The deep past and possible future of the Outer Hebrides

The past is unpredictable. ~ Russian proverb

The history of Scotland’s modern forests began when the final phase of the last ice age, the so-called Loch Lomond Stadial, came to an abrupt end about 11,400 years ago (9400 BC). By the end of the last ice age most of Britain was a tundra landscape, an almost treeless vegetation type characteristic of the Arctic region. This landscape looked very much like that found in present day Lapland, Alaska and northern Siberia, with many herbs, low shrubs such as willow, dwarf birch and juniper. Over the course of just a few decades the climate warmed to temperatures probably greater than today, making Scotland suitable for the growth of forests of trees. When the temperature rose, trees such as hazel, birch, willow, pine and aspen relatively quickly replaced the tundra vegetation. Once established, the newly formed woodlands changed rapidly in appearance when the hardy pioneering species were joined by late succession species, migrating more slowly, lagging behind the climate change. These trees spread from the European continent, which was still joined to the British Isles by a land bridge, and through southern England. The process was gradual and deciduous trees such as oak, elm and alder arrived in Scotland only between 8,500 and 8,000 years ago (6500 and 6000 BC).

Scots pine, the only conifer species that established itself in Britain after the last ice age, first appeared, surprisingly, in the northwest of Scotland around 9,000 years ago (7000 BC). It probably came from isolated populations in a now drowned ice-free area to the west of mainland Scotland. From there it spread across the Highlands as far South as the northern tip of Loch Lomond and Rannoch Moor. The pinewoods of South-west Scotland probably originated from populations invading from Ireland.”

~ from “Conquering the Highlands” by Jan Oostheok

A Stadial is an era of cold climate when ice sheets grow across the land. The ice sheet in the Loch Lomond Stadial was apparently centred over Rannoch Moor, and spread outward from there in a time also known as the Younger Dryas. The dryas is a little tundra plant. 20th century scientists trying to understand what happened across the north in the last Ice Age found the dryas disappeared from areas of Scandinavia as the world warmed ~ by 15,000 years ago it seems the northern climate was almost the same as in the 20th century ~ then began to grow again in the same areas as the climate reversed around 12,800 years ago. The north experienced a cold era lasting about 1,200 years. Ice resumed its grip on the western highlands south as far as Loch Lomond. The Loch Lomond Stadial or Younger Dryas ended even more abruptly than it started. Average temperatures, measured in micro-analysis of ice cores from deep in the Greenland ice sheet, apparently soared 10°C in less than 50 years (!!!) ~ a last vicious twist in the Ice Age which apparently finished off the mammoths, woolly rhinos, giant elk, giant beavers and sabre tooth tigers in the future British Isles. But not Scots pines, in their mysterious western refuge from which they now spread across a vacant northwest highlands of Scotland.


1Nothing in science about the past or future climate can be considered finalised. For now, the paper where I found these maps presents the state of the art, the best guess about the collapse of an ice sheet which once covered almost the entire future British Isles.

The maps show continuous ice once stretched from Norway, filled the future North Sea, covered all mainland Scotland and its northern and western isles, and reached out west of the outer Hebrides, even west of the St. Kilda islands which are now over 60 kilometres west of the outer Hebrides, on occasional fine days visible from where I sit on the west coast of the Isle of Harris.

It is estimated that from around 27,000 years ago, for thousands of years the ice covered the mainland east of here up to 1,000 metres deep. It also filled the Minch, the sea channel now between the outer Hebrides and the inner isles and mainland.

18,000 years ago, shown in the first map (lower right), ice still stretched all the way to Norway.

17,000 years ago (upper left) the ice sheet was no longer connected to the ice covering Norway. It still covered most of the future British Isles, which would remain connected to mainland Europe about another 9,000 years.

16,000 years ago (upper right) the Ice had shrunk massively. What would far in the future become England, Wales and Southern Ireland were free of yearlong Ice. It appears there may have been a narrow corridor up the west coast for life to move north as far as the future Hebrides, then still connected to the mainland as the sea was far lower than now. The west coast of Britain was in reality some distance west of where it is shown on these maps.

15,000 years ago (lower left) all the west coast of Britain and future Hebrides were free of permanent ice and snow.

This graph comes from a Wikipedia article entitled "Meltwater Pulse 1A.

This graph comes from a Wikipedia article entitled “Meltwater Pulse 1A.

The graph based on analysis of coastal sea beds around the world shows rising global sea level since around 22,000 years ago, when the global ocean was at its lowest level in the last Ice Age. Colossal quantities of the planet’s water were locked in ice and snow on land. The ocean surface was 130 metres lower than now. The graph line is without doubt a lot smoother than the reality was in those thousands of years as the massive ice sheets came apart and the climate experienced spikes like the Younger Dryas.

The British and Irish ice sheet at its maximum apparently accounted for just 4 metres of global sea level.

15,000 years ago, sea level was about 110 metres lower than now. The ocean would soon commence a thousand years of rapid rise, with an apparent surge during that time when the sea appears to have risen 20 metres in less than 200 years ~ over a metre every ten years ~ or even faster.

We do not know what caused it. The sea rose far too fast to build coastline structures. The Wikipedia article is called meltwater pulse 1A, suggesting the surge in sea level was caused by collapse of an immense ice dam on a continent somewhere, releasing a gigantic reservoir of accumulated meltwater into the sea. We do not know that was the cause, or the only cause.

The Ice sitting on the continent of Antarctica now contains enough water to raise the global ocean level 70 metres if it all melts. 40 million years ago the Antarctic ice sheet was not there. The white cliffs of Dover were in construction, a giant coral reef. A few miles from here is a Dawn Redwood, a metasequoia tree planted around 65 years ago. It is an ancient kind of tree, a deciduous conifer, one of the first deciduous trees on the planet when it came into being around 200 million years ago. This one makes little female cones, but cannot produce male cones, so is not fertile. The climate here is too cool, at 58°N in the outer Hebrides west of Scotland. Fossil remains have been found showing that 40 million years ago this tree was present, so was fertile, at 80°N. They probably grew at 80°S as well. Since Antarctica was long ago scoured down to bare rock by the slow moving Ice, and its soil and everything that grew in it dumped in the sea, we cannot be sure about that.

15,000 years ago, we can guess that the ice sheet on Antarctica was more massive than now. Given the immensity of water released into the ocean to raise the global ocean as much as fast in the next few hundred years as the graph above shows, it is likely that colossal changes were occurring on Antarctica. It is hard to know. Colossal chunks of ice might have broken up, slid into the sea, raising the ocean instantly without having to melt first, then melted into the ocean, and vanished, leaving very little trace of the event.

Intense fieldwork being done now in the far northern Arctic Ocean has found evidence in the remains of tiny marine organisms sensitive to temperature change to suggest that in the Ice Age, the sea for tens of thousands of years under the massive northern ice sheet was slowly warming, as geothermal heat from the planet’s interior radiated up through the seabed. Under the titanic structure of the sea ice shelf in that time the sea was unable to lose this heat. In a gradually warming planet emerging out of the coldest depth of the Ice Age, a slowly warming sea working on a slowly weakening ice sheet eventually caused the structure to fail.

Massive structures, ice sheets or empires, have a tendency to remain apparently unaffected by changing conditions around and inside them for a long time, then abruptly fail in spectacular fashion. In the north and in the south, as the empire of the Ice came towards its end, something spectacular certainly happened.

Whatever it was, it discharged into the ocean a quantity of water many, many times bigger than the entire British and Irish ice sheet. For life on sea coasts it was cataclysmic. For anyone living on an island coast, the end of their world.

15,000 years ago, before this surge in the sea level, the permanent ice was gone from the west coast of Scotland, the sea more than 110 metres lower, the climate for a few hundred years similar to now.

This comes from a chart in the online archive of the National Library of Scotland ~ A new and improved chart of the Hebrides. or Lewis Islands and adjacent coast of Scotland…

This comes from a chart in the online archive of the National Library of Scotland ~ A new and improved chart of the Hebrides. or Lewis Islands and adjacent coast of Scotland…

This map was printed in 1804. I apologise for not presenting a more recent seabed survey map. Such things are not floating around for free, at least not where I have been looking. In defence of this map, I will say that two centuries ago, without radar or GPS or any pre-existing Admiralty surveys of this area, sailors had a vital interest in mapping accurately the seabeds they were travelling over.

It shows an extract from the results of a survey of the sea channel, the Minch, between the island of Skye, seen on the right, and the island of Harris and Lewis, on the left. In between are the Shiant isles.

