Ancient trees are rare. This country, however, is blessed with more ancient trees than anywhere else in northern Europe, and their presence tells us much about our past. Trees are deemed ancient according to species. A birch will obviously be deemed ancient before the longer-living oak, but ancient trees of any stripe exert a strong appeal; perhaps they fend off our mortality. Every day, it’s my good fortune to see a plane tree planted in 1680 that stands in the shadow of Ely cathedral. Judged one of our 50 greatest trees, it rises to a flourishing 114ft, and to stand beside the sinewy strength of its 26ft girth is strangely reassuring.

It is mere happenstance that we have this sumptuous legacy of ancient trees – a quirk of social history. In the United Kingdom, the aristocracy may have declined over the years, but it did not fall. As a consequence, vast landholdings have passed from generation to generation for centuries without being scarred by progress. For a tree to survive to a great age, it is imperative that it, too, is left undisturbed, and this symbiotic relationship between trees and artistos has worked wonders for arboreal longevity.

Jill Butler of the Woodland Trust pinpoints the moment in history when it all began. “The crème de la crème of the UK’s ancient tree sites are Windsor, the New Forest and Savernake,” she says. “They were William the Conqueror’s hunting grounds, which he protected by statute. To emulate William’s love of the chase, everyone wanted a deer park.” Their creation was set to continue for centuries, the concept of the deer park forming the basis of the romantic English landscape fostered by gardeners such as Humphry Repton, who incorporated mature trees and hedgerows into his designs.

The deer park at Baronscourt, Co Tyrone, was established by the eighth Earl of Abercorn. A gardener named James Broomfield began planting the park with clumps of oak, beech, laburnum and lime in 1746; the deer arrived five years later.

“We’ve been here since 1610,” reports the third Duke of Abercorn. “And the character of an estate is, I always believe, dominated by trees and water.” Experience tells him exactly what trees crave: “Minimum interference with nature,” he counsels, relating a family anecdote. “The eighth Earl of Abercorn was entertaining the local rector for lunch, and the eighth Earl was taciturn, and a bachelor. After lunch they had a walk outside and the rector said, ‘My lord, your trees are growing well.’” Our storyteller suppresses a laugh. “And the eighth Earl replied, ‘Sir, they have not much else to do.’”

Given the right conditions for regeneration, trees can almost live forever. One that is hollow and seemingly melting down into the earth to die can be alive and well: the living matter lies directly beneath the bark. Landowners, too, must balance the past with the future, and the Duke says: “Government departments in Northern Ireland are very sympathetic towards the maintenance of deer parks and, indeed, their reconstruction. It is the responsibility of every generation to continue planting.”

He follows his father’s 1945 scheme for hardwood planting and has also replaced parkland trees lost to Hurricane Debbie in 1961, and another savage storm in 1998. “We conserve and preserve. And cherish. What I love, and which grows extremely well in this part of the world, is birch, and also oak. We’ve got in front of the original Baronscourt family home two 1745 oaks, which are going strong. They are much loved, admired and appreciated – by the family, and visitors, too.”

In another part of the kingdom, Torquhil Campbell, 13th Duke of Argyll, learnt to love trees in the traditional way, by climbing them as a child. He was spoilt for choice at Inveraray. “There are so many here. We’re very, very lucky; plenty of options for children. There’s a wonderful old chestnut in the garden – just a magical tree.” His appreciation must be genetic, for there follows a compelling tale, in step with history, of one family’s commitment to the trees that give our landscape its distinctive character.

It can be traced back to the first Earl of Argyll’s move to Inveraray for, some 100 years later, in mapmaker Timothy Pont’s 1590 record of the area, there was clear evidence of trees beside the old Inveraray Castle, and along Glen Shira. A contemporary account of the seventh Earl’s (1575-1638) trees describes them as “verie prettilie sett and planted”. It was this Earl who introduced Spanish chestnut to the area, and the present Duke’s “magical tree” is one of a large number of this species on the estate; its girth measures 26ft, and it’s reckoned to be 350 years old.

