The Yew Trees of Kingsley Vale
Britain probably boasts the finest natural yew woodland in Europe, Kingsley Vale in the South Downs of Sussex.
Far away from the main road on the South Downs of Sussex lies a great valley a mile long and half a mile wide. This Roman amphitheatre shaped valley faces south to the sea and has slopes as steep as any Scottish mountain. Nearly 20,000 yew trees, mainly gnarled and twisted with age into fantastic shapes, all crowd into half a square mile.
The valley's name is Kingsley Vale which means, burial place of kings. In 1904 a writer described the forest as grave and silent- transformed at dusk into a sinister and fantastic forest, a home for witchcraft and unquiet spirits. Even today, many people do not venture into the forest at night.
Ice Age carving
The symmetrical horse-shaped valley of kings the Vale was carved out 10,000 years ago during the last Ice Age when glaciers moving southward swept away the top layer of soils down towards the sea, leaving chalk bedrock exposed on the slopes behind.
Eventually, prehistoric people cultivated the valley floor leaving behind many marks of his occupation – small field banks can still be seen as a pattern on a chest board, as can earth banks with which he fortified to the hilltop against invaders. At the crest of the valley are domed tombs of early people. These may well be the kings that gave the Vale its name.
By the 16th century, sheep were grazing the downs in thousands, their close nibbling creating a carpet of turf composed of dozens of different species of small herbs and grass is cold chalk turf. A sheep fair was held in the Vale every Midsummer in the 1800s. Trees and shrubs could not grow in these conditions of grazing animals, and even rabbits have played their part.
Legend has it that the men of Chichester planted this Grove to commemorate a battle fought and won against Viking Raiders. The bronze-age tumuli on the hill may be the Viking kings' burial places.
The Yew Tree life cycle
Twenty original yew trees gave rise to the thousands of yews to be found on the slopes of Kingsley Vale today. Female yew trees can produce fertile seeds aged 25 years and continue for several centuries.
The fruits of the Yew Tree consist of a stony pip enclosed within a fleshly red aril. They start to develop as soon as fertilisation takes place in late February. The pollination of the trees is sometimes a spectacular phenomenon. It usually occurs on a dry, windy afternoon when gusts of wind-down of the male trees and pull away dense clouds of yellow pollen from the flowers. Sometimes much of this pollen blows away to form a plume-like the smoke of a bonfire.
'In Kingsley Vale, the male yew trees outnumber the female yew trees, so pollination occurs quickly. Once this happens, the green female flowers, previously no bigger than a pinhead, are fertilised and start to swell, while the male flowers fall and carpet the ground beneath.
Food for wildlife
The first fruits are ripe by July, but it's not until October that the crops are complete. Mistle thrushes are the first creatures to begin feeding on the glutinous jelly of the arils. Later fieldfares, redwings and song thrushes in mixed flocks arrive to feed, and native blackbirds join in as well. Unfortunately, these birds appear to extract little nutrition from the arils, which pass through very quickly.
Other animals, such as foxes, feed on the arils, almost exclusively for a few weeks, passing 250 pips in a single dropping. Then, badgers eat the whole fruit and seeds.
Struggle for survival
With so many animals feeding on the fruits, the seeds are distributed very effectively through the surrounding countryside. However, it does not follow that a yew tree would develop. A seed takes 18 months to germinate if not eaten by mice. The seedling, which resembles a tiny palm tree, may last only a few months before being scorched by the sun or eaten by herbivores such as fallow deer.
Survivors perhaps landed amongst prickly bushes such as hawthorn or juniper and grew safe from predation. On steep slopes of the valley, these so-called 'nurse shrubs' spread fairly rapidly during periods when sheep grazing becomes less intense for a few years due perhaps to temporary economic decline or war. One part of the wooded valley provided a firing range during WW1, and there is a much younger area that dates back to WW2.
The arrival of deer in Kingsley Vale had stopped the expansion of the Yew Tree wood when in 1973, forty fallow deer took up residence in the Vale when the trees in nearby woodland grew above their browsing line. These deer feed on the young tree foliage, sometimes exclusively so and at the other time supplemented by local farm crops. The result is that many yew trees shorter than 1.5 metres has not been allowed to grow any higher, and the deer eat most seedlings as soon as they germinate. Only those yew trees protected by hawthorns are growing freely. The deer seemed to be suffering no ill effect from their diet and must be immune to the poison in yew leaves that quickly kill most other creatures, including humans.
Sheep still help to control the spread of yew trees; they are grazing some 35 hectares of chalk grassland, eating the yew seedlings with no ill effects.
Kinsley Vale is continually changing. Since the mid-1970s, thousands of trees have been lost, most by falling over through storm damage or route slippage. Where these gaps have occurred, heavy browsing has prevented the return of woodland. Instead, areas left bare are colonised by grasses and herbs, marking the beginning of a return to the chalk grassland vegetation that used to be there.