How Scotland lost the ‘great wood’ of Caledon

Northern Britain was once covered by a huge forest of native pines, sheltering teeming flora and fearsome fauna – or so the story goes. Here’s the twisted tale of its rise, fall... and the remarkable tree that built it.

A view of Rothiemurchus Forest in the Cairngorms National Park – one of the largest fragments of native pinewood forest remaining in the country.

Photograph by Nature Picture Library / Alamy
By Simon Ingram
Published 22 Apr 2022, 09:57 BST

LOOK RIGHT as you head north from Kinlochewe in Scotland’s north-west Highlands and soon you will soon see the sleek, mountain-fringed waters of Loch Maree. Some 65 uninhabited islands  scatter the loch, itself the fourth biggest in a land of tens of thousands.

Upon the islands lie graveyards sited adrift to evade scavenging wolves, holy wells, ruined hermitages. And stands of slender-trunked, broccoli-canopied trees that decorate a scene that would be somehow naked without them. At dawn they reflect in the stilled waters of the loch, a sight beloved of those seeking the aura of this instantly charismatic landscape. To modern eyes misted by romanticism, a scene like this says ‘Scotland.’

(Related: see amazing images of Scotland's great wilderness.)

The Loch Maree islands are a fine and famous monument to what recently became the Scottish national tree. England may have the stately oak, but beyond the border, the northern land indisputably belongs to the Scots pine.

Or rather, it did. For while stands of the striking red-barked tree are still ubiquitous across Scotland, they are a fragment of what was. Legend tells of an ancient wildwood that covered much of the country, scaring off invaders and sheltering predators – lynx, wolf, bear – now long gone from our lands. Those who know the story of the wood call it by the name the Romans gave Scotland: the Great Wood of Caledon. And while its history is murky, the wood itself may have been anything but.

Scots, but not just Scottish

Though intrinsically associated with the story of the ‘lost’ great wood, as a species the Scots pine is remarkably adaptable and opportunistic. Pinus silvestris var. scotica is the specific name for the Scottish tree’s genetic lineage, but despite its geographically suggestive name, the Scots pine pops up in plenty of other places.

“From an ecological perspective it’s a pretty spectacular species,” says Tom Ovenden, a forest ecologist and PhD researcher at the University of Stirling. “It has a crazily accomplished distribution.” He indicates a map that paints a green rash, denoting Scots pine distribution, across much of the northern hemisphere – from a dot in Scotland, to total coverage of Scandinavia, Eastern Europe and central Russia, almost to the Pacific coast. “It is one of the most widely distributed conifers in the world. The ecological and environmental envelope that is encompassed within that range is huge.”

The Prima Europe Tabula, or first map of Europe from 1480, was extracted from Greek scholar Claudius Ptolemy's Geographia, produced in the second century AD. On it, as a green blob, is the 'Caledonia Silva' - the Scottish forest. This menacing wood, greatly embellished, was possibly used as an excuse by Romans for their inability to conquer the wild northern lands of Scotland. 

Photograph by National Library of Wales

Ovenden describes the tree as an early successional species – “like birch, one of the [trees] that crops up first in a freshly cleared area” – due to light seeds that disperse easily. “They are adapted to grow up fast in relatively high light conditions, and does well in freely-draining, quite sandy soils. Which is why there are so many still in the Cairngorms.”

It’s also hardy, and may be able to handle an ever-warming climate better than other trees. “Scots pine is considered to be a relatively drought-resistant species,” adds Ovenden. “Older tree bark is thick and fire-adapted, so short, hot intense fires could sweep through the understorey, and the bark insulates the live part of the tree.”

(Related: forests are reeling from climate change - but there is hope.)

However widely scattered the Scots pine, nowadays Scotland’s principal timber tree is the Sitka spruce. Native to the similarly damp climate of the American northwest coast, this exceptionally well-adapted tree was introduced en masse to grow a national timber reserve after World War Two, and now thrives – its densely-packed, shadowy-floored regiments starkly at odds with its more flamboyant native counterpart.  

Reflected in the waters of Loch Maree, a stand of Scots pines. On neighbouring islands lie some of the oldest and most undisturbed of Scotland's ancient forest sites. But were they once part of a much greater whole? 