The only Marquess of Argyll was responsible for three major avenues of trees, the third of which is the celebrated lime avenue planted around 1650 and radiating from the old castle. The new castle, begun in 1744, was aligned on this lime avenue for it commemorates the marquess’s role in bringing Charles II to Scotland in 1650 and, in 1651, placing the crown on the King’s head in the coronation ceremony in Scone. (Ten years later, Charles executed him for his previous allegiance to Cromwell.) Many of the original trees in the avenue survive today, plus necessary replacements.

In 1684, a daring raid on the ninth Earl’s tree nursery saw the Murrays of Atholl steal 34,000 trees. Landscaping was commissioned from William Boutcher by the 10th Earl, and many of Boutcher’s vistas exist today. In 1756 alone 19,657 specimens were planted, and a contemporary visitor recorded, “One could ride for three miles up Glen Shira through plantations.” A Liberal, the eighth Duke was an active politician and his guests frequently planted a tree at Inveraray. For both Gladstone and Dr Livingstone, it was a sweet chestnut, for the Earl of Shaftesbury, a maple. All survive.

When his son, the Marquess of Lorne, was governor general of Canada, he sent tree seeds back to Inveraray from British Columbia. Conifers thrive in Argyll’s rain and humidity, and some of the resulting giants today reach

48 metres. Cared for by five foresters and the Duke’s past and present factors, Peter Fair-weather and Andrew Montgomery, Inveraray’s historic trees face a rosy future. In time, the Argylls’ two young children will also climb them – “And they won’t be wearing hard hats and orange jackets,” says their father with a swipe at the Health & Safety loonies.

In West Sussex, a passionate new advocate has recently been recruited to the cause of ancient trees. The Duchess of Norfolk, wife of the 18th Duke, sings the praises of Ted Green, leading light of the Ancient Tree Forum. “Ted opens your eyes and makes you see how special these old trees are. I didn’t think we had any in the park because everything came down in the ’87 storm. And he said, ‘That looks fascinating…’ and there was a 500-year-old oak: incredible. The storm was the year I got married, and I never really knew the park before then. It was probably just as well. For people that did, it must have been terrible. But we’re replanting.”

Together with foresters Mark Aldridge and Tony Hart, and specialist tree surgeons, the Duke and Duchess grapple with the dilemma of retaining old trees in 1,000 acres of parkland and 40 acres of gardens, a public area classed as a high-use environment. “It’s so upsetting when the tree surgeons come along and say, ‘Oh, you’ve got to chop down these lovely trees…’ because of the insurance situation. Trees are what people are paying money to come here and see.” But Ted Green and Jill Butler have, she says, offered constructive solutions, and she whoops with delight at the prospect of ancient, gnarled horse chestnuts continuing to mount guard before an ancient building. “They’re right in front of our barbican drawbridge which is going on 1,000 years old.”

Away from a frenetic professional life, Viscount Blakenham is a past chairman of Kew Gardens’ trustees, the RSPB, and a farmer with 500 (give or take) mature and ancient trees on his land in East Anglia. He is also a romantic. “Old trees are magnificent,” he says. “Even in a wood, you quite often get two really old trees next door to each other rather like husband and wife standing together for perhaps centuries. I remember as a child climbing the trees overhanging an old chalk-pit here to look at the wildlife. We have lots of wonderful hedgerow oaks, and a couple of ancient woodlands.”

To qualify as ancient, woodland must exist without disturbance for 400 years, but more exciting still, Lord Blakenham’s land supports healthy elm trees. “Our farm is one of the few places in Britain that still has mature elms,” he says, “with some, reputedly, the largest in girth remaining in the UK. As a resource for propagation, they are unparalleled, as they’ve demonstrated a capacity to survive – although the science to understand it has yet to catch up. Fingers crossed, they will continue to survive. One tries to see they don’t come to any harm.

“The more you know about trees, the more you get out of them. As trees age, they become absolute havens for wildlife. Ancient trees support a micro-world of insects, beetles and fungi, and many of these species are rare and declining.” Lord Blakenham has planted 100 acres of mixed woodland on his farm over the past 20 years, and in their centenary year, local boy scouts boosted this acreage with commemorative trees.

“If you plant a tree as a child,” he says, “you will always come back and look at it, and the earlier it’s planted the better!”