Oaks – Natural histories of extraordinary species that changed our world
Quiet Endurance, Longevity and Strength
Monolithic is the word that first comes to mind. The second is cavernous, the third, hydra. A broken ring of grasping tentacles sprouts above a woody cave, its exterior bossed with warts and knots, twisted in places as if it had been given a Chinese burn by a giant hand. In places, yawning gashes in the saurian skin have opened up allowing rainwater to create rock pools several feet above the ground. This vast squat entity is so old that it was probably well grown when the Domesday Book was compiled in 1089 – a veteran English oak.
English oaks are famously long-lived. An old saying goes that an oak takes 300 years to become adult, 300 to mature and another 300 years to die. The tree described above is the Old Man of Calke, which takes pride of place among a host of ancient trees at the National Trust’s Calke Abbey, growing in parkland where their branches are able to spread, free of close competition. Mature oaks look their best when given space.
At Moccas Park in Herefordshire there is an extraordinary collection of trees in an ancient park that was formerly wood pasture, mature woodland undergrazed by livestock. Its oaks were immortalised by the Reverend Francis Kilvert, vicar of the nearby church at Bredwardine who wrote in April 1876 of a visit to Moccas:
As we came down the lower slopes of the wooded hillside … we came upon … what seemed at first in the dusk to be a great ruined grey tower, but which proved to be the vast ruin of the king oak of Moccas Park, hollow and broken, but still alive and vigorous in parts and actually pushing out new shoots and branches … I fear those grey old men of Moccas, those grey, gnarled, low-browed, knock-kneed, bowed, bent, huge, strange, long-armed, deformed, hunch-backed, misshapen oak men that stand waiting and watching century after century … No human hand set those oaks. They are ‘the trees which the Lord hath planted’. They look as if they had been at the beginning and making of the world, and they will probably see its end.
This apparent immortality and ability to transform as it ages make the English oak magnetic, both for us and for wildlife. Oak supports hundreds of invertebrates, more than any other British tree, and as it grows in girth, fungus creates weaknesses, crannies and fissures appear in its trunk, providing a home for owls, bats and many other animals. There are two native species of oak, both with distinctive roundly lobed leaves. The English or pedunculate oak has stalked acorns and very short leaf-stalks and tends to be commoner in the lowlands; sessile oak has unstalked acorns which sit on the twigs and longer leaf-stalks and is more frequent in the north-western and western parts of the British Isles. To make life more interesting, the two species hybridise freely and in many places the hybrid can be the most common oak. Providing shelter for our wildlife and, as we’ll see, for our navy and even for a king, the oak is a remarkable tree.
But it can be easy to overlook. Visitors to the Natural History Museum’s Treasures Gallery could be forgiven for keeping their eyes focused on the collection of twenty-two exhibits gathered together, chosen to showcase the range and variety of the museum’s collection. These include: the skeleton of a dodo; one of three precious emperor penguin eggs collected by the polar explorer Apsley Cherry-Garrard; a Barbary lion skull unearthed from the royal menagerie at the Tower of London; and a piece of moon rock brought back to earth by the Apollo astronauts. But glancing upwards, they will come face to face with an extraordinary work of art.
Tree, by Devon-based artist Tania Kovats, is a 17-metre longitudinal section of an entire, 200-year-old oak tree. The branches, trunks and roots have been cut into wafer-thin pieces and inlaid into the gallery’s ceiling. Against the white background, the pale buffish-yellow of the tree’s interior, its grain etched across the surface as if delicately drawn, stands out. Looking up, the effect is to place you, the viewer, at the very heart of a huge oak tree.
She was inspired by leafing through one of Darwin’s early notebooks:
The words ‘I think’ are written at the top of the page, and the spindly lines become a branching form resembling a tree. Seeing the original is like standing over Darwin’s shoulder as the thought emerges. To me it actually looks like thought, given how significant the tree form is in representing our thought processes. The tree is a model of connectivity, ancestry and genealogy, and each branch traces change or chance.
When it came to choosing a particular species of tree to represent Darwin’s thoughts and ideas, there was only one contender:
I wanted to express scale, to create something big, and an oak is like the blue whale in the woods … I wanted something old, something that has been here a long time. We think in tree shapes. The idea of ancestry, for example, is expressed in trees, the family tree. Trees are an image of connectivity, thoughts branching out but connected to where they came from.
We have rested beneath the shade of oaks in summer, sheltered beneath them from rain in winter, climbed them as children, collected their acorns, and over centuries used their bark and wood for everything from building great vessels such as the Tudor flagship the Mary Rose, Captain Cook’s Endeavour and Nelson’s Victory, to buildings, including the ceiling of the House of Commons.
