Superb Sweet Chestnut Trees
The sweet chestnut is a large, handsome tree with fine leaves and, and distinctive twisting bark. But its crowning glory is its masses of shiny dark brown autumn fruits.
We probably have the Romans to thank for introducing the sweet chestnut to the British Isles. It is a native of Asia Minor and eastern Mediterranean countries such as Greece and Yugoslavia. The Romans spread it through-out Europe because the nuts were an important source of food to them. The first evidence of the presence of sweet chestnut in Britain is as charcoal fragments excavated from sites of Roman forts and villas. It does not readily establish itself in the wild and most of the specimens you see have been planted.
The sweet chestnut is not related to the horse chestnut, and it would be difficult to confuse the two: in fact, it belongs to the same family as the oak and beech, and rivals them in grandeur. It grows up to become a massive tree reaching 30m (100ft) high, its huge trunk extending right up into the crown and sending out contorted limbs to form a broad leafy dome.
The sweet chestnut does best on deep, well-drained soils but tends to avoid chalk and limestone. It is most abundant in south-eastern England but it is widely distributed elsewhere, although it is less common in northern England. Scotland and Ireland. It can be found in woods and plantations and has also been widely planted as an ornamental tree in parks and gardens.
The winter twigs are reddish-brown and bear plump buds, about 5mm (1/5in) long, set on little ledges spaced rather irregularly along the shaft of the twig. The tree breaks into leaf towards the end of April or early in May. The fully expanded leaves are 10-25cm (4-10in) long and a rich glossy green. A short leaf stalk supports the spear-shaped leaf blade. The edges of which are cut into long teeth where the prominent veins reach the leaf margin.
Both male and female flowers are set on dangling catkins up to 15cm (6in) long, which sprout from the base of the leafstalks on the younger shoots. The yellow male flowers, consisting of a dense tuft of stamens, are much more numerous than the females which are confined to the upper part of the catkin near where it joins the shoot. The greenish female flowers are in groups of three set in a small prickly collar (cupule). Although wind pollination does take place, the pleasant scent from the catkins attracts insects which collect and feed on the pollen, some of which they unwittingly transfer to the female flowers.
After fertilisation the cupule grows around the ovary in which the seeds develop and forms the familiar green ‘hedge-hog’ case. During October, when the nuts are ripe, the spiny coat splits open, the four lobes peel back, revealing up to three glossy brown nuts packed snugly inside. The nuts are roughly triangular in shape, flattened on the side which lies next to another nut. A tuft of silvery hairs at the point indicates the remains of the stigmas.
The sweet chestnut, with its exceptionally large seeds, cannot be dispersed by the wind or by many animals. However, some animals – notably squirrels and jays – collect and bury them as an insurance against winter shortages of other fruits. Because most animal memories are no match for their thriftiness, many caches are not relocated, and so for the sweet chestnut these creatures are important ditributors and planters in the wild.
Crunchy golden leaves
While the nuts are dropping from the trees the leaves acquire their autumn hues, paling first to yellow and then darkening to gold before dropping. The fallen leaves form a deep carpet beneath the tree and this rustles loudly underfoot because they remain stiff and dry-not soggy and shrivelled like those of so many other trees.
Although mature sweet chestnuts yield a large volume of timber, the wood is not as useful as oak because cracks tend to appear during seasoning. This condition, known as ‘shakes’, severely limits the size of beams or length of planks that can be extracted from the bole. However, the timber is durable out of doors and even under-ground – it has been used for making coffins.
The sweet chestnut is one of the few European trees that matches the oak for longevity. Its normal span is about 500 years but many specimens exceed this. In old age the tree becomes grotesquely misshapen with a gigantic gnarled trunk and huge twisted limbs so heavy they may touch the ground.