The figures are soundings of the sea bed, taken by dropping a lead weight on a marked rope. The depths are shown in fathoms. A fathom is 6 feet, 1.8 metres.

A line can be drawn from Skye to Harris passing south of the Shiants where only in a narrow trench between the Shiants and Harris does the depth appear to reach 58 fathoms, just less than 105 metres.

Glaciers descending out of mountains crushed and shattered by 50,000 years of Ice carried down rocks, gravel and silts into lower ground, where rain and meltwater washed the gravel and silt down further, into the lowest ground.

So the trench between the Shiants and Harris would have been partly filled with silt, gravel and sand. It would be carved deeper when the sea rose in the next few hundred years and tidal currents began to run through, and carry the sand, silt and gravel away.

For a few hundred years, maybe a thousand years, before and after 15,000 years ago, the way was open for life to move on land into what are now the outer Hebrides.

Life such as pine trees. Pine seeds are light enough to have blown across a narrow stretch of water, but I think they did not have to.

I have lived on the west coast of Harris since June 2011. It’s now July 2015. So far, I have seen the driest three months ever recorded, wettest early spring, driest September, lowest atmospheric pressure ever measured in the British Isles, strongest wind ~ in one of the windiest places in the world ~ and now the coldest, greyest, wettest May, June and July recorded in around 150 years of meteorological measurements. It’s been an interesting time to plant trees on a windswept coast overlooking the north Atlantic, in which for over six months now have been taken some of the coldest temperature readings ever recorded there. Every time the wind blows from the west, we feel it.

We have planted almost 4,000 trees here. They’re not growing fast, but they survive, and I know from experience of planting trees on the mainland coast about 100 kilometres east of here that in time, with luck, they will accelerate.

The point of this autobiographical reminiscence is that I have seen trees in some exposed west coast locations survive some rapid climate fluctuation.

I am also the gardener at Amhuinnsuidhe castle near here. There, I see what is possible on a coastal site facing the open Atlantic in the outer Hebrides. Take a look ~


In 2012 it hardly rained here in four months. Lochs and streams dried up all over the island. I never watered anything in that garden. We collected buckets of redcurrants and blackcurrants. The following year the early spring was so dry moorland fires were breaking out in March and early April here, on Skye and on the mainland. Then the weather changed gear. May was brutal ~ gales, hail and rain, so grim hardly a leaf on Harris dared peep out before June anywhere but in the castle garden. There, spring rolled on, flowers and leaves came out, birds sang …. never underestimate the determination of life to live or the power of life to shape an environment.

The island of Harris and Lewis covers 2,179 square kilometres (841 sq.miles). Photographs from early in the 20th century show it was almost devoid of trees outside Stornoway and a few places like Amhuinnsuidhe, where the castle was built in 1867. Almost all the garden was vegetable and flower beds until after World War II. The mighty beech which fills most of the shot immediately above must be over 70 years old, but most of the trees in these photos were planted after World War II.

Most of the rest of the island is still treeless. The two photos below were taken about 500 metres from the castle ~


The last two photos are more characteristic of most of the island today.

Amhuinnsuidhe garden contains some exotic species coexisting with the native beech, oak, rowan, birch, willow, alder, pine, bramble and gorse. Still, I think it is in the garden we can more accurately picture the reality of 8,000 years ago.

I have a friend who’s lived here a lot longer than I have. In past years, he has told me, digging out peats for winter fuel with other crofters at Bowglass, on the shore of a sheltered inlet on the east coast of Harris, they often found chunks of ancient pine. On our croft, and on the mainland west coast, a little more than a metre down in the peat is found an interwoven mat of birch so well preserved you can tell from the bark it is birch. But my friend was sure this was pine ~ sometimes they would smell the pine resin. He told me a visiting expert a few years ago assured him pines were not native here, and was not minded to go take a sniff for himself.

So what is native to the outer Hebrides ? What does native mean ? I am not aware of a settled definition of that. So let’s say we are asking what lived here 8,200 years ago, when the still rising sea was separating the southern isles, the Uists, from the long northern island of Harris and Lewis.

It is an uncertain picture, and impossible to look into it without stirring some controversy.


The same friend has told me he used to know a Harris man, now dead, who told him he used to see pine martens here. Early in 2013 an officer of SNH (Scottish Natural Heritage) based in Stornoway told me pine martens are not native here ~ any recorded sightings by local people were “merely anecdotal”. So I was interested to read in a recent SNH publication the following ~

To confuse matters further, the fur of medium sized mustelids such as pine martens was highly valued in Mesolithic times, and also by Viking travellers, and it is highly possible that live animals were moved around and introduced to novel regions across Europe to provide a trappable fur. This may well be the source of some of the historic Scottish island populations such as that recorded in the Outer Hebrides, with the Isle of Lewis being the closest point to the Scottish mainland at a distance of approximately 33km. Martens became extinct here in 1875, most likely as a result of game keeping activities (Langley and Yalden 1977).”

Roy, S., Milborrow, J., Allan, J. and Robertson, P. 2012. Pine martens on the Isle of Mull – Assessing risks to native species. Scottish Natural Heritage Commissioned Report No.560. Published in 2014.

I can only admire the writer’s familiarity with the fashion sense of Mesolithic people who lived over 7,000 years ago, spoke a language we do not know at all and have left us no images of themselves. No scrap of their clothing has ever been discovered. Anyway, apparently SNH do now accept that pine martens once lived here.

Deborah Anderson is an archaeologist, also based in Stornoway, employed by the government of the western isles (Comhairle nan Eileanan Siar). She has for several years worked in the outer Hebrides. She told me in a dig on South Uist in an Iron Age site containing evidence from 2,000 to 3,000 years ago, the bones were unearthed of a pine marten.

The sea separated the southern outer Hebrides islands ~ Berneray, North Uist, Benbecula, South Uist, Eriskay and Barra ~ from the northern isle, Harris and Lewis, about 8,200 years ago. The car ferry from Harris to Berneray threads a course between buoys past the reefs, skerries and islets over a shallow sea bed where people and maybe pine martens once walked.

The Vikings appeared less than 1,400 years ago. Pine martens may have been here long before, and when the sea rose to divide the islands, lived on in the Uists and here in Harris and Lewis ; also possible they continued to live here beyond the date of their official extinction determined by landowners’ estate records, basically records of what was killed. Back then, tenants of the estates, the native people of the island, were not allowed to kill so much as a rabbit, even one munching through their crops, even if their families were going hungry as they too often did. A man who has spent his life here once told me of an eighteen year old man who shot a rabbit in South Harris in the 19th century to feed his family, was arrested and flogged for it and died of his wounds. So there may be some lack of clarity in who killed what when not long ago on these islands.

I was recently talking to a gamekeeper on Skye. About thirty years ago a bridge was installed connecting Skye to the mainland, and now Skye has a growing population of pine martens. He told me the old estate shooting records of Skye make no mention of pine martens. He had investigated the records to find if they contained evidence the pine marten can be called native to Skye. Finding no such evidence he contacted SNH to ask if they had any plan to stop the spread of pine martens on Skye. They do not, and as long as the bridge is there I don’t see how they could if they want to. Pine martens have come back into some favour recently after centuries when they were considered pests to be exterminated. It has been seen in areas where they are reintroduced in Ireland that the red squirrels return. It turns out the grey squirrels who had been pushing out the red squirrels are too big and heavy to get far enough out on branches of trees to evade the pine martens. The red squirrels are lighter, and can move on branches too thin for the pine martens to follow them. Whether there is evidence to show the red squirrel lived on Skye in the past so SNH can permit their reintroduction, or we just have to wait for them to cross the bridge, I don’t know.

The absence of pine marten from the old shooting records on Skye, while they appear in old records up to 1875 on this island, might mean one of several things ~ such as, the Vikings on Skye did not import pine martens to farm them for fur ; they didn’t share the taste for wearing it, or they got their marten fur from farms elsewhere ; or, they farmed pine martens on Skye but didn’t allow any to get free ; or, pine martens were farmed on Skye, got free, but were hunted to extinction before records were kept ; or, pine martens reached Skye naturally when it was possible to get there overland, around 15,000 years ago, and some moved on west and found their way to this island, then the sea rose around this Western Isle and around Skye, then came the Younger Dryas. On Skye, nearer the mountainous coast of the mainland, the climate got too severe for pine martens to survive. On this larger Western Isle further out the severity of the Younger Dryas was tempered by the surrounding ocean, and pine martens survived along with the pines.