Photograph by Jim Richardson, National Geographic Image Collection

Mighty pines from seedlings grow

But however evocative and ancient its associations, the Scots pine is not a time machine tree as an individual. Thousand year-old oaks can be found in England; many sequoias of California’s Giant Forest date from before the time of Christ. A yew still stands in the Scottish village of Fortingall that may be a living link with the Bronze Age. The possible oldest tree of all is a pine – California’s Great Basin Bristlecone, which at 4,800 years old was sprouting around the time Stonehenge was built. But Scots pine trees have no such longevity, with a typical lifespan of around 250 years and a long one of around 500. What endures, however, is the environment cultivated by its presence.     

“Because Scots pine has been here a long time, a lot of other species exist within the habitat it creates,” says Tom Ovenden. “Wood ants, stuff like that. And the structure of those remnant fragments is different from any plantation forest. Caledonian pinewoods have lots of deadwood, lots of fallen trees, and that provides habitat for particular invertebrate species or fungi species that come along later on in the development of a forest. You get a much greater species diversity pool compared to, say, a 10 year-old pine plantation forest – to use an extreme example.”

(A photographer explores Europe's ancient old-growth forests.)

Palaeoecology and studies of remnants can tell scientists so much, but the extent of the ancient wood of Scotland has to largely be guessed at – but when clues are found, they can be dramatic. “The best evidence is the remains of tree trunks or roots preserved in peat,” says Dr Richard Tipping, a former University of Stirling professor whose research work focussed on Scotland’s environmental archaeology and the changes in vegetation over the ages. “Pine trees grew at times on dry peat surfaces, where they had a competitive advantage over other tree species. As growing peat reduces oxygen and so decay, the bleached ‘bones’ are tangible evidence for where trees once were.”

An old Scots pine reveals a resplendent branch structure in a mixed native wood in Glen Strathfarrar, Highlands. While Scots pine is often associated with the tales of Caledon, many native species made up the once much more extensive tree cover of the Highlands.

Photograph by Nature Picture Library / Alamy

While the modern living patches of ancient forest stand in plain sight, they are few. These remnants – 38 substantial fragments in all, and 84 if individual stands are included – are classified generally as ‘Caledonian pinewoods.’ The term isn't wholly accurate, however, as while some areas of the old forests are dominated by pine, others are dominated by old-growth birch, and oak along much of the Atlantic coast. Other species, past and present, include willow, aspen, juniper, alder, rowan, ash and hazel.

The pine-dominated woods, what most people think of when picturing the legendary Great Wood, are found most impressively in locations such as Rothiemurchus in the Cairngorms, Abernethy and Glen Feshie, and also in a scattergun spread down the west coast and the central belt in places such as Glen Avon, Glen Orchy, the Black Wood of Rannoch, Glen Affric, Loch Arkaig – and those islands in Loch Maree. All are locations that have been much romanticised for their conjuring of Scotland’s ‘past’ forest landscape, as opposed to its ‘present’ forest landscape – which essentially means wild, versus human-crafted.

A Scots pine root fragment emerges from peat in the Northern Highlands of Scotland. Whilst the pine prefers quick-draining soil, its tenacity allowed it to grow where other trees wouldn't – and remnants of ancient forest often turn up as 'bones' preserved in the peat. Such remnants can help ecological archaeologists establish where forest once stood.

Photograph by David Robertson / Alamy

But while the idea of an ancient, contiguous wildwood is a tempting legend, the true story of Scotland’s great forest could be somewhat less binary – are rather more scurrilous – than simply a case of humans versus nature. Though in a strange way, that may have been how it started.  

The ‘great wood’ – history or myth?

“I don’t think of the Great Wood of Caledon as a thing of nature at all. I think it was built by the Romans. Or at least, its reputation was.” So says Jim Crumley, a Scottish natural history writer whose book The Great Wood took the legend of Caledon to task. According to Crumley, the wood was exaggerated by the Romans as a way of explaining to superiors why – upon reaching the northern frontier of their Empire in the Southern Scotland of today – they failed to proceed any further into a land of rough terrain, a furtive climate and wild tribes that defied suppression. What these nervous would-be conquistadors needed was an excuse even generals back home would accept.