The oak tree is at the heart of both ancient and modern cultures across Europe, Asia and North America. It was sacred to the Greeks, where it was closely associated with the god Zeus; to the Romans, whose emperors were often presented with crowns made of oak leaves; and to the Druids, who would worship in oak clearings. Druids worshipped the spirit of the oak and the parasitical mistletoe that grew on it. Roman history and natural history is full of speculation about the Druids’ dark secrets. Here is Tacitus’s vivid description from the Annals of the decisive battle between Suetonius’s army and the British Druids in AD 60:
On the opposite shore stood the Britons, prepared for action. Women were seen running through the ranks in wild disorder; their apparel funereal; their hair loose to the wind, in their hands flaming torches, and their whole appearance resembling the frantic rage of the Furies. The Druids were ranged in order, with hands uplifted, invoking the gods, and pouring forth horrible imprecations. The novelty of the fight struck the Romans with awe and terror. They stood in stupid amazement, as if their limbs were benumbed, riveted to one spot, a mark for the enemy. The exhortations of the general diffused new vigour through the ranks, and the men felt the disgrace of yielding to a troop of women, and a band of fanatic priests; they advanced their standards, and rushed on to the attack with impetuous fury. And the Britons perished in the flames, which they themselves had kindled … The religious groves, dedicated to superstition and barbarous rites, were levelled to the ground. In those recesses, the natives had stained their altars with the blood of their prisoners, and in the entrails of men explored the will of the gods.
The thoroughness of the Roman destruction of the sacred groves and suppression of the Druids meant there are many gaps in our knowledge of ancient religious beliefs and practice but recent archaeological breakthroughs, particularly in the area of dendrology (the science and study of wooded plants) have shifted the way we see the ancient world’s relationship with nature.
The most telling evidence of the oak’s ancient importance was discovered in 1998 in the beach at Holme-next-the-Sea, Norfolk. Four-thousand-year-old Seahenge was constructed of a circle of oak timbers with a huge, upturned oak boss at its centre. It was the oaken altar used in Bronze Age funeral rites. At low tide, Seahenge’s snaggle-toothed circle of stumps loomed out of the mud, casting ancient shadows across the ooze. Dr Francis Pryor, archaeologist and author of Seahenge, believes the symbolism of this upside-down oak is key to understanding the Bronze Age mind.
We often find everyday objects deliberately turned upside down at Bronze Age sites. The inverted oak is a very complex statement. It is the world turned upside down, just as death is an inversion of life. From a ritual point of view it symbolises taking objects out of this world and placing them in the next.
We have focused on the stone circles and monuments left starring our countryside because they’re the ones that remain but Seahenge shows there were probably many more less permanent wooden ones crucial to Bronze Age beliefs. Oaks also appear throughout myths and legends, in the Bible and fairy tales. The Norse god Thor – god of thunder – is also associated with oaks, possibly because the oak is more likely to be struck by lightning than other trees, growing as it does so commonly and often in the open. In their Compendium of Symbolic and Ritual Plants in Europe, Marcel de Cleene and Marie Claire Lejeune compare the status of the oak with that of two other unchallenged natural symbols: ‘Thus, the biggest, strongest and most useful tree became the king of the plant kingdom in Europe, just as the lion is the king of land animals and the eagle rules the skies.’
Oak has remained an important symbol throughout our more recent history too. Royal Oak Day was for two centuries an official public holiday, marked out with bonfires, peals of bells and special church services. When Charles II rode into London on his birthday, 29 May, in 1660 and restored the monarchy to Britain, the day was officially declared one of national celebration. Royal Oak Day celebrated the new king’s chosen trademark. After losing the Battle of Worcester in 1651, and on the run from Cromwell’s forces, Charles had hidden in an oak tree as his enemies searched the surrounding Shropshire woodland. Charles later told Samuel Pepys that while he was hiding in the tree, a Parliamentarian soldier had passed directly below it. The exhausted prince had fallen asleep, and his worried companion was ‘constrained … to pinch His Majesty to the end he might awaken him to prevent his present danger’. A vivid symbol of his lowest moment, the choice of the oak leaf showed an appealing sense of the humility his father had lacked. This story is still commemorated on the signs of more than 500 pubs across the country, making ‘The Royal Oak’ the third commonest pub name in Britain even today. (Incidentally the tree standing on the site today is not the original but a 200- or 300-year-old descendant known as ‘Son of Royal Oak’. The original Royal Oak was destroyed during the seventeenth and eighteenth centuries by over-enthusiastic tourists who cut off branches and chunks as souvenirs.) Chelsea Pensioners still wear oak leaves in memory of Charles’s escape from capture.