Deborah Anderson has also participated in digs in Mesolithic sites from a time before sheep, goats and settled agriculture, when people moved on the sea through the islands and along the mainland coast with the changing seasons. The digs have brought to light the earliest so far found evidence of human presence out here, on the west coast of South Harris, about 9,000 years ago. Bones of a red deer have been found here of about the same age. In several sites over 7,000 years old, bones of hares have been found.

Red deer and hares are conventionally thought to have been brought out here by humans. Again, it is possible. Looking today at over 20 kilometres of often rough sea between Skye and the outer Hebrides you could see why such a convention exists. But for the same reason we might think it strange for people in small boats 9,000 years ago to bring out here enough red deer to form a viable breeding population. A stag can weigh over 120 kg, and might not have been in total agreement with the strategy.

Those people appear to have moved from place to place through the year, roasting big stores of hazelnuts for winter protein, having access to a wealth of sea life and bird life we can only imagine, knowing where, when and how to get deer or hare meat if they wanted it. And I find it hard to understand how they would manage to keep their deer once they brought them out here ~ the modern specification for the height of a deer fence is 180 cm. If they released them into the vastness of a wooded island, they would be lucky to ever see them again. Bones of deer and hares here 9,000 years ago might simply mean they were already here when people arrived.

A slow worm in Amhuinnsuidhe castle garden, July 2015.

A slow worm in Amhuinnsuidhe castle garden, July 2015.

Slow worms are welcome in the garden. They eat slugs. I hardly ever see a slug there. They are seen in the moors around here, and can live 30 years. The females give birth to live young, traditionally in September. They usually hibernate from October to May, although in the fine early spring of 2013 I saw a young one in early April.

Slow worms can swim, not very well. At least they can survive in water until they cool too much to get out again ~ they are cold blooded. I find it hard to believe they crossed much sea to get here. We have to imagine a pretty far fetched series of accidents ~ with slow worms even more than deer and hares, you see the attraction of invoking a human agency to get them here after the sea rose around us. I do not know a conventional explanation for their arrival. Alternatively they could have travelled on land, spending many generations on the journey, after the ice sheets were gone, before the sea rose, before the Younger Dryas, accompanied by the mysterious pines. So could they have survived the Younger Dryas here ?

The other night here, in the last week of July, the temperature fell to 5°C. So far this year we have yet to hit 20°. It has been a special occasion when we reach 15°. Yet I have seen more slow worms in Amhuinnsuidhe garden than in the previous three years. Maybe it’s too cold for them to move fast enough to hide … maybe the moist cool weather has made it a good year for the slugs and worms they eat.

This summer of 2015 is being called the coldest, greyest, wettest in the outer Hebrides since 1816, a year notorious across the northern hemisphere. I was once shown in a graveyard in Vermont in northeast USA many headstones carrying the date 1816. Nobody in the north knew it then, but the cause was Mount Tambora. It erupted in New Zealand in 1815, the biggest volcano on Earth in the last 10,000 years. On the shore of Lake Geneva in late spring, 1816, in a house rented by Lord Byron, Mary Shelley wrote Frankenstein. The weather was too foul to go out. It captures the mood of the year. The slow worm survived it.

Before that, through several hundred years cooler than now, with occasional plunges into winters when people gathered around bonfires on the ice on the Thames in London, the slow worm survived.

Around 3,020 years ago another huge eruption, Hekla on Iceland, had drastic effects in the British Isles. Analysis of old peat layers in Caithness has shown 25% of the pollen blown into the peat just before the eruption was pine. A few years later it was 4%. Across the British Isles thriving industries forging tools for agriculture appear to have suddenly shut down, then after a few years picked up again, making weapons. We were in the age of the hill forts, and in the Highlands and Islands massive stone brochs, and the emphasis in agriculture had shifted from crops to animals. Analysis of peats here has suggested 3,000 years ago most of the trees were gone from this island. Hekla was another in a series of big bites taken at the forest by human activity and deteriorating climate. The slow worm lived through it.

Around 8,200 years ago, the vast continental ice sheets were melting back. It appears an immense lake of meltwater in central North America was contained by the Ice. The ice dam broke. The contents of the lake gushed into the North Atlantic, carving out the St Lawrence seaway and messing up the Gulf Stream. The average temperature in the British Isles seems to have dropped over 3°C in around twenty years. Sea level surged over 2 metres, contributing to the division of the outer Hebrides into the several islands that exist now. The effects on land life and human cultures have been observed as far away as the Black Sea and Mesopotamia. The cold spell lasted over a century. By the time it was over more than 20 kilometres of sea separated the outer Hebrides from Skye.

We can’t rule out the possibility slow worms were brought here. About 35 years ago frogs were brought by humans to the isle of Great Berneray, connected to the west coast of Lewis by a short road bridge. The frogs hopped over that bridge years ago. I’ve seen one in the long grass near Carloway several kilometres from it. Another bucketful was later released on Harris. Slow worms could have been imported for the same reason as the frogs, to eat slugs, maybe even in the last 200 years and no one recorded it. DNA analysis could throw some light on it. DNA recently sampled in Ireland of stoats and otters is generating an intense reexamination of Ireland’s deep past, suggesting they have been separated from stoats and otters on the British mainland far longer than previously thought. The same methods could tell us how long the slow worms of the outer Hebrides have been here, and others such as hares.

An animal which would naturally follow hares overland is the wildcat. The wildcat was driven to extinction in Ireland within human history. Officially, the wildcat has never lived in the outer Hebrides since the Ice Age. I know two men about 50 years old who have lived their lives in Harris. Both recall that they were told as they were growing up of sightings of wildcat here by the people telling them. (Merely anecdotal.)

In 1936, about 10 km down the west coast from the island’s northern tip, the Butt of Lewis, an archaeological dig in an Iron Age site thought around 1,500 years old found a fine bronze dagger, some broken pottery and other remains. Among them was something identified by a member of the team as a wildcat rib bone. The dig was led by a Mr Baden Powell. The dig report states that all animal bones were boxed up and sent to the Royal Museum of Scotland in Edinburgh, now the Scottish National Museum. Neither I nor Steve Piper, head of the Scottish Wildcat Association until that organisation disbanded a couple of years ago, have yet interested anyone with access to the museum in going to look for the box.

Where slow worm, pine marten, red deer and hare could go, the wildcat could certainly go. Whatever they could survive, the wildcat could, apart from human persecution which has targeted the wildcat until they are now on the edge of extinction on the mainland and may have reduced them here until they survive only in a few feral cats interbred with domestic kitties. Pine martens are apparently extinct on the island. Red deer DNA might have been diluted by deer brought later to increase the numbers available to hunt. Slow worms and hares are the most likely to have existed as separate populations without later additions from the mainland, and analysis of their DNA could tell us how long.

Another enigma present here in the 20th century, now locally extinct, is the ptarmigan. Ptarmigan can only fly a few metres at one go, their stubby wings whirring just above the ground. How or when they got here is also unknown. Again, it is possible someone with a taste for ptarmigan meat brought them.

The other mammals of the outer Hebrides are the otter, brown rat, pygmy shrew and in the Uists the vole, and many thousands of rabbits, who certainly arrived here within the last thousand years with human assistance. The first recorded sighting of brown rats in England was in 1730, about 200 years after the first sightings in mainland Europe. So the rats and rabbits are recent arrivals.

The pygmy shrew and otter lived in Ice Age Europe south of the ice. The otter, like the red deer and wildcat, could have swum some distance to reach this island when the sea was lower, the crossing from Skye narrower than now. The pygmy shrew could not.

Given its tiny size, we might think the pygmy shrew could easily have come unnoticed in boats in sufficient numbers to get a breeding population going here. On closer examination it doesn’t look quite so easy. They live on small insects and invertebrates and have one of the highest metabolic rates of any animal. They have to eat every two hours. So first the boat would have to have something to tempt them aboard, or the boat would have to be getting loaded with something containing shrews hidden in it, there would have to be food for them to eat during the crossing, then they would have to get safe ashore, then find another shrew who had made the same journey and stayed in range to mate with. They would have to do all that, giving a female time to raise young, in a life span of 15 months. A pregnant female might have made the crossing and so given the whole process a head start, but as a way of getting a viable breeding population of pygmy shrews here it is at least debatable.

The presence of voles in the causeway-connected chain of the Uist Islands but not on the isle of Harris and Lewis suggests they arrived in boats after the sea came between us 8,000 years ago. It was easier for them than for shrews, since voles can eat plant material and are not under the same pressure to top up every two hours. Yet it cannot have been all that easy, since they never made it to Harris and Lewis. The pygmy shrew does live in the Uists. So it has either made it on separate boats to both the northern and southern outer Hebrides, something the vole has so far failed to do, or the shrew was here before the sea came between us.

