We all know that deforestation is a global problem. But it isn’t so obvious that humans have been clearing Scottish woodlands for millennia. Only a tiny fraction of our original native forest cover remains. The history of deforestation in the Highlands is long and complex, but we can still gain glimpses of what we have lost.

 

The ice retreats

Imagine time-travelling to the Highlands around 11,500 years ago. The glaciers of the last ice age were in retreat. As the climate warmed, colossal rivers of ice had given way to open, treeless tundra, and then to scrubby woodland. From our time machine we can see hardy shrubs like dwarf birch, willows and juniper getting a foothold. Hazel, aspen, birch, pine and other trees are also slowly making a comeback.

All the while, plants, fungi, mammals, birds and many other organisms are returning. They are reclaiming land gripped by ice for thousands of years. Britain is still attached to the rest of Europe. So much water is still locked up in ice, the English Channel and the North Sea don’t even exist . . .

 

Scotland’s ancient forest

Woodland expanded and reached a peak around 6,000 years ago. Wildlife flourished in a mosaic of trees, heath, grassland, scrub and bog. Lynx prowled the denser woodlands and packs of wolves hunted deer. Giant wild cattle (known as aurochs) grazed savannah grassland, while boar rooted through the leaf litter. Bears scooped salmon from the rivers, and elk grazed in the willow meadows created by the dams of beavers. Many different birds were abundant.

Woodland shifted and moved with no fixed boundaries. Among the many tree species were Scots pine, aspen, birch, oak, rowan, holly, willow and alder.

 

The arrival of farming

Early farmers arrived on the scene about 5,900 years ago. (Humans had been around much earlier, but we don’t know what impact they had.) These Neolithic farmers grazed cattle, goats and primitive sheep. They burned areas of heath and pinewoods to encourage fresh growth of heather for their stock. Burning plus grazing was bad news for trees. Woodland couldn’t recolonise denuded areas and went into further retreat.

 

Climatic changes

Climate shifts and changes over time and forests change with it. Around 3,000 years ago, a period of cold, wet weather began. The conditions were ideal for peat bogs to spread. In some areas, especially the north and west, this was not so good for tree growth. The tree line became lower, and in the wettest areas scattered broadleaves replaced pine.

Even so, there was still a vast network of woodland at this point, mixed with heath, bog and scrub. It seems likely that trees would have regained a lot of old ground as the cold, wet period ended. But the plot thickens …

 

The decline continues

Through the centuries that followed, people cut down trees for timber, fuel and to make way for agriculture. Livestock grazing continued to limit tree regeneration. The forest was forced into smaller, isolated pockets.

Roman accounts speak of a vast ‘Caledonian Forest’, but their accounts are exaggerated. By the time the Romans arrived, over half of our native forests had been lost. It was not a dense blanket of pine woodland (as was once thought), although native pinewoods were a key part of this forest.

We now use the term Caledonian Forest to evoke the, wilderness that spread across 1.5 million hectares of the Highlands in prehistoric times.

In the Medieval times Norse and Celtic people felled trees for ships, houses and more. The Little Ice Age in the 14th Century sped up the decline. From the 17th Century the demands of wars and industry, and a growing Highland population all took their toll. But the worst was still to come.

 

An all time low

By the 18th century, woodland cover reached its all time low. Some pinewood fragments were protected from overgrazing because timber had value, but cheap timber imports later changed all that.

The Highland Clearances were a devastating blow for Highland people and culture. They also made way for large scale sheep farming, which was an ecological disaster.

In Victorian times sheep farming declined and landlords turned to sport shooting for income. Deer stalking encouraged unnaturally high numbers of deer and grouse moors were burned. Regenerating trees stood little chance.

 

The rise of forestry

Both of the World Wars took a heavy toll on the trees we had left. Wood was essential for the war effort and in the First World War Britain almost run out of timber. The government created the Forestry Commission in 1919 to prevent the same situation happening again.

Fast-growing introduced species such as Sitka spruce were used to create dense plantations. These support a limited range of wildlife compared to ancient, native forests. Native trees were both felled and underplanted. Many native woodlands were damaged or lost.

(Priorities have since changed. The Forestry Commission (now Forestry and Land Scotland) has carried out a lot of excellent work to help reverse the situation.)

 

The ecological effects of deforestation

Such large-scale, long-term ecological destruction has transformed the Scottish Highlands. Today only around 1% of our native pinewoods remain, while many other habitats have been degraded or lost. The besieged remnants are in a state of poor health for many reasons. Let’s look at a few of them below.

 

Fragmentation

One patch of pinewood may be many miles from its nearest neighbour. The species within a fragmented woodland are more vulnerable to inbreeding and natural disturbance. Storms, disease and fire are important part of a large dynamic forest, but habitat that’s been broken up may not recover from such events.

 

Loss of wildlife

Key wildlife species have been lost due both habitat destruction and hunting. This has had a catastrophic effect. When species are removed, the ecological tapestry begins to unravel.

The top predators – wolf, bear and lynx – were all hunted to extinction by humans. Beaver, aurochs, elk, wild boar and others suffered the same fate. These animals each have an important, unique role in a forest, keeping it rich and diverse.

Predators keep herbivore numbers in check. They also keep nibbling mouths on the move, allowing vegetation to regenerate. A lack of predators is a major reason why deer numbers are now so damagingly high.

Herbivores’ feeding habits in turn create a varied structure in the forest, along with other important effects. Many other less obvious creatures have also been lost or have had their numbers decimated.

 

Soil

Deforestation changes the structure and fertility of the soil. Woodlands are better at holding onto nutrients than overgrazed grassland are. Because of this the loss of woodland cover can result in the soil becoming impoverished. And less hospitable to trees.

On top of this, the leaf litter from pioneers (especially birch) helps enrich peaty soil and makes it better for trees. Remove the birch and the soil is less tree-friendly. And centuries of rearing and removing animals from the land, means that high concentrations of nutrients have been lost.

Trees draw up a huge amount of water from the ground, and release it into the air through their leaves and needles. When trees are cut down the ground can become waterlogged. This makes it hard for trees to return, especially when the seed source has been removed. It’s a vicious cycle.

 

Forest structure

Deforestation and overgrazing also have effects that are less visible. Sometimes we may see what looks like a healthy woodland at first glance, but a closer look reveals more.

Overgrazed woodland may have old trees but lack youngsters to replace them. They are also missing a healthy shrub layer and ground flora.

Not only have we lost woodland cover. Like humans, deer have their favourite foods. This means that some tree species suffer more than others. Aspen, holly, rowan and juniper are high on the menu, so they are often absent or scarce in the remaining pockets. Less tree diversity means less wildlife diversity.

 

A forest for the future

Humans have drastically denuded and degraded our woodlands over thousands of years. No one can say for certain what the forest would be like if we hadn’t been so heavy handed with it. But we can safely say that it would be much bigger and much more connected than it is now. It would also have a lot more wildlife. And it would bring with it countless benefits, including carbon storage.

So what is the future for the forest? Many native pinewood patches are still struggling to expand, or even survive, mainly due to overgrazing. Encouragingly, following the Second World War, the tide began to turn. People began to make more effort to protect our Caledonian Forest remnants. While there is still much to be done, there is now a huge interest in restoring native woodlands in Scotland with many organisations and individuals on board.

Trees for Life’s vision is to restore a large area of wild diverse forest, where people and wildlife can flourish. The aim isn’t to recreate a forest of the past since forests are ever-changing ecosystems. The goal is rewilding: restoring the key elements in the forest to allow natural processes a freer reign.

 

Written by Dan Puplett
With thanks to Dr Coralie Mills for revisions

 

Sources & further reading

Ashmole, P. (2006). The lost mountain woodland of Scotland and its restoration. Scottish Forestry 60 (1). 9-22.

Bain, C. (2013). The Ancient Pinewoods of Scotland: A Traveller’s Guide. Sandstone Press: Highland.

Fowler, J. (2002). Landscapes and Lives: The Scottish Forest Through the Ages. Canongate: Edinburgh.

Macdonald, B. (2019). Rebirding. Pelagic Publishing: Exeter.

Smout, T.C. (ed.) (1997). Scottish Woodland History. Scottish Cultural Press: Edinburgh.

Smout, T.C. (ed.) (2003). People and Woods in Scotland – A History. Edinburgh University Press: Edinburgh.

www.nature.scot/landforms-and-geology/scotlands-rocks-landforms-and-soils/landforms/ice-age-landforms/ice-age  (Accessed July 2020)