Royal Oak Day managed to combine the celebration of recent history with many of the most popular features of pagan spring celebrations, including maypoles. The dominant custom of the day was the wearing of sprays of oak leaves (preferably with an oak apple attached), which were worn by ‘almost everybody, high or low, male or female, adult or child, throughout the eighteenth and nineteenth centuries’. Representing a return to the spirit of ‘merry England’ so harshly suppressed by the Puritan revolution that they had even banned Christmas, it was wildly popular. A spirit of misrule reigned. Any child who did not wear their oak leaves was ‘attacked unmercifully by their school-fellows and could be pinched, stung with nettles, kicked or pelted with birds eggs (sometimes rotten ones)’, according to folklore historian Steve Roud in The English Year. The day was officially Royal Oak Day but all the local terms for it rapidly dropped the historical element in favour of the natural and it was known as Shick-Shack (dialect for oak apple), Arbour Tree or Oak and Nettle Day.
The Green Man, a motif showing a human face made of leaves (often those of the oak), is found in many ancient cultures, and appears to be a pagan spirit related to fertility and rebirth. Another man in green, the legendary outlaw Robin Hood, is said to have made his hideout in an ancient oak tree known as the Major Oak, in the heart of Sherwood Forest. All over England places have been immortalised by their famous trees: Bowthorpe Oak in Lincolnshire, is thought to be 1,000 years old, while Marton Oak in Cheshire is even older; and the Crouch Oak on the borders of Windsor Great Park in Addlestone, Surrey, is said to be the tree under whose shade Queen Elizabeth I, on one of her lengthy summer progresses around the kingdom, stopped for a picnic.
Britain is also full of place names that refer to oaks, from Accrington (acorn farm) to Sevenoaks (which should perhaps have been renamed when six of its seven original ancient oaks were destroyed in the Great Storm of 1989). The north London district of Gospel Oak – marking the parish boundary between Hampstead and St Pancras – is a survivor of an ancient tradition of gospel oaks, once widespread through the country, that were once taken as convenient, enduring marks of the exact boundary line. Before the Reformation, crosses were carried and traced on the ground, and the gospels were said or sung to the corn under the Gospel Oak. Geoffrey Grigson suggests that that could have been ‘some survival of tree worship in this respect for the oak tree’. After the Reformation the ceremonies weakened, and were gradually abandoned.
Behind all these symbolic, cultural and practical examples, there is a real, living tree. So what exactly is an oak, and why does it hold such an important place in our lives, and in the lives of so many other plants and animals?
Just as there is no simple, self-contained definition of a ‘tree’ – either in botany or popular culture – so there is no easy way to define an ‘oak’. This is partly because there are so many different kinds – at least 600 extant species – but also because people around the world have named various trees ‘oaks’, even though they belong to other tree families. Most oaks, however, belong to the genus Quercus, and are native to the northern hemisphere continents of North America, Europe and Asia, with the greatest variety of species occurring in the United States and Mexico, and also in China. Oaks can be either deciduous – losing their leaves in autumn in order to conserve water – or evergreen, keeping their leaves all year round.
But when we speak of ‘oaks’, we usually mean the English oak Quercus robur. Also known, because its leaves grow on a long stem, or peduncle, as the pedunculate oak, this is the commonest tree species in Britain, with its main strongholds in the southern and western parts of the country, on wet, clay soils. Some ancient specimens have reached a height of 40 metres, though most are closer to 20 metres. Strangely, the tallest trees are not, as you might expect, the oldest: oaks stop growing after about 300 years, and may even shrink as they get older to prolong their life. They also grow hollow as they age.
English oaks are easily identified by their distinctive leaves, arranged spirally around the twig, with four or five individual ‘fingers’ or lobes on each side, creating the classic shape with which we are so familiar, and which are produced in bunches from May onwards. In spring oaks also produce both male and female flowers – the male flowers being long and easily visible catkins, while the female flowers are much smaller. Pollen from the male catkins is blown by the wind to fertilise the female flowers.
Over the summer these gradually mature into fruit known colloquially as an acorn. The name comes from the Old English word aecern, and not, as is sometimes suggested, a corruption of ‘oak’ and ‘corn’. In fact the word simply means ‘fruit’ or ‘nut’, and although this originally applied to any species, during the medieval period it gradually attached itself to the particular fruit of the oak tree, which was an important foodstuff for swine. Green at first, as they ripen acorns turn a pleasing shade of brown, and when mature they loosen in their cups and eventually fall from the tree. The vast majority of these will never germinate, as they are swiftly collected and eaten by a wide range of woodland creatures including deer, mice, red and grey squirrels and jays. But not all the acorns they collect are eaten straight away; in autumn, both jays and squirrels regularly store them as an insurance against food shortages later in the year. Unable to remember where they bury every one, they inadvertently help spread the seeds; indeed oak woods have spread to higher altitudes through jays carrying the acorns uphill.