So on the island along with birds and insects 8,200 years ago we might have found ptarmigan, otter, pygmy shrew, pine marten, hare, red deer, slow worm, wildcat, and probably others who later became locally extinct. What about trees ?


The determination of life to live. In the foreground of this photo, on the west coast of North Harris, one of several juniper of uncertain age within 300 metres of our croft. What changes they have seen in their local environment I can only guess.

The determination of life to live. In the foreground of this photo, on the west coast of North Harris, one of several juniper of uncertain age within 300 metres of our croft. What changes they have seen in their local environment I can only guess.

The convention regarding trees on the island is that there never were many on the exposed west coast. The continuous mat of birch remains in the peat on our croft suggests otherwise. And since we fenced around our croft, we see willow rising here and there out of ground previously nibbled to a carpet by sheep. In a sheer crag inaccessible to sheep and deer is a rowan. Until we moved in there was no other rowan within two kilometres in any direction.

“Perhaps the most noticeable feature of this diagram is the consistently high value for hazel This and the generally high birch values indicate that these two trees formed the main woody

vegetation of the island. At different times other trees appeared in response to varying conditions: in the early part of the diagram pine and elm are important and later alder and oak. Lime is absent throughout, though it has been found in minute quantities in peats both to the north and south. Beech pollen, again missing here, has been found in the peats from the Islands of Rhum and Soay, and Erdtman (1924) recorded it from the Island of Lewis… The very few grains of willow occurred sporadically and have not been graphed.”


Janos Erdtman, from Sweden, has been called the father of palynology, the study of pollen blown on ancient winds and dropped in places where it is preserved. One of these places is peat. Every year a layer of vegetation dies and subsides into a wet oxygen-poor environment where it cannot totally decay. Mineral content is leached from it and it gradually compresses inside its own weight, becoming colourless and translucent at first then compressing further into the dark carbonaceous fudge of peat. It has been calculated it takes around 300cm of vegetation to make 30cm of peat. If a later shift in local conditions causes that peat to be covered in mud or sand or clay, and that to be later covered in more mud etc., so the peat is buried deeper and deeper, in time 30cm of peat can make 3cm of coal. In the process, scraps of the materials of life get buried inside the peat. Pollen can be surprisingly durable in such a setting.

Another place where palynology can yield fascinating insights into the deep past is in sediments of mud washed by streams into lakes and settling on lake beds. Mud cores from lake sediments in Ireland have yielded evidence from a time before the peat beds formed ~ as far as I know, no one has yet undertaken any such work in any of the thousands of lochs in the Hebrides.

The quotation here describes work done in Barra, the southernmost of the outer Hebrides.

The Barra peats show something later explorations would confirm. There used to be a lot of hazel and birch in this part of the world.

We see from the study on Barra that pine is found in the lower depths of the peat. More surprising is elm and oak, while rowan is absent from the Barra peats, along with juniper and other plants we might have expected to see. Why, I don’t know. Why so little willow pollen, I don’t know.

It shows that in the ancient peat samples absence of evidence may not be evidence of absence. It was long thought alder was a relatively recent arrival in Ireland. No sign of alder had come to light from before 7,000 years ago. Now it appears alder was present on Ireland at least 4,000 years earlier, in tiny refuges waiting for a damper climate, then by 7,000 years ago was spreading.

So to find pollen of a particular species in tiny amounts might not mean it was a recent arrival, or that there had never been much of it around. And samples from peats cannot tell us what was here before the peats, or for how long.

Kathleen Blackburn’s paper does not attempt to estimate the age of the pollen samples or the rate at which the peat had accumulated over thousands of years.

The quotation that started this essay says “trees such as oak, elm and alder arrived in Scotland only between 8,500 and 8,000 years ago … trees such as hazel, birch, willow, pine and aspen relatively quickly replaced the tundra vegetation” at the end of the Younger Dryas 11,400 years ago.

I would say the same could have happened before the Younger Dryas.

The appearance of the first pines in Scotland in the northwest, from where they spread south after the Younger Dryas, has been noticed because further south at the same time they were not spreading. In the car park at Stonehenge are three concrete manhole covers. They protect three post holes, fragments of wood discovered in careful archaeology of the site just before the car park was made a few years ago. The posts were pine poles, carbon dated 10,000 years old, apparently set on astronomical sight lines at the future Stonehenge.

Yet no evidence has been found of pines in Wales 8,800 years ago. A forest of broadleaf trees was marching north, too thick for pines to travel as far as from Stonehenge to Wales in a thousand years. Instead they were dwindling away in southern Britain.

So their appearance in strength in northwest Scotland is conspicuous.

On the other hand, if a broadleaf forest advancing north encountered some of the same trees spreading south it would be less easy for us to detect 9,000 years later, especially if we are not looking for it.

Apparently pines survived the 1,200 year cold spell somewhere near here. It is not so hard to imagine that other trees survived as well in that Younger Dryas Avalon, and some animals who lived among the trees.

Oak, elm and beech all had an advantage in the move of the trees north. The west was unlocked from the Ice first, and winters are unusually less cold in the west of the British Isles than further east. It is not unusual in winter for the outer Hebrides to be now and again the warmest place in the British Isles. Oak, elm and beech can tolerate the winds and salt of the coast. Elm for example is highly salt tolerant, and can grow in soils across a range of pH values.

I have seen stands of oak and beech of considerable age on exposed west coasts of the Hebrides. I remember an oak wood on the west coast of Mull clad in a continuous cloak of moss, low growing and tangled, a continuous bristly canopy over it all, scraps of wool caught in its branches. Sheep were being allowed to get amongst the trees. No young trees were growing.

How long have these trees been in the Hebrides ? Keep in mind that in a totally healthy forest you rarely find ancient pollen. What life is producing, life digests and recycles into new life.

The vegetation changes to be described refer to the area from which the regional pollen was derived, though it is uncertain whether this includes just Canna or also other islands and parts of the mainland. The earliest vegetation indicated in the 1963 diagram showed a strong dominance of Gramineae, though Pinus, Betula and Salix were present. Unfortunately the tree pollen frequencies are too low to allow the relative proportions of Pinus and Betula to be assessed. In the period represented by 402-365 cm, however, it seems likely that Betula was declining in favour of Pinus. Occasional grains of Ulmus and Tilia are probably contaminants.

In the following period (represented by 355-335 cm) the area possibly carried a scrub of Salix, Corylus (or Myrica) and Rosaceae, with an undergrowth of Polypodiaceae and Gramineae. The majority of trees present were probably Pinus. Less common were perhaps Betula and Ulmus. Quercus and Alnus were possibly also present.”

“Pollen analysis of peat from the island of Canna (inner Hebrides)”  R. Flenley & M. C. Pearson 1966

Canna is a small island south of Skye, not far from Barra. The authors of this study from 1966 also say “Palynological investigations in the inner Hebrides are restricted to those of Erdtman and Blackburn”.

Kathleen’s Blackburn’s study on Barra and her reference to Erdtman on Lewis both relate to peat samples taken in the outer, not inner Hebrides. I don’t know of any other work she did in the islands. I guess by 1966 no one else had taken ancient pollen samples anywhere in the Hebrides.

Betula is birch. Corylus ~ hazel. Pinus ~ pine. Salix ~ willow. Alnus ~ alder. Quercus ~ oak.  Rosaceae are a large family including wild rose, wild cherry, strawberry, raspberry and more.  Polypodiaceae are ferns. Gramineae are grasses.  Ulmus is elm, Tilia is the lime tree, not the one that gives us citrus fruit.

The authors don’t explain why they thought elm and lime pollen in their samples were contaminants, meaning I guess they did not think the pollen actually came out of the Canna peat. They seem to be admitting they might have been sloppy in handling their peat samples, in which case anything in them could have been contaminants. Yet it is a remarkable coincidence if their ancient peat was contaminated by two kinds of pollen others have found growing in the Hebrides long ago. Maybe they did not trust their own work when it turned up something they did not expect, even though they refer to Kathleen Blackburn’s work twenty years earlier. She wrote of elm and lime pollen in ancient peats in the Hebrides, as we have seen.

The investigation on Canna like Kathleen Blackburn’s work on Barra did not attempt to estimate the age of the pollen they found.

