I thought you might be interested to know that I have just finished the report of the main findings from my Churchill Fellowship, and it is now available to download from the Winston Churchill Memorial Trust website, or follow the link here
Since returning to Scotland in July, I have been sharing the findings from my Fellowship widely in the hope of trying to stimulate a conversation about “re-flowering” the woods of Scotland.
A recent exchange with Neil Mackenzie, a well-known and well-respected Scottish woodland ecologist, resulted in him sharing a photo with me of a wood on a tiny island off the west coast of Scotland that he had visited the previous year:
As you can see from the picture above, the woodland is carpeted with flowers, just like the woods in Iceland. It would seem that although the wood could be reached by herbivores, the local people make strenuous efforts to keep them off, and so, although unfenced , this wood is essentially free of herbivores, and by the look of the hazel trees, has been like this for quite some time.
I will certainly be checking this wood out for myself next spring, but learning of the existence of this wood has been really great, and I would be interested to hear of any other similar flower-ful un-grazed woods out there that you might know of!
Welcome to my Blog!
The picture above was taken in a very beautiful birchwood I visited in Iceland this summer where there have been no large herbivores grazing for over 100 years. In the following pages of this Blog you can read about my travels this summer with the help of a Churchill Fellowship to visit woods in different parts of Europe where there are few or no large herbivores.
As most woods in Scotland have high numbers of deer and sheep in them currently, and have done so for hundreds of years now, I wanted to find out what woods with no (or very low) browsing pressure looked like. In particular I wanted to know whether they have more flowers than our Scottish woods – which generally have very few flowering plants in them, and few of these ever get to flower and fruit!
As you can see from the picture above, this Icelandic wood is literally stuffed full of flowers. Most of the woods I saw in Iceland looked like this and they all had more flowering plants than grasses, and most of these plants were flowering. It was the same story in most of the Norwegian woods that I visited. In the Isle of Wight, as the woods tended to be of the type that cast a heavy shade, there were not so many flowers but an unbelievable diversity and abundance of ferns and climbing plants.
So I learned that it didn’t really seem to make much difference what kind of woodland – whether a northern birch woodland or a Pyrenean silver fir woodland – if there are no herbivore impacts they all have a productive understorey with a great many flowering plants or ferns, and many, many beautiful flowers which support not only a wide range of insects, small mammals and birds, but also still in some places a thriving local micro-industry of forest jam and honey production. So they are all quite different from Scottish woods which have mostly been grazed for the past several hundred years and completely lack a productive understorey.
I hope that you enjoy reading about the woods I visited as they were truly inspiring. I hope that like me, these few observations might make you wonder where have all the flowers gone from our Scottish woods, and how much more beautiful and biodiverse they might be if they had just a few less munching mouths in them….
The photo above is a picture of the woodland where this project started back in 2012. This little bit of woodland is in a deer fenced exclosure on the Isle of Mull set up by Peter Wormall back in the 1980s. It had remained deer and sheep-proof all that time. In all the 30 years I have been a woodland advisor with Scottish Natural Heritage, I had rarely seen a woodland like this. This small wood was like a little bit of paradise. Here there was an understorey and a profusion of flowers. The sound of birds and insects filled the air.
All of a sudden I realised something is missing from most Scottish woods… Several hundred years of deer and sheep browsing has left our woods without their “filling” – there is the canopy and the ground, but everything in between these layers has been eaten out.
Our woods are like the “sandwich without the filling” –“the burger with only the bun”!
As woodland managers and advisors we have for so long been so focussed on getting tree regeneration that we have seem to have failed to notice that woods are actually much more than just the trees. Even if the trees regenerate, without all the other climbing and trailing plants, shrubs fruit bushes and tall herbs they will never be “woodland”; just a load of trees. Without the brambles, raspberries, blaeberries, ivy and honeysuckle flowers there is no food for the insects; no food for the small mammals, no food for the birds and nowhere for them all to make their homes.
Woods that have been eaten from the inside out cannot offer the full range of habitat niches and biodiversity potential, and having such low productivity provide little in the way of potential livelihoods to local communities.