“Word-of-mouth testimony was taken back to Rome by soldiers who found, in Highland Scotland, a realm beyond their comfort zone… but would rather not admit it,” Crumley writes in an email to National Geographic (UK). These whispers “cloaked their retreat in stories of an impenetrable forest. Tacitus wrote it down, and Ptolemy wrote the words ‘Caledonia Silva’ [Scottish forest] on a map.”

For all the rumoured Roman reports of an impassable forest, it's likely by the time any Romans saw it, any wood they found was already a shadow of its former extent.

The pinewoods had gradually established themselves in the bare landscapes of Scotland following the last glacial retreat, around 13,000 years ago – a time when little more than moss covered the tundra-like environment. The tree cover was likely to have been at its maximum at around 6,000 years ago – and already considerably chipped away at by various agents by the time the Romans clapped eyes on it some 3,000 years after that.

According to Crumley, the Romans’ placing of the forest on their rudimentary maps were repeated on maps from the 1500s onward – and its position and size changed as the maps were refined. As a result, “when you walk the landscape of 21st century Scotland, your views are clouded by legend,” he says. But there are other reasons to doubt the perception of the wood as an impassable thicket – it may have had to have been spread out just to survive.

“The old idea of a dark, dank, dense and forbidding wildwood has faded, principally because many trees do not set seed in their own shade,” says Richard Tipping. ”For regeneration, there must be open spaces. These open spaces would have been created by disturbance at different spatial scales, like tree-throw in storms, lightning-strike fires, flooding or natural death of individual trees.” He adds that “the comparatively new idea that there was much open ground [in the ancient forest] has not been supported by evidence.”

The canopy of Scots pine in Abernethy Forest, Perth and Kinross. Abernethy is the largest fragment of old-growth pine forest in Scotland.

Photograph by Jan Holm / Alamy

That’s not to say there wasn’t ever an extensive wood, with all the natural bounty that implies. According to Jim Crumley, there were probably four.

One, he states, may have occupied the Trossachs region, “from the upper reaches of the [River] Forth in the south to the upper reaches of the Tay in the north.” Another extended amidst the West Highlands “from Glen Strathfarrar in the north and the other parallel glens west of the Great Glen, and as far south as Mull”. Of the remaining two, Crumley notes a stretch in the Cairngorms National Park, “where a scrap of the original treeline is still to be found 2,200ft up at Craig Fiaclach. There you wade among knee-high trees that grow sideways and your mind turns summersaults at how much is lost.”

The last location, he says, perhaps formed the most extensive and dramatic tract of ancient forest – the “greatest of the great woods” – located in the muscular landscape of the Central Highlands between Loch Tay, Rannoch Moor, Loch Awe and Glen Dochart in a tapestry of woodland comparable in size to Greater London. Of the area, which today is made of striking spaciousness amidst mountain, moor and forest, Crumley says, “its potential for 21st century conservation is immense. It’s where we should reintroduce the wolf.”

(Read: Lynx and wolf may soon be roaming Britain’s wild places again. Is it a good idea?)

The capercaillie – a member of the grouse family – was reintroduced to Scotland in 1837, immediately making its home in the native pinewoods. 

Photograph by Mark Medcalf / Alamy

The Scottish wildcat's habitat mirrored that of the remote pinewoods. Gradually, its range deteriorated, and intermingling with domestic cats has made the species – after the local extinction of the lynx, the only wild felid in Britain – genetically compromised except in a few locations.

Photograph by Nature Picture Library / Alamy

Withering of the wood

So where did the ancient forest go? Much like its spontaneous creation, was the downfall of the great wood simply part of the ebb and flow of the landscape’s natural cycle over the centuries? “’Ebb and flow’ imply fluctuations around an equilibrium, with no long-term shift,” counters Richard Tipping, though he adds that “natural climate change will have affected trees growing at the ends of their ranges, causing shrinkage or fragmentation of forests.”

But whichever way it’s cut, there’s dramatically less native forest than there was – an estimated 1,500,000 hectares of pine habitat alone, down to around 17,900 hectares today. As a result, there is less cover for predators, less biodiversity, and less natural order than nature might have specified – were it not for one aggravating factor. “Human beings will have created most of the decline. Farming communities need open ground,” says Tipping.