By the time “A buried wall in peatland by Sheshader, Isle of Lewis” by P J Newell was published by the Society of Antiquaries of Scotland in 1988, radio carbon dating was available to estimate the age of peats and organic materials found in them. This study tried to discover the age of a buried stone wall near Stornoway. Here is what they came up with ~

ScreenHunter_02 Nov. 06 15.04

So peat at about 40cm depth is dated about 620 years old ; at 120 cm depth, about 1,760 years old ; at about 178 cm depth, 4,070 years old.

They find the rate of peat accumulation faster in the more recent past. I guess this may have to do with gradual compression of the older peat. In the peat over 3,000 years old they see a greater uncertainty.

Here on our croft, if the birch now about a metre deep was covered with peat on average 1cm every 30 years, which is within the range shown above, that could explain the death of the birch and a change from birch forest to a peat bog as a result of the Hekla eruption just over 3,000 years ago. It would mean the peat on the east coast of Lewis analysed in the study above accumulated faster than here, I guess as the vegetation that made the peat grew faster. All that is possible.

I don’t know, and I don’t know anyone who knows. Anyone who wants to take a sample of the birch for carbon dating is welcome. I have seen the same kind of mat of birch twigs, branches and bark at about the same depth in peats on the mainland coast about 100 km roughly due east of here.

The deepest peat I know anywhere in the Hebrides is in Barabhas moor, in the centre of Lewis. It reaches 9 metres deep. How old is that ? I can’t say. No one as far as I know has ever investigated the peat in the bottom of Barabhas moor.

Peatlands: Evolution and Records of Environmental and Climate Changes” edited by I.P. Martini, A. Martinez Cortizas and W. Chesworth tells us ~

“Long term average rates of peat accumulation can be calculated using the radiocarbon dates of the basal peat and the thickness of the peat deposit (assuming the surface of the deposit represents the current date). When this method was used, the average rate of peat accumulation for the Sub-Arctic was found to be 3.75 cm/100 yr. (25 samples) and for the Boreal 6.35 cm/100 yr. (35 samples). Zoltai et al (1988b) reported an average accumulation of 6.40 cm/100 yr. for Boreal peatlands …. The rate of peat accumulation is not uniform over time … for example the peat accumulations for the five Canadian peat deposits … show variations of several centimetres per 100 years between the peat layers … The average rates … were 6.76 cm/100 yr. for Nichols (1974), 2.07 cm/100 yr. for Ovenden (1982), 3.22 cm/100 yr. for Nichols (1967), 5.18 cm/100 yr. for MacDonald (1983) and 4.04 cm/100 yr. for Nichols (1969).”

The authors here go on to give deposition rates for Siberian peats ranging from 6 – 9.1 cm per 100 years.

The Wikipedia article on peat says an accumulation rate of a metre/1,000 years (10cm/100yr.) is normal in this part of the world. Where their evidence comes from, I don’t know. All the above data shows slower accumulation than that.

The most famous place on the island, the monumental stone construct of Callanish, has stood over 5,000 years. It seems there has been more palynological concentration on that area. In “The cultural landscape : past, present and future” edited by Hilary H. Birks appears the following ~

finds of Betula and Salix wood to the north of Callanish and dated to 7980 +/- 55 and 9140 +/- 65 B.P. respectively (Wilkins 1984) prove the presence of these trees in the outer Hebrides at these times.”

And this ~

Around Callanish, it consisted of Betula, Corylus, Salix, Sorbus, and probably Populus with an understorey containing Lonicera, Melampyrum and ferns.” This was at some time between 9,000 and 4,000 years ago ~ the author does not say.

Sorbus is rowan. Lonicera is honeysuckle. Melampyrum is a flowering plant known as cow-wheat. Populus is aspen.

I can find nothing on the Internet on any ancient lake bed sampling in the Hebrides. From the mainland, this project in sediment sampling of a small highland loch is worth a look ~

The opening of the Holocene is clearly marked by the expansion initially of dwarf-shrub heaths, dominated by Empetrum and Juniperus, followed by the development of open birch woods with Populus tremula and Salix spp. Corylus avellana expanded rapidly at about 9800 BP along with Sorbus aucuparia. By 9500 BP the landscape around the lochan would have been a mosaic of birch and hazel woods with aspen, rowan and willows, and with an abundance of ferns and tall herbs. Small treeless areas may have persisted where soils were shallow, and where there were natural rock outcrops.

At about 7200 BP Ulmus arrived in the area, but it never became an important component of the local forest vegetation. There is no evidence from the pollen stratigraphy at this site to suggest that pine or oak ever grew this far north ( Birks, 1977, 1989), even though pine stumps occur locally in the Eriboll area. The natural woodland cover of this part of Scotland appears to have been primarily birch and hazel woods. At about 5800 BP Alnus migrated Into the area and expanded locally in wet sites near the lochan.”

~ from “Lochan an Druim” by H.J.B.Birks (1980)

Lochan an Druim is a small lochan, 25 metres across, near the village of Eriboll in Sutherland, in the far northwest of mainland Scotland. The opening of the Holocene was the end of the Younger Dryas.

Empetrum ~ crowberry, a dwarf evergreen shrub producing edible berries ~ and juniper were there soon after the land emerged from the Younger Dryas.

Rowan, aspen, willow, birch and hazel were present 9,500 years ago, the author says. Evidence of aspen so long ago in the northwest of the British Isles is interesting, because aspen today in the outer Hebrides rarely produces seeds. Our summers are not quite warm enough. There are stands of aspen surviving in some tough exposed locations. They send runner roots through the ground, and new aspen shoot up. Some stands of aspen I have seen must have survived like that a very long time. What they cannot do is spread very far very fast that way. It could be evidence of warmer summers long ago. In what is called the Holocene maximum it is generally agreed average temperatures in the British Isles were warmer than the 20th century, but that was around 6,000 to 5,000 years ago. The author here is placing aspen in the far north of Britain long before that, suggesting warmer summers at least some of the time ~ and maybe that they had not had to travel all the way from the far south of Britain after the Younger Dryas.

Pine is not found in the pollen samples, but there is evidence it was there. Oak pollen is not found. Elm is seen from about 7,200 years ago, although not much of its pollen is found. Here as elsewhere hazel and birch were the most common trees. Here as elsewhere, absence from the pollen record is not proof of absence from the land in that time.

Hazel, birch, oak, pine, aspen, alder, willow, elm, lime, rowan, juniper, honeysuckle, ferns, rose or wild cherry or raspberry, or two, or all of them. The ancient northern forest was not such a poor scrubby thing.

15,000 years ago the Ice left a northern landscape scraped to bare rock after 50,000 years of ice cover.

An immense ice sheet may look changeless and eternal. It is all in motion. The Ice on Antarctica has been in continuous occupation of that continent over 30 million years. The ice at the South Pole is 4,000 metres deep. It is being intensely scrutinised, intimately examined, obsessively modelled as we try to guess what it is going to do next, extensively sampled through ice cores which so far have given us a temperature and atmospheric carbon graph reaching back 800,000 years. We have not yet found ice on Antarctica older than that. The pole marking the South Pole is moved about 10 metres every year to put it back on the Pole. Left to itself it would travel on and reach the sea coast a few hundred thousand years from now at the current rate of movement of the ice sheet.

The northern Ice in the last Ice Age was moving, scouring and grinding what lay below. What was native in the outer Hebrides before the last Ice Age, over 70,000 years ago, we will never know.

The Ice left a landscape of bare rock smeared with rock paste, ideal for birch. I have planted birch on a disused coal mine waste heap in Yorkshire, where the nettles abundant in the farmland all around it could not grow. It was a grey clay hummock that cracked in dry weather, was greasy and slippery when wet. The weeds would not grow on it. The birch loved it. They grew from 60cm to over 4 metres tall in three years.

Birch seeds are tiny, almost weightless, designed to fly far. The first Norse and Gaelic settlers who arrived on Iceland around 1,200 years ago found a place empty of humans, filled with birch forest.

Travelling up the west coast of Britain, the birch flew ahead, then the rest followed. Squirrels transported nuts, pine martens chased squirrels, birds ate rowan and juniper berries, wild cherries and blackberries, and deposited seeds with a little dose of nitrogen fertiliser. Bears did the same, boars rooted around the forest floor, robins investigated what the boars turned up, shrews rustled through leaf litter hunting insects, voles ate anything they liked, slow worms slithered in the leaf litter and grass mopping up slugs, worms, caterpillars, spiders … alder and pine seeds dropped in … hares ate leaves, wildcats, foxes”m and lynx ate hares, red deer browsed on leaves in the forest, grass on the open ground, wolves hunted deer, voles and shrews were a handy snack for any predator who could get nothing better … the whole thing moved north and west.