I already knew that in other countries there were woods and forests with much lower herbivore impacts than in Scotland. I thought it could be an interesting project to visit woods in other parts of Europe where the climate and geology is comparable to Scotland, but where herbivore impacts are much lower, and to collect evidence of how that space under the forest canopy is different, and what this difference means for the flowering plants and all that depends on them.
Last year I returned to the exclosure on Mull to discover that the fence has been taken down, for it was considered that “enough” trees had regenerated and that it was time to restore grazing to the woodland. In the space of less than 2 years, much of that ecological richness that had taken over 30 years to develop had been completely wiped out. Apart from a few sapling trees, you would never know what abundance of flowering plants this wood had come to support for they had all been eaten or trampled into oblivion. The photo below shows the same spot, same time of year – all the flowers have gone!
This was the moment when I knew I had to try and do something to switch the focus of our efforts onto ecosystem restoration and away from tree regeneration, for until we can bring herbivore numbers down to a sustainable level we will only ever have woodland sandwiches without the filling!
Vaglaskógur is a 300-hectare forest in Fnjóskadalur, north Iceland, and the second largest forest area in the country. This forest has well organized camp sites and recreational areas and is very popular with visitors.
Vaglaskógur lies within a forest conservation fence which protects an area of about 690 hectares. Conservation of the forest dates back to 1905 – and no other birch forest in Iceland has been the subject of strategic conservation as long as Vaglaskógur. The birch trees in Vaglaskógur have a distinctive character. The trunk is notably light in colour and they grow straighter and taller than most other birches in Iceland. The Vaglir birch can reach well over 10 metres and the highest birch presently in the forest is about 14 metres tall. One of the most important tree nurseries in Iceland is located at Vaglaskógur, and timber felled from the forest is used for fence poles, fire wood and furniture.
We visited Vaglaskógur on Bjarni’s advice as it is another birch woodland that has been protected from grazing for nearly 100 years. As well as the beautiful birch trees the forest had a good number of mature rowan trees (see above) – full of flowers and literally alive with insects.
Although there seemed to be more conifers planted among the birch in this wood, and also more lupins present, overall, the flowering plants in the field layer in this wood were the most impressive of all the woods we had seen on Iceland for their sheer profusion. I have never seen a woodland floor with quite as many flowers!
The usual wood cranesbill and buttercup were abundant, but there was also masses of flowering small cow-wheat – an extremely rare plant in Iceland and according to Flowering Plants and Ferns of Iceland not previously recorded from this region. But here it was present in vast drifts of bright yellow flowers – I’ve never seen cow-wheat growing like this in such a profusion of flowers, mixed in with wood cranesbill. So very beautiful – and also appreciated by a great many bumble bees and other insects.
Frog orchids, moonwort, common wintergreen, yarrow, stone bramble, lady’s bedstraw, autumn hawkbit, alpine bartsia and northern butterfly orchid were flowering in profusion all over the wood.
In the warm evening sunshine it was an absolute joy to experience and I hope you can get a sense of the sheer flowering exuberance from the photos. The floor of the forest was quite literally carpeted with flowers! The woods of Iceland that we had visited had all had more flowers than I have ever seen in Scottish woods, but the flowers of Vaglaskógur were almost literally “out of this world”!
Aspen is pretty rare in Iceland with only 6 known sites in the whole island. Not surprising really, as it is so palatable to grazing animals it is amazing that any has survived at all to recolonise the expanding birchwoods. Thor Thorfinnsson at the Icelandic Forest Service office in Hallormsstaður had mentioned to us that there were some stands of aspen nearby in the birchwoods by Egilsstaðir, and so despite the ominous black clouds threatening very heavy rain we just couldn’t resist the temptation, so set off to try and find these elusive and very rare trees.
From a high vantage point within the forest (photo above) we scanned the woodland canopy and before long spotted the characteristic trembling leaves of the aspen catching the sunlight as they shimmered in the evening breeze:
The trees that we saw in the wood on the edge of the small town of Egilsstaðir did not appear to be very old trees – none of the trees we found were taller than 10 metres, but it was hard to know just how old they might be:
One thing about this stand of aspen that was amazing to see, was the extent of the suckering in the absence of grazing – there was literally an aspen forest in the making! I hope you can make out the dozens of young aspen trees bursting out of the ground in the photo below:
The ground flora of this wood was just as rich, and in addition to the usual suspects this wood also boasted some juniper – this was the first time we had found juniper in a woodland. All in all a pretty special place!