This gradual deforestation of the wood likely began in the Bronze Age, around 4,000 years ago, with land opened first for hunting, then grazing. This developed through the Iron Age, then the Middle Ages – with the demand for wood as a material for ships and buildings, open land for settlements and fuel for forges steadily grew.

As the centuries progressed, hunting claimed the last of the apex predators whose stronghold was the forest. Then, beginning in the late 18th Century, the Highland Clearances saw huge swathes of land monopolised for sheep farming, with low-impact crofters turfed out and livestock shipped in – the latter nibbling away any chances of seedling regeneration and rapidly wiping out younger-growth trees, leaving only what ecologists term the ‘granny pines’. Shooting estates were established which had either little need or an active disdain for forest shelter.

“A scrap of the original treeline is still to be found 2,200ft up at Craig Fiaclach. There you wade among knee-high trees that grow sideways, and your mind turns summersaults at how much is lost.”

Jim Crumley

Elsewhere, the Industrial Revolution saw an acceleration in felling. Timbers were harvested for shipbuilding in Glasgow and Edinburgh, and even lined the Allied trenches of the First World War. The even more ecologically costly Second World War galvanised Britain’s desire for a self-sufficient source of timber, and so the Sitka spruce was introduced from North America. Its rapid growth and ease of intensive planting leading to widespread clearing, ploughing and disruption of old forest, and out-competition of native species – reaching a zenith in the 1960s and 1970s. (Read: Scotland has a rainforest – and it’s in trouble.)

Many of the native species that mostly relied on the woods – red squirrel, capercaillie, pine marten – are now restricted or the subject of conservation programs. Others, such as the Scottish wildcat, hang by a thread. Some, such as the boar and the beaver, the brown bear, Eurasian lynx and wolf, were wiped off the native map long ago, along with most of their habitat. Plants like the luminous, delicate twinflower, (Linnea borealis) a relic of the ice age, were severely depleted with the native forests, and now only exist in a handful of the pinewood fragments.

A resonant character

While substantial tracts do remain – the largest at Abernethy and Glen Affric, and the most undisturbed in Torridon and those Loch Maree islands – most old-growth remnants today occupy high, remote or inaccessible sites that lie outside the realm of human utility. Conservation projects emerged in the 1990s to help restore and extend the woods. Control of deer distribution, and a less invasive approach to timber growth (Sitka spruce and also Scots pine are still planted as a timber tree) are all playing a part, though with no illusion of recapturing a landscape from a different time, in any sense. Even if that were possible, the land itself has moved on.

“Although Scots pine is native to Scotland and has been here a long time, in the conditions under which it was previously very dominant… there weren’t species like Sitka spruce here then,” says Tom Ovenden. Given a withdrawal of human influence – a complete rewilding, if you like – “how would Scots pine compete? If I was to speculate, you would end up with a mosaic of species and different developmental stages across the landscape, partly dictated by whatever climate we end up with in the next couple of hundred years, and by what other species are there. I can’t imagine you’d just end up with blanket Scots pine.”

Ovenden adds: “The continual change of ecosystems over time is a bit like evolution – it doesn’t go backwards. It can only change into something new, even if that might resemble a previous state.”

Scots pine cluster around the edges of Scotland's Loch Maree, with the mountain of Slioch in the background. 

National Geographic photographer Jim Richardson, for whom Scotland is a favoured location, appreciates the aesthetic of the Scots pine as well as its spirit, both of which are conversant with the landscape they inhabit. “The Scots pine forests have a character very resonant with Scottish character, at least in my book,” he says. “Gathering in small groups on knolls in the valley or up on the hills skirting the heather. Stolid and stubborn, a bit more rugged and less prettified than lesser forests that live in easy, comfortable climates. And delights to explore, given that the trees are so individualistic.”

As for the all-consuming Great Wood of Caledon, if it inspires wonder and appreciation, does it matter if its specific nature was something of a myth? “It troubles me because what we know of nature’s truth is infinitely more fascinating,” says Jim Crumley. “But I do know this: a deeper understanding of that truth will help us to undertake the only worthwhile task in the landscape of the four great woods. Which is to heal it.”

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