Through hundreds of years this forest advanced, taking a variety of forms on high ground, low ground, wet ground, river and loch shores, sea coasts, crossing a variety of rock and soil types on the way through the future British Isles, the most geologically diverse land area its size on Earth.

The rock of the outer Hebrides, known as Lewissian gneiss, is about half as old as the planet. It does not erode easily ~ you can see scratches left by the Ice, and ripples in outcrops made when it cooled from its last melting about 2 billion years ago ~ but when it erodes it contains plenty of minerals. After the ice left, the vacant land 15,000 years ago was prime real estate for birch, then what followed …

The sea rose rapidly between 15,000 – 14,000 years ago. The Minch between here and Skye reopened. This was an island again, over 200 kilometres long, its west coast far west of the outer Hebrides now. There was another island further west. Only the peaks stick out of the sea now, the St. Kilda group, sitting on a seabed feature, the St. Kilda platform, about 80 metres deep. Around it the sea is 140 metres deep.

In the next 2,000 years the climate cooled, warmed again, then plunged into the Younger Dryas.




This paper describes an attempt to create and run a climate model which would produce results agreeing with geological evidence in the northwest Highlands left by the Younger Dryas. The map above shows the result, a visualisation by a computer model of the maximum extent of an ice sheet centred over Rannoch Moor. I guess it can be held responsible for gouging out Glencoe to its present formidable chasm.

The map shows only where the Ice was over 20 metres thick, so there was year long snow cover across more land than the shaded area here.

The outer Hebrides are chopped off just northeast of the Harris hills. It avoids the map depicting the outer Hebrides as they are now, which would be misleading. There was a huge island out here and another to the west. It is agreed this great Eilean Siar, Western Isle, did not disappear under a revived ice sheet.

Seven years after this paper was published, there is no agreement on what caused the Younger Dryas, or what caused it to end, and still some doubt on how its effects varied around the world. For example ~

The history of climate, vegetation and land-use since 22 000 BC has been constructed for the Horton Plains, southern central part of Sri Lanka. Xerophytic vegetation, i.e: dry forest, predominated until 16 500 BC, indicating weak south-west monsoon (SWM) rains. The upper montane rain forest expanded from 16 500 BC as a result of warming. A first period of strengthened SWM appeared at 15 500-14 000 BC (Semi-humid). A second period of strengthened SWM appeared at 11 600-10 500 BC (Humid). A weak signal of the Younger Dryas event was traced to 10 200-8900 BC.”

The emergence of early agriculture in the Horton Plains,central Sri Lanka: linked to late Pleistocene and Holocene climatic changes. R. Premathilake

Paper presented in the International seminar on the “First Farmers in Global Perspective’, Lucknow, India, 18-20 January, 2006

One thing they have never had to worry about in Sri Lanka is ice sheet formation. Sea level rise would be another story. At some time, Sri Lanka like this island was detached by a rising sea from its neighbouring landmass, India. Another big problem can be fluctuation in the monsoon. Sri Lanka contains thousands of lakes, most man made on the order of a king around a thousand years ago to hold enough water between monsoons. Evidence is coming to light that towards the end of their Cool Age,our Ice Age, in Sri Lanka as elsewhere attempts at systematic crop cultivation were undertaken, and were affected by the behaviour of the monsoon. According to this paper the Younger Dryas in Sri Lanka occurred 12,200 – 10,900 years ago, several hundred years later than in the north, and its effects were milder.

A theory that a meteor slammed into the northern Ice and kicked off the Younger Dryas might not agree with the evidence from Sri Lanka and elsewhere in the tropics. The world’s dreadful summer of 1816 followed a huge volcano in New Zealand in 1815. We could also expect the effect of a meteor to be fast and global.

In fact it seems the effect of the Younger Dryas was most severe, and happened earlier, in the north. That is consistent with a theory that it started and ended with abrupt changes in the northern ocean. It seems to be in human nature that we are most certain about things we cannot prove, and some people are certain they know what started and ended the Younger Dryas. I am not one of them, and it may turn out that more than one cause was involved. The Younger Dryas might come to be understood as a massive gear shift in the global climate engine. The coming decades might demonstrate the same thing without the assistance of a meteor.

One leading suspect to have started the Younger Dryas in the north no longer exists. Lake Agassiz was an immense lake in northern North America dammed in by ice sheets slowly melting as the Ice Age drew towards a close 20,000 – 10,000 years ago. At least twice, it appears the ice dam burst, and a huge gush of cold freshwater entered the North Atlantic, fanned out across the surface, floating above the denser salt water below, and interrupted the heat exchange system of the Gulf Stream. The last time was the event of 8,200 years ago. An earlier event may have kicked off the Younger Dryas. Yet recent geophysical study has failed to find the evidence in the land consistent with such an outflow at that time. There is evidence for an abrupt global sea level surge of 6 metres just before the onset of the Younger Dryas, and that could be consistent with cosmic debris slamming into the Ice. As far as I can see it is just too soon to be sure either way.

In 2015, Newfoundland, northeastern USA, Iceland, northern Scandinavia and Scotland are experiencing a very cold, grey, wet summer. The north Atlantic is unusually cold for some reason. A lot of study is going into trying to find out why. The leading suspects are the Greenland Ice, Arctic sea ice and the ocean current circulation system. Once again as climate scientists try to model the behaviour of the North Atlantic, we are playing catch-up. As far as I know, no one saw our chilly summer coming, or can tell us what is coming next. Meanwhile the planet as a whole experiences record heat.

On the Scottish mainland, the evidence suggests average temperatures in the Younger Dryas 8-10° lower than now. That would have been severe. The relatively small ice sheet that formed in the east Highlands suggests it was drier than now, especially inland, the difference between winter and summer greater than now ~ winters far colder, average temperature through the year less than zero. But the summers perhaps not much cooler than now, so snow at lower altitudes inland could melt.

The Younger Dryas in the outer Hebrides might have been different again. Our summers today are cooler than the mainland, winters not as cold. The surrounding ocean tempers our climate. An announcement in October 2015 has thrown new light on it all. On the island of Islay south of here stone tools have been found which are dated with high confidence 12,000 years old, a good 2,000 years earlier than the earliest previously found evidence of humans in Scotland, in the middle of the Younger Dryas. Whether the people who used those tools were coming north at the time, or were here before and stayed on through the cold is not known. Either way, this discovery confirms it was possible for a variety of life to continue in the west throughout the Younger Dryas.

Take a look at another photo from Amhuinnsuidhe garden. This was taken in the last week of July in the middle of what we are told is the coldest, wettest, greyest summer in 199 years ~


The redcurrants and blackcurrants are about three weeks late, but are here in abundance. Before long we will see rowan berries, blackberries, hawthorn berries. I see many little hawthorn seedlings growing out of last year’s seeds. The roses are blooming. The camellia, rhododendrons and hydrangeas are spectacular.

In the Younger Dryas, summers in the outer Isle may have been not much colder than this one, and with more sun. It may have been drier, and kinder in another way ~ less wind. The outer Hebrides are among the windiest places in the world, and wind is a severe limiting factor on plant growth. Plants consume so much energy just regulating their temperature, and the wind comes usually laden with salt. As long as the Younger Dryas winters were not fatally cold, as long as there was sun in the summers, when the sun is up in June and July here almost twenty hours a day, as long as it did not get too dry, forests had the ability to store plenty of water in their soil, and in a cooler, drier, calmer climate the forest could have adapted and survived. Pines don’t like it too wet.

In time the climate warmed again. The ice sheet on the mainland melted away, and the pines in that forest could cast their seeds ~ even entire cones ~ into a storm wind out of the west, across 80 km. of ocean, to grow and spread across the once again vacant northwest Highlands, and south.

And on the great Western Isle, life went on. Whatever else you believe about all this, common sense must tell us that from whatever source the pine seeds came, some of them landed here.

The abrupt end of the last ice age some 11,700 years ago left Scotland bare of everything except reindeer moss. Birch and then hazel were the first trees to colonise. A trace of pine is first detected in north-west Scotland from stomatal guard cells, at about 10,500 years ago: then two needles occur in Deeside radio-carbon dated to about 10,000 years ago: shortly afterwards pine is found in the Galloway hills, the Solway lowlands and around Moffat, but that did not persist for long. This is the only significant natural occurrence in the Lowlands apart from a brief incursion of pines around Stirling around 4,000 years ago.