I couldn’t help wondering whether with the recent decline in grazing in Iceland this tree is now recovering from a position of having a very minimal presence on the island either through holding on as rootstock suppressed within the ground for many years when grazing pressure was much higher, or whether these are newly arrived trees in Iceland or whether they have expanded out from refugia that survived somehow in inaccessible cliffs or ravines…? It could certainly make an interesting subject to investigate, with potentially useful insights for the restoration of aspen in Scotland where this tree is also currently suppressed by herbivores.
Not far from Egilsstaðir we visited an organic farm called Vallanes. This beautiful area is known for its forests and relatively mild climate, and the fields around Vallanes have been shaped by the planting of over 1,000,000 trees in a system of agro-forestry with willow shelterbelts that protect the growing crops.
A surprising range of crops are grown on the farm including barley, lettuce, kale and herbs, but of particular interest to me was the Aspen House – the newly finished shop and cafe which has been built entirely out of aspen that was planted on the Vallanes farm 40 years ago. It is apparently the first wooden building on Iceland to have been constructed entirely from timber grown on the island.
Now that’s what I call impressive for a country which not so many years ago was struggling with chronic overgrazing, woodland loss and soil erosion! It just goes to show what can be achieved with vision and determination. An inspiration for Scotland!
Hallormsstaður Forest in the eastern part of Iceland is part of the National Forest estate which is managed by the Icelandic Forest Service. The birchwood remnants at Hallormsstaður farm were first protected with a ring fence in 1905 in a quite visionary action for the time, becoming Iceland’s first national forest. Prior to that, traditional agriculture had been practised at Hallormsstaður, and there were just scattered, crooked birch trees around the farm – there was nothing in the way of a forest here. The photo below shows the farm in 1950, by which time the birch scrub was already starting to spread up the hillside:
The birch forest at Hallormsstaður now extends to about 350ha that has grown up within the original fenced area:
The growing conditions for trees at Hallormsstaður are amongst the best in Iceland, and the tallest birch trees here reach about 13 metres, whilst the oldest trees in the wood are believed to be 150-160 years old.
There is more rowan in this forest than anywhere else in Iceland (along with plenty of regenerating sapling rowan trees due to the lack of any browsing pressure!) and here they can reach a surprising 11.7 metres tall. The table below shows average heights attained by the different tree species that are growing at Hallormsstaður:
The understorey also contains frequent woolly willow, pictured below amongst northern bilberry which was very abundant throughout this forest:
Situated in the east of Iceland, Hallormsstaður has a slightly more continental climate than the rest of Iceland, and this is reflected in the vegetation to some extent with species such as chickweed wintergreen (which is only found in the extreme east of Iceland) common in the wood. Another plant with an eastern distribution on Iceland which was common in the forest was the Scottish bluebell!
The ground flora in Hallormsstaður was not as rich in flowering plants as the other birchwoods we had seen in Iceland up until this point, but there was well developed structural diversity and plenty of berry bearing bushes including stone bramble and northern bilberry, and both raspberries and redcurrants can also be gathered in the forest:
Thus the forest and its understorey provides a wealth of food, nest sites and protection from predators for many species. Year round residents include redpoll, wren, goldcrest, ptarmigan and raven, and summer visitors include redwings, snipes and meadow pipits along with woodcocks and wagtails.
We saw lots of fungi in Hallormsstaður, and edible mushrooms recorded from the wood include larch bolete, birch bolete, birch polypore (a bracket fungus) and slippery jack.
In a pamphlet published by the Icelandic Forest Service in 2013 that was given to me by Thor Thorfinnsson the forester at Hallormsstaður there is a quote:
“Among the first things that visitors to Iceland usually notice are that it is not as warm as where they came from and there is a lack of forests in the landscape. Logically, they connect these two facts and come to the conclusion that Iceland is too cold for forests. This impression is often reinforced when they see the “forests” of low-growing and crooked native birch. However, it is past land-use and not climate that explains the tree-less landscape. In fact forests grow as well in Iceland as they do in parts of the world where forestry is a major industry.”