Oak apples, by the way, only look like fruit: they are galls created by a small wasp which induces by chemical means abnormal growths in the oak tissues to create a safe home for their grubs. Oak apples are just one of many species of oak galls that can grow on the leaves, the catkins, the acorns, the twigs or the bark.
As an oak tree matures, it forms a characteristic shape, with a broad, spreading crown and thicker, sturdier branches beneath, at right angles to the main trunk. Because unlike beech trees their canopy is relatively open, it allows plenty of sunlight through to the forest floor, which gives oak woods their varied flora, notably primroses and bluebells.
Oak trees – and oak woods – provide excellent habitats for wildlife, supporting a far greater variety of species than any other native tree. Almost 300 different kinds of insects, from moths to beetles and weevils to wasps, depend on oaks, as do many species of birds and mammals. These include hole-nesting birds such as tits, woodpeckers and nuthatches, and treecreepers, which nest in crevices beneath the bark.
Three long-distance migrants from Africa, the wood warbler, redstart and pied flycatcher, arrive back in our western sessile oak woods each spring to breed; while other wildlife supported by oaks includes bats, which roost beneath the bark or in old woodpecker holes, several hundred species of lichen, and a wealth of fungi, which thrive in the leaf mould created as the fallen leaves decay in autumn. So many caterpillars feast on oak leaves it is amazing that the trees survive. Species whose common name contains the word ‘oak’ include the oak bush-cricket, oak jewel beetle, oak woodwasp, oak mining bee, oak leaf-roller weevil, and a whole range of moths, such as the oak eggar, oak lutestring, oak hook-tip and the evocatively named oak beauty.
However, not all moths enjoy such a benevolent relationship with this mighty tree. In recent years, naturalists and conservationists have become increasingly alarmed by a non-native moth, the oak processionary, which first appeared in Britain from its home in southern Europe in 2005. Its caterpillars seriously damage the tree’s foliage, eventually even leading to its death. And it’s not just the oaks that are under threat. It’s us too: the caterpillars’ toxic hairs present a real danger to the health of nearby humans.
The oak tree – and its leaves – has often been used as a kind of symbolic shorthand because of its perceived values of endurance and longevity. Oaks feature on the coat of arms of Estonia, as the logo of Britain’s Conservative Party, and on coins in both Germany and the UK. Oak leaves are also the symbol of both the Woodland Trust and the National Trust. And the oak is Britain’s national tree, though fifteen other countries or provinces, including Estonia, Germany and the United States, also claim it as their own; as too, unfortunately, did the Nazi regime, in which the Knight’s Cross with Oak Leaves was the highest honour a soldier could win.
The tree’s products, including its bark, acorns and galls, were widely used in herbalism and ancient medicine, as a cure for a range of ailments from snake bites and mouth sores to diarrhoea and kidney stones; while until the cultivation of wheat began, about 10,000 years ago, acorns were ground up for flour. Today, we still use oak to make barrels in which the finest wines and malt whiskies are left to mature for years or even decades, the oak imparting its subtle flavour to the liquid within.
One of the main reasons the oak is so dear to our hearts is not, however, symbolic, but practical. The linguistic root for oak is ‘dur’ and among its meanings are ‘door’ and ‘durable’ (it has been suggested that the word Druid also derives from it). Our place names remember it: Derwent, Darent and Dart all mean ‘river abounding in oak’. Oak timber is one of the densest, hardest and most durable of all woods – indeed the second part of the English oak’s scientific name, robur, derives from the Latin meaning ‘strength and power’. Oak timbers have been used for centuries to make beams for houses and also ships; hence the naval association. The timber is just as long-lasting as the tree itself; perhaps even longer: the tomb of Edward the Confessor in Westminster Abbey is as strong today as when it was carved, almost 1,000 years ago.
Peter Ackroyd wrote: ‘Oaks mean something to us and somehow the old oak stands for England.’ And the sense that the oak is at the heart of what it means to be both English and British (whatever exactly that means) has found an outlet again and again in patriotic song and poetry. We’ll leave you with ‘Heart of Oak’ – originally composed more than 250 years ago – which is the official march of the Royal Navy. Its words, by the eighteenth-century actor and playwright David Garrick, were written as a rallying cry to sailors:
Heart of oak are our ships.
Heart of oak are our men;
We always are ready;
Steady, boys, steady;
We’ll fight and we’ll conquer again and again.
In a purely technical sense, each species of higher organism – beetle, moss, and so forth – is richer in information than a Caravaggio painting, Mozart symphony, or any other great work of art.
Edward O. Wilson