My friends were married in the ancient yew forest at Kingley Vale. Their wedding rings were made of yew too – circular symbols of infinite love made from England’s most enduring tree. We revellers gathered on a September evening and I’ve never forgotten the silvery light in the valley, nor the feeling of pilgrimage as I walked there with my young sons to sit in the crook of a yew’s lowered branch and witness whispered oaths.

When I went back the other day, a floating Walker’s crisp packet (Ready Salted, relic of some recent DofE adventure) did not detract from Kingley Vale’s witchy power. Park up and walk just over a kilometre, in the early morning if you can, before others arrive. In the evening you may be too scared, for these old yews are alive, their sinewy, gnarled elbows and fingers and knees stretching across the path to reach each other. And perhaps grab you.

It is Shakespeare’s three witches in Macbeth who concoct a poisonous brew including ‘slips of yew silvered in the moon’s eclipse’, and it is true that every single part of the yew – bark, resin, leaf and seed – produces taxine alkaloids, which will kill a sheep or a cow or a horse or a human being. Only the fleshy red berry of the yew – the aril – is safe to eat, as long as you spit out the pip. It is an elegant evolutionary trick: wrapping a poisonous seed in a sweet red aril irresistible to birds, who carry it across the countryside before depositing it unharmed.

King Edward I recognised what birds already knew: yew was uniquely useful. Strong yet flexible, it became the wood of the English longbow, so prized that by the late 13th century England had exhausted its own supplies and was importing yew staves from Europe. The longbow reached its deadly zenith at Agincourt before eventually giving way to gunpowder.

We don’t have any early longbows, only accounts from near contemporaries such as Gaston Fébus, Count of Foix (1388), but we know that, by statute in 1472, anyone importing goods by ship from Europe was obliged by law to bring four yew bow staves for every ‘tun’ (a unit of liquid volume used for measuring wine, oil or honey in barrels). We know longbows were still in use in Henry VIII’s time, for when his ship Mary Rose (which was lost in 1545) was recovered from the Solent’s seabed off Portsmouth in 1982, archaeologists found on board 37 yew bows and 3,500 arrows made variously of ash, beech and hazel.

Another longstanding theory is that yews – on account of being poisonous to animals – were planted in churchyards to keep cattle, sheep and horses from grazing over graves, and therefore became associated with ghosts and ghouls. Their dark presence and long shadows only exaggerate the gruesome reputation of the yew. As you will notice, if you frequent graveyards, the tradition of planting yews near churches continues to this day.

However, yews have been planted on sacred sites long before Christianity. In AD 601, Pope Gregory the Great suggested churches be built on places of pagan worship, where there were often yews already. The yew became associated with Christian ritual, but it had long symbolised death and the journey to the next life. The yew was sacred to Hecate, the Greek goddess of death and witchcraft, and the Celtic druids also saw – and still see – the yew as sacred.

This symbolic power may be because of the yew’s astonishing ability to regenerate itself. As the yew ages, its ancient branches lower themselves to the ground and where the lowered branches touch the earth, new trees grow, still connected to the original trunk. You can see this in Kingley Vale – where there are yews over 2,000 years old – and at other sites in Sussex, such as Wilmington Church, where the 1,600-year-old yew, which pre-dates the 12th-century church, is hollow at its core but surrounded by its progeny, all living and breathing together through the same roots.

Despite this capacity for rebirth, Alfred Lord Tennyson called the yew a ‘sullen tree’ in his 1850 poem In Memoriam, a lament for his dead friend Arthur Henry Hallam, which opens:

Old Yew, which graspest at the stones That name the under-lying dead,

Thy fibres net the dreamless head, Thy roots are wrapt about the bones…

Nor branding summer suns avail

To touch thy thousand years of gloom.

A thousand years of gloom! It’s no surprise that In Memoriam became Queen Victoria’s favourite poem, though Tennyson’s melancholy yew is a long way from the tree’s older pagan symbolism of renewal and rebirth. Christianity absorbed many of those earlier associations, but the Victorians largely preferred the yew as an emblem of mourning rather than regeneration. Yet compounds derived from the yew have also become life-saving medicines. Taxanes, developed from chemicals found in yews, are used in chemotherapy to treat breast, ovarian and lung cancers.

I have planted a yew hedge here at home. It provokes shivers and comments like, ‘How grim, it isn’t a churchyard!’ or ‘What a dull hedge, where’s the life in that?’ Little do they know. I celebrate the yew’s evergreen steadfastness and its resilience, even on chalk. I wait for its acid-green fresh growth and feel its strength and the possibility of its eternal life. The ancient yews at Kingley Vale have witnessed many battles and ceremonies. Those yews are the wise bystanders who will endure long after we have lived our small lives. That makes me smile.