Currently just over 1% of the area of Iceland is native birch forest. Obviously some of this is will be low scrubby newly establishing woodland, but from what I saw there is no doubt that Iceland is capable of supporting structurally well developed and species rich birch woodland when the pressure from grazing is removed. The birch forest of Hallormsstaður really felt like it could have been in Scotland – sad to say though that it is a long time since I have seen a birch wood in Scotland that compares to any that I have so far seen in Iceland.
Beneath the imposing skyline of volcanos and glaciers, birch woodland is spreading over the south facing slopes of Öræfajökull. This area around Skaftafell in the south of Iceland has a mild, pleasant climate, benefiting from the towering shelter from the north of Öræfajökull, and possibly as a result, the birch trees in Bæjarstaðarskógur grow higher than most other native birch in Iceland. In fact the birch from this part of Iceland looks more like silver birch (which does not grow on the island), and is the seed source for the urban birch planted in Reykjavik! The bark of the downy birch tree in the photo below does indeed resemble silver birch more than the downy birch found commonly in Scotland. Biologists studying the pollen of Icelandic birch trees have now discovered that the downy birch in Iceland is in fact a product of hybridisation with dwarf birch (Betula nana) from southern Europe! So, all is indeed not quite what it appears to be…..
We were visiting Bæjarstaðarskógur today in the company of Dr. Bjarni D. Sigurdsson, Professor of Forestry at the Icelandic Agricultural University, and as we strode out across the vast expanse of volcanic shingle that we needed to cross to get to the forest, Bjarni told us that the forest of Bæjarstaðarskógur has been in his family’s farm since the 1400s! Bjarni has known the forest since he was a child – so there was no-one more suited to show us around this incredibly beautiful and interesting ancient woodland!
Bjarni said that since the sheep grazing and wood cutting ceased at Skaftafell in 1985, the vegetation has undergone great changes, with woodland rapidly colonising the glacial deposits in front of Skaftafellsjökull and in Morsárdalur valley. Since 1990 the area of native woodland at Skaftafell has increased by a whopping 9%! The treeline has migrated upwards from 350m asl in 1960/70 to 590m asl today, which is partly due to the reduced grazing, but also because of the changing climate (there has been 1.5 °C warming since 1990). During this time growth rates have also increased. Flowering plants such as garden angelica, wild angelica, sea pea and arctic river beauty are taking root in the skeletal soils (see photo below):
The birch trees that are colonising the shingle in the picture above all date from 1981/82 when an extreme wind from the north-east carried the seed from the woodland on the hill in the distance across the shingle of the glacial morraine for up to 30 kilometers!! Icelandic biologists studying this colonisation event have discovered that for the first 20-30 years following germination, the newly established birch seedlings seem to focus their efforts on developing strong root systems, and above ground it appeared as if the plants had gone into “check”. But once the root systems had established, then the young trees started to grow, at which point they made very rapid progress despite the poor soils. The trees in the photo below have grown from 1m height in 1985 i.e. in 30 years they have grown to a height of 6-8 meters!! Who says trees can’t grow on Iceland?!
Within this newly establishing stand of birch trees we came across an interesting mushroom – Black helvella:
There are over 100 species of edible mushroom in Iceland. Bjarni has recently completed a popular guide to mushroom foraging in Iceland, and run a few workshops to try and encourage people to go out into the countryside and use the wild food that they find there. There is no traditional culture of mushroom foraging in Iceland – being predominantly Protestant, and in common with other Protestant countries in Europe mushroom foraging was linked to witchcraft, and therefore has historically not been actively practiced. With the influx of eastern Europeans into Iceland more recently, there has been a surge of interest in foraging for mushrooms in the woods, with the new generation of trendy restaurants in Reykjavik a ready market for the produce!
Alongside the native flora, lupins have also begun to colonise the glacial deposits in front of Öræfajökull and Bjarni explained a little known fact which is that the Alaskan lupins normally only live for 30 years, and are self-limiting by two moss species that colonise the ground under the lupin “canopy” creating a thick carpet on the ground. The lupin seeds are unable to get established in this moss carpet and so the lupin dies out, grass colonises and in time takes over dominance from the lupin. In the meantime sheep grazing can help limit further spread, as sheep will eat and remove the new seedling plants. They will also take a limited amount of forage from the mature plants, but as these contain neurotoxins they need to have access to other browse otherwise they can become ill.