The first lasting large scale establishment of pine came in north-west Scotland, notably around Loch Maree, about 9,600 years ago, the trees apparently coming from refugia in Ireland or perhaps from somewhere to the west now under the sea. The north-western pines remain genetically distinct from all others in Scotland. At East Affric and in the Cairngorms, about 8,500-8,400 years ago a similar invasion came from a different but unknown source. Pine spread south into Rannoch about 8,000 years ago and north into Sutherland about 7,600 years ago.”

~ Scottish Forestry Trust, “The history and the myth of Scots pine”, Christopher Smout


Every summer here the hills change colour from the brown of winter to a vivid glowing green. When the forest went, a lot of soil went with it, and a lot of mineral nutrient was washed away, but the idea that the land is terminally barren now is incorrect. A lot of land has the appearance of a thin moth-eaten carpet of turf with bare rock like the bones of the land sticking through it. In some places that is just what it is, but in a lot more the turf sits on a great jumble of rocks, gravel and silt several metres thick.

In places near here, peat moorland has been returned to forest, with the help of gorse. There is an Irish saying ~ “Under gorse there’s gold”. It means where gorse has been growing a while you will find fertile soil. Gorse like clover and alder takes nitrogen out of the air and transports it into its roots, where in time the nitrogen will be released into the ground. It mulches the ground with a carpet of dead needles, looks and smells wonderful in late winter and early spring when not much else does, its brilliant yellow flowers providing energy early in the year for bees, and every year grows up and out from its tips, letting the needles on the branches underneath die, so in time a patch of gorse will grow taller and more leggy. Under its canopy is a sheltered fertile little world where birds can nest, rowan and other berry seeds get dropped and sprout, and an occasional birch or alder seed might tumble out of the sky into an ideal tree nursery. Many times I have found young rowan growing inside gorse. Once I found a shapely hazel tree over 150 cm (5 feet) tall. Then you might see young trees crowning above the gorse ~ given time those trees will spread their canopies over the gorse, which in the shade will grow bluish, thin and wispy, and slowly fade away, leaving a healthy woodland with roots reaching deep into the ground where mineral nutrients have soaked down to form what is commonly known as iron pan.

The conventional method of land management has been to exterminate gorse.

In the outer Hebrides we have an abundant supply of fertilisers, such as the white sand on our famous beaches. Over 70% of the sand at Hushinish is crushed marine organism shells, calcium carbonate with some magnesium carbonate thrown in. It does not dissolve in salt water, obviously, but does dissolve in fresh water. People here have long used it on the land to balance the acidity of the peat and nutrify the soil. It is assisted by seaweed, of which the sea casts up plenty, rich in potassium and other minerals and apparently possessing further life-giving properties. These are traditional ways of adding fertility to peaty ground. I believe these days we may have another.

No one here is currently employed in cutting, polishing and shaping the rock, the gneiss and granite, although the technology exists these days to do it and beautiful results can be achieved with its variety of veins, crystallate intrusions, red and green tints, its wrinkles and folds from the last time it melted and cooled deep underground either side of 2 billion years ago. Instead it is drilled, blasted and crushed to make aggregate for roadfill and standings for buildings. Over 90% of the marble on Skye is treated this way to produce decorative gravel for paths. In the course of this work a lot of dust is produced. Indeed at the quarry outside Stornoway the crushing of gneiss blasted in 20,000 ton batches intentionally produces dust used as filler in concrete and asphalt. One accidental result is a strip of bright green alongside recently made roads on the island where water passes through roadfill and carries some of the minerals present in the rock into the neighbouring ground. In its solid condition the rock is hard, fine grained, rich in metals, tough, very slow to erode. As dust it could have potential as a slow release fertilising agent.

The rabbits and rats, like it or not, are here to stay. At present there is no land predator on Harris and Lewis, apart from otters, who hunt best in the water, and some feral domestic cats.

In Gravir in the east coast of Lewis lives a man who says he used to see wildcat here, around 60 years ago. The wildcat on the Scottish mainland has been on the edge of extinction for years. This island could be an ideal haven for them. I have heard they might kill ground nesting birds on our moorlands. I have good news. There are people ready to work as volunteers in creating wildcat havens. They will set traps, catch and neuter or relocate feral domestic cats, and feral cats are more threat to ground nesting birds than wildcats would be. Wildcats rarely bother to eat birds. Examination of faecal remains left by wildcats confirms that. They mostly eat rats and rabbits. Feral domestic cats, as well as preying on birds, kill slow worms. A managed program to bring wildcat here could improve the chances of the wildlife here already.

A current attempt to exterminate rats in the Scilly isles south of Britain, and a project led by SNH to eradicate black rats in the Shiant isles off Harris, are taking place precisely because of the threat of rats to bird life.

Wildcats would not exterminate our rats or rabbits. Hunters do not kill off their prey. They might make an impact on our rat and rabbit population explosion. A few decades ago, there was a mink farm on Lewis. The mink got out, and soon were thousands. Mink were happy to eat birds including people’s chickens ~ mink like rats can get through tiny holes ~ and may have finished off the ptarmigan, but their fatal crime might have been a habit of going into the rivers to scuff up the gravel beds, setting loose salmon eggs which would drift up for the mink to scoop up and munch down. SNH with the estate owners set about eradicating mink from the outer Hebrides ~ some had smuggled themselves to the Uists, perhaps on big car ferries ~ and last year announced the mink is extinct in the outer Hebrides. The local people are not fans of mink, but no local man or woman I know doubts that the rat and rabbit boom is a direct result of the removal of the mink, apart from SNH, who repeatedly assert there is no connection, and have no plan to do anything about the rats or rabbits.

Somewhere in the Museum of Scotland in Edinburgh there may be a box, and in it may be a wildcat rib bone from this island, from around 1,500 years ago. That would constitute material evidence the wildcat was here in the past. Again, the more relevant issue is the impact of the wildcat’s presence here now and in the future. And who should decide. I would not be advocating the return of the wildcat, however much I want it here, were it not that almost all the local people I’ve spoken to about it agree with the idea.

North Harris is now a community owned estate, and will never be sold again. A higher proportion of this island is now community owned than anywhere else in Scotland. But over 90% of North Harris is off limits to any activity without the consent of SNH. It is designated the North Harris SSSI, site of special scientific interest, preserved as bare rocky acidic peat moorland. A Citation accessible on the Scottish government website explains what is so special about it. It talks of the scarcity of species, black lochans, mosses. It does not speak of the dominant species of the SSSI, the subsidised sheep, deer and deer hunters.

Hushinish bay on the west coast of Harris deserves its place in the minds of many people lucky enough to visit on a fine day as one of the most beautiful beaches in the world, especially if someone has been out recently removing the plastic garbage. A sign advises visitors to admire and respect the machair, an environment unique to the coasts of the Hebrides. I have seen a photograph of that machair twenty years ago, and people tell me of the colours, the fragrance, the bees. It was beautiful. It is not the same now. A woman who has lived alongside the beach for 90 years believes the proliferation of rabbits is the cause. It is riddled with burrows. An absurd number hop about perfectly blasé about the state of the world. We eat a few ~ the locals used to, but won’t now since they saw some with mixamatosis about twenty years ago. Mixamatosis came to the island about fifty years ago, maybe on wheels of cars from the mainland heading for the Ullapool ferry on roads smeared with dead sick rabbits. Someone had introduced it to the Highlands in an attempt to control rabbit numbers after predators like wildcats had been shot, poisoned and trapped at the behest of the estates. Wildcats would not eat all the rabbits at Hushinish. They might modify the rabbits’ behaviour.

There were no hedgehogs in the outer Hebrides fifty years ago. It is said four were introduced in 1974 by someone on South Uist with too many slugs in his garden, and now an estimated 5,000 inhabit the Uists and large areas of Harris and Lewis. It is quite a conquest by a little animal in severe decline on Britain’s mainland, to have spread north about 60 km through the Uists, hopped on the ferry to Harris, spread through Harris, over the hills and down into much of Lewis ~ starting from four forty years ago, we’re told. Without hedgehogs and frogs we can only wonder how many slugs would be here. There are still plenty of slugs for slow worms, and cuckoos, who also eat slugs, and are still heard here every year.

Supporters of the way things are point to the hedgehogs as a warning against rewilding, which means bringing back animals where they once lived and are now locally extinct. The hedgehogs, we are told, threaten the existence of our ground nesting birds, whose eggs they eat. A recent article by the chief executive of the Scottish Crofting Federation makes this argument, and goes on to state that the attempt to remove them undertaken by SNH has been costing “about £800 per hedgehog”.

