durable and resistant to the elements, so is widely used outdoors as posts, piles, poles and Chestnut fence palings.

In other parts of mainland Europe the wood is 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) (Wikipaedia)

ANCIENT TREES – in ENGLAND

Sweet Chestnut trees are capable of living to a great age and there are some wonderfully huge and significant ancient specimens in England and Wales. Credited with being the oldest of them all is the village of Longhope in Gloucestershire. This county can also lay claim to the biggest of all, the famous Tortworth Chestnut. An immense mass of wood formed of contorted trunk and convoluted branches, the tree is very much alive. Side branches have collapsed over time, but where they have made contact with the ground, all have taken root and continuously send up new shoots. The original tree has become a small woodland in itself, extending more than 30 yards (28m) across that has Bluebells, Ramsons and Dog Mercury growing within it. The original tree is impossible to date, but a plaque installed on a fence states ” This tree is supposed to be six hundred years old – 1st January 1800. May Man still guard thy Venerable form From the Rude Blasts and Tempestuous Storm. Still mayest though Flourish through Succeeding time, And last, long Last, the Wonder of the Clime.”

ANCIENT TREES in WALES

Tree of the Year 2019: Old Sweet Chestnut of Pontypool

“This amazing sweet chestnut tree in Pontypool Park is around 400 years old. There are many other sweet chestnut trees in the park but from an ecological perspective, this one is the most interesting as it is hollow and you can walk inside it.
Over the centuries, many children would have centred their games around the tree, particularly for ‘hide and seek’ – even when everyone knew where they were!
These veteran trees – and especially this one – are a visible reminder of our heritage. The park was owned by the Hanbury family until it was given to the people of Pontypool in the early part of the 20th century.” (Woodland Trust)

The Three Sisters, Llanrhaeadr, Denbigh, Clwyd 

In North Wales, beside the Ruthin to Denbigh road, there once grew three enormous Sweet Chestnut trees that had sufficient significance to be marked on OS maps. These ancient trees, known locally as The Three Sisters were planted in the garden by three sisters, the three daughters of Sir William Salusbury. One of the trees died, the remains of one was left for many years as a pile of dead wood, and one is clinging on to life, holding its own. This surviving Sister still inhabits the garden of the house now named after these trees (formerly the park of Bachymbyd). The girth of the tree was reported in 1781 by Pennant, and from that measurement it is estimated that it is now around 500 years old. It has a short bole and is hollow and open on one side. It was taped at its narrowest point between the burrs for the Ancient Tree Hunt in 2007. The girth of the tree, measured at a height of 90 cm, is about 42 feet (12.70 m): (2007, Ancient Tree Hunt (Rob McBride)). Its height is not known.

Bodnant Garden, Conwy Valley, Clwyd

As previously mentioned, the grand old Sweet Chestnut that graces the Top Lawn of Bodnant Garden was also a contender for the Wales Tree of the Year 2019 competition. One of the oldest at Bodnant Garden, this tree is a remnant of its early, Georgian past.
John Forbes built the original hall in 1782 and created a parkland around it in the Landscape style of the day, planting native trees.

It has a gnarled, many-legged trunk since the main stem was blown out at some point in the past by a lightening strike causing the trunk to split. Over time several of the larger branches have layered themselves upon the lawn, giving the tree ‘legs’ and it is known as a walking tree.

“Having lost her top many decades ago, she started to ‘walk’ northwards. Beaten back by strong winds and chainsaws, she is now intent on a south-westerly route. A truly ‘walking tree’, she appears almost Elephantine without foliage, placing her trunk where she wants to go next. She has already layered daughters which are layering their own offspring and, given chance, they will layer theirs.” (gardener Dave Larter)

THREATS

Sweet chestnut blight is a destructive disease of Sweet Chestnut trees that is caused by the ascomycete fungus Cryphonectria parasitica. First identified in Britain in 2011 in Warwickshire, by 2018 the disease was identified at 37 sites in England and associated with trees imported before the introduction of the UK Protected Zone in 2014. This year a further small number of new outbreak sites were detected in London, West Sussex and Cornwall during surveys. Sweet Chestnut woodland is not widely distributed in the UK, mostly in England amounting to perhaps 2% of England’s wood cover and located mainly in the south, so any impact would be largely regionally and locally felt.

C. parasitica infection is usually fatal to European and North American Sweet Chestnut trees. It devastated forests in eastern USA during the first half of the 20th century, killing an estimated 3.5 billion trees after it was accidentally introduced from Asia, probably during the 19th century. Although losses have not been on the same scale, Sweet Chestnut blight has spread steadily throughout much of Europe, and tree losses have been regionally significant.

References: Books: Meetings with Remarkable Trees – Thomas Pakenham; Flora Brittanica – Richard Mabey Websites: Woodland Trust; Wikipaedia