It is known that the woodland at Bæjarstaðarskógur was heavily utilised until about 1830, with all the big trees in the forest having been felled by that time. The then owners of the forest lived 60km away from the wood, and it was becoming less and less economic to extract wood from the forest. So, when coal started to be imported from the UK, wood cutting ceased altogether in 1850. In 1910 a botanist visiting Bæjarstaðarskógur wood described it as the most lush forest in Iceland. The oldest trees there are now believed to be 150-180 years old, so it is unique in Iceland as it is the only place where there are very old trees and any quantity of deadwood. It is interesting to speculate on what the deadwood invertebrates of this wood might be like, since saproxylic invertebrates are not normally known for their dispersal capabilities… Today the birch trees in Bæjarstaðarskógur reach 10-12 metres in height so they are substantial forest trees by any standards.
Bjarni commented that he was noticing far more fallen trees on this visit than on his previous visit, which he suggested was probably due to the fact that many of the trees are now coming to the end of their natural lives. As there is no browsing pressure at all in this wood, and most of the trees produce basal shoots; when a mature tree falls down it gets replaced by basal shoot re-growth which can be up to 30cm/year! Growth like this from basal shoots on birch is just something you never see on birch in Scotland due to the browsing pressure.
The canopy in Bæjarstaðarskógur wood is predominantly downy birch, but there is also frequent rowan in the canopy as well as in the understorey which is otherwise dominated primarily by tea-leaved and woolly willow:
According to Bjarni, there were only 2 rowan trees in this wood 70 years ago, so all the others are most likely the progeny of these two parents:
The field layer in Bæjarstaðarskógur comprised the now to be expected carpet of flowering plants including wood cranesbill, wood horsetail, sweet vernal grass, meadow buttercup, stone bramble, smooth meadow grass, common valerian, garden angelica, fescue, heath wood rush. All of which were flowering profusely:
The calls of the frequent redwing, redpoll and Icelandic wren alongside the drumming of snipe formed the sound backdrop to a most incredible afternoon in a very special woodland. Before embarking on this fellowship I could never have imagined that un-grazed woods could be this beautiful, this lush, this vibrant and full of life. And to see all this in a wood so far to the north of Scotland was really an unexpected bonus!
Vatnshornsskógur – literally “forest in the corner of the lake” – was declared a protected forest under the Nature Conservation Act in 2009. The region had become popular for summer houses, and there was growing pressure to build summer houses within the forest so the nature reserve was created “to protect the natural, relatively untouched tall birch forest with its luxuriant undergrowth together with the genetic characteristics and diversity of the Icelandic birch”.
Vatnshornsskógur is considered to be the oldest birch woodland in West Iceland, and is extremely dense, with unusually tall birch trees. It is situated in an area that has been managed historically for sheep farming and never been densely populated. Historically the forest was cut for firewood etc, but in the last 100 years there has been no felling at all within the woodland, and with the decline of sheep farming in the region, there has been no sheep grazing in the wood either. Many of the farms in the area have been converted to forestry for the government provide good incentives to encourage tree planting, covering 95% of the costs of planting fencing and roads and providing the trees free of charge.
We were visiting the forest today as guests of Borgþór Magnússon of the Icelandic Institute of Natural History. Borgþór has been carrying out monitoring studies in partnership with the Icelandic Agricultural University since 2004, to see how the vegetation is changing as the forest grows. As part of this work, they are also looking at how the productivity within the woodland differs from the open hillside outside the wood – the results of this work when it is complete will be very interesting to hear.
Almost the entire southern side of the lake is covered with birch forest – much of it recently regenerating but a good chunk of it dates back at least 100 years! The soils here are glacial till up to 1 metre deep on basalt, so in Icelandic terms – pretty good!
Vatnshornsskógur is one of only two locations for the rare lichen Alectoria sarmentosa ssp sarmentosa which was discovered growing in the forest by Borgþór in 2003. Norwegians call this species hair lichen and use it for dying; in Alaska it is used by indigenous people for wound dressing and nappies!! The picture below shows Borgþór amused to read about his discovery on the reserve signpost.
So what was Vatnshornsskógur birch wood like? You may be wondering…..
It was amazing…a forest of twisted and contorted ancient birch trees covered in lichen, and a field layer full of flowers. Despite the claims on the reserve sign, the canopy was NOT actually very high – in places it was barely above our heads! and to walk “through” the wood required quite a bit of ducking and weaving!
Borgþór commented that when he had last visited the wood in 2004 there had been much less understorey, compared to now – it was really quite difficult to get through the wood and in places we literally had to get down on our hands and knees to get through! The canopy of the wood was predominantly birch (and somewhat surprisingly there was no rowan at all in this wood) with an understorey of woolly willow and tea-leaved willow.
The wood was full of the usual Icelandic breeding birds: redwing (see nest below), Icelandic wren, snipe, meadow pipit, redpoll and ptarmigan (which, being the only grouse species resident in Iceland is also a favourite with Icelandic hunters as a traditional speciality for the Christmas dinner table!)
There was plenty of deadwood, as the birch trees, when they reach the end of their lives get blown over, and in the absence of browsing, the basal shoots are able to grow up and in time take the place of the fallen mature tree.
The old trees are encrusted with lichen – normally birch in Scotland doesn’t get that much lichen as it has a fairly acid bark and there are more suitable alternatives such as hazel, aspen and ash.
Just like the other woods we had visited, the floor of Vatnshornsskógur was lush with tall herbs in full bloom such as wood cranesbill, stone bramble, meadow buttercup, water avens, autumn hawkbit, blaeberry and northern bilberry. Above the drumming of the snipe and the calling of the redwings the contented drone of insects visiting the flowers of the forest could be heard.
It was really hard to believe that all of this riot of biodiversity was playing out within a few hundred miles of the Arctic Circle….
Having had our curiosity aroused by what we had seen at Þingvellir, we were curious to explore more of Iceland’s protected birch woods. At Laugarvatn there is an area of birch woodland that has been protected from grazing for over 100 years that is part of a very extensive forest that covers the lower slopes of the hills for many kilometres.
Laugarvatn is a shallow lake, about 2 km2 in size, and is located in the inlands of Árnessýsla, midway between Þingvellir, Gullfoss and Geysir, about 100 km from Reykjavík. Under its floor there are hot springs heating the lake so it is warm and suitable for bathing all year round!!
Laugarvatn was partly planted by conifers in the 1950s and 60s, but we wanted to visit the area that was fenced in 1910. It is known to be one of the very few places in south Iceland that still had wild rowans in the late 19th century according to a reference by Einar Helgason from 1899. Initially, the fenced area was only 3,3ha, but the fence was then extended to 75ha in 1914.
At the time of enclosure there were some scattered birch woodland remnants 1-2 metres tall within the area, but in between it was apparently mainly un-forested grasslands and eroded land. Since 1912, the birch woodland has greatly extended its coverage, starting with the 75ha of protected land but then little by little, as sheep numbers have declined, it has spread to become one of the largest continuous birch woodlands in Iceland extending for over 35km from the foothills of the mountains in Laugarvatn to Geysir (Haukadalur).
Like Þingvellir, the ground flora at Laugarvatn was lush and very diverse – especially compared to that of similar woods in Scotland. The flora of the wooded areas (which tended to be on deeper soils and a bit damper) was a mix of tall herbs such as meadow buttercup, wood horsetail, wood cranesbill, hawkweed, tufted hair grass, meadowsweet, lady’s mantle, dandelion, and water avens (see below, left). Rowan was a frequent associate in Laugarvatn, not only in the canopy; but it was also abundant within the woodland as sapling trees (below, right) – something which is rarely seen in Scottish woods as rowan is normally one of the first to be eaten!
Within one area of woodland we made a very surprising discovery – Herb Paris – normally an associate of ash/elm base-rich woodlands in Britain, uncommon in Scotland and a very rare and unexpected find in Iceland!
According to the Guide to the Flowering Plants of Iceland, Herb Paris has only been recorded from a small number