Crofting has given me opportunities I would have never had otherwise, and I believe in the future of crofting. I don’t want to fall out with the CEO of the SCF. Still, I see flaws in his argument. The hedgehog’s arrival was not a rewilding initiative. No rewilding advocate would have proposed it, with no evidence they were ever here in the past. Whoever brought them was concerned with flower beds or vegetable crops, not the wider environment. And £800 per hedgehog sounds to me like a generous wage to remove about one a week.

These days many crofters keeping livestock buy in feed and hay from the mainland. I know a crofter who has found a hedgehog in a bail of hay. That one was dead. In his opinion another might have survived. I would not be surprised to learn as well that another gardener or two has imported some.

The impact of hedgehogs on bird life is now questioned, as the CEO’s article acknowledges. In Hushinish bay twenty years ago there was a thriving population of sea birds, I’m told. I’ve never seen that. There are very few now. There are no hedgehogs out here. Some say the introduction of white tailed sea eagles on the nearby small island of Scarp is responsible. Some blame the rats. In the same time a local population of seals has disappeared, and it is hard to see how the eagles or rats can be blamed for that. It could be the proliferation of camper vans, but I don’t see much possibility of anyone trying to eradicate them.

We read of a plan to spend £7 million on another eradication attempt on the hedgehogs, while local public services are being cut by about the same amount, and we wonder at the sense of it all. I would need to know more before passing judgement on the hedgehogs here, or whether we can get rid of them anyway. Apparently we would only have to miss four … meanwhile another recent arrival, the New Zealand flatworm, is munching its way through the island’s earthworms. I don’t know if hedgehogs eat them. I do know on mainland Britain the carnivorous Iberian slug has arrived, growing to 30cm. long, and hedgehogs eat them. It would be a shame to exterminate the hedgehogs then want them back next year. Maybe we need something to eat a few hedgehogs …

The days when anyone here could seriously claim to be protecting a pristine island environment are gone. Change has come and more is coming, faster and more changeable than it has in at least 8,000 years.We have imposed the change, and one way or another we will help life to respond. Fact of life.

It is estimated the world’s peat beds since the Ice Age have absorbed close to 600 gigatons of carbon, about the same as the Industrial Age has emitted. You may like the idea of preserving our moors just as they are, but in reality in a changing climate that is not an option. The northern peat moors might soon be releasing carbon back into the atmosphere. Once they were forests. Most of that land can be again. I need a better reason why not than the desire of a few people for a free field of fire, to preserve a stressed out urban population’s myth of a pristine wilderness of wide open spaces, or to entertain coach parties with many miles of bonnie purple heather.

The full story of the deep past in the outer Hebrides is something we will never know. Something that could cast new light on our past may be waiting deep in Barabhas moor in the centre of Lewis, where the peat reaches 9 metres deep, or in a box in Edinburgh, or in slow worm DNA, or under the sea, or somewhere I can’t imagine.

The picture I see in the deep past of the outer Hebrides is more varied and colourful than the conventional account. There is a downside to it. The conventional account encourages us to believe natural forces, above all natural shifts of climate, stripped the trees from the land to create the landscape we see. I don’t believe it. Climate variations came and went but a healthy diverse forest can respond and survive. We killed it, humans and our domestic animals, our appetites and our wars, as sure as the Icelanders killed their birch forest. These islands are beautiful after all we have done. In all their beauty, these islands are a holocaust site scarred by our cruelty, and when the storms blow in over our naked land, we know it.

The people who lived here as tenants of landlords not long ago could do nothing to change it. Improve your home and you were likely to be rewarded with a rent increase. Make it too desirable and you might get booted out. You could grow some vegetables, hope wind or rabbits did not ruin your crop, keep some sheep, a cow or two .. they made a beauty out of their lives, lovely tweeds from their wool, and found a strength in themselves, durable houses they built out of skill and hard rock, and an ability to live between the naked land and the wind and the sea a life of hard work and music and charm.

We can change it. Every year here I see a growing presence of millions of young trees. Most were planted in community woodland projects, gardens, croft shelter belts. Some are springing up now on roadsides flanked by fences to keep away sheep. Some are survivors of a past era ~ a rowan clinging to a crag, a juniper crawling across bare rock, willow waiting to rise out of relentlessly nibbled grass. We can change it. We can let this land instead of the Calmac ferry feed us, create opportunities for our young people rather than the tourists ~ the local people, naturally courteous and friendly, still unconditioned to being professionally friendly, call them visitors. I think our visitors might find more attraction in islands committed to regeneration, youth, diversity and exploration than a Hebridean preservation theme park.

The reality of the deep past in the outer Hebrides reflects the requirement of the future ~ diversity, resilience, balance, adaptability, an ability to welcome nature’s gifts and nature’s power. It is up to us to find our happiness, health and a sustainable future inside the subtle beauty of its interactions, changes and mysteries, not on top. What I mean by that would take another essay. I want to write it in the land.


Rabbit numbers in Ness have reached ‘epidemic levels’ says a crofter from the district who warns something has to be done to protect livelihoods and the machairs in Ness.

Kenny Macleod claims numbers have escalated to levels previously unseen in Ness and residents have to take action before it’s too late.

He said: “There are tens of thousands all over the whole of Ness and it’s got so bad that people can’t even plant anything. They are not just on the machairs and moors either as they are on the crofts and around the houses.

“Every croft is the same and there are so many more than I’ve ever seen. It has escalated out of control. They have tried culling their numbers in the past with people taken up for a week or two but it costs so much and they don’t seem to be denting the numbers.

“There are holes everywhere with the old football pitch a good example. Until eight or ten years ago we could use it all through the winter but now it’s unusable. Even the current pitch has rabbits on it every day and in a match, of course, we had that incident which stopped play.”

It was during a recent Ness senior match that a rabbit hole opened up inside the six-yard box during a match, forcing team substitute Donald Macsween to fill it with a spade to prevent players tripping and being injured.Kenny says Ness could take a look at the Island of Canna which was the scene of one of UK’s biggest rabbit culls, following a population explosion last year.

He continued: “Urras have been trying to look at options but the problem is the cost.

“I’ve been trying to find out how the Island of Canna funded their own cull where they culled 9000. In Canna I believe they were selling all the rabbits they culled to France for £1 a go, so that’s something we could consider trying. It’s been getting worse and worse each year and there are a lot of black rabbits in Ness too which is a sign it has reached epidemic levels. The next step has to be to try and take this forward with a meeting of everyone affected around the table. Everyone realises the problem but the cost is the stumbling block.”

A spokesperson for the National Trust for Scotland (NTS), who own the Island of Canna, said the cull was carried out for conservation reasons, with concerns reported by residents expressed that the rabbits were digging up Canna’s important habitats and environmental sites and there was even concern that they were disturbing archaeological remains.

The trust continued: “We undertook rabbit population control on Canna in early 2014, after it was estimated that the population had reached 16,000. There were concerns about the environmental damage caused, including suggestions that burrows had contributed to a landslide in Autumn, 2013.” Discussion on the issue continues in earnest.

Stornoway Gazette, 20th August, 2015

Eroding the mountains of inertia | Land Matters

~ this is a link to a recent article and passionate subsequent discussion initiated by the Loch Garry Tree Group, founded over 40 years ago by Ron Greer. The group has begun a transformation of a formerly bare highland glen, 500 metres above sea level, near the A9 road north of Perth.

Conventional wisdom assured Ron trees would not survive there when he began planting young trees he was cultivating in his own garden, at his own expense, protecting them from sheep, deer and rabbits by fences he built himself. I joined the group for the autumn planting about twenty years ago, and saw rowan trees red with berries and birch leaves golden, bursting to get out of their fenced containment.

Ron Greer can be called one of the fathers of what is now the Reforesting Scotland movement. The trees thrive, although the landowner has prohibited the planting of gorse … the reality of what is happening in Glen Garry and what it can mean for the rest of the Highlands and Islands is proving slower to take root in the urban power centres which control the land and the law.

Anyway, Ron Greer changed my life.


Ron Greer

A Paper by Steve Webster, Isle of Harris



  • Sean Byrd6th, April 2018 @ 0:25

    This article about the past and future of the Outer Hebrides was really and truly nothing short of sublime. Your approach to things is the exact holistic approach that I crave and admire. I am going to school at Bangor in Wales, and wish to get involved in both the preservation of vernacular subsistence culture in the Norse-Gael region, crofting, rewilding, and reforestation, and you sound like the exact type of person who I would hang out with, like, all the damn time. I hope things are going so well for you, and that hopefully I can work with you one day, as what you are doing is pretty much identical to my wildest fantasies.

    You might be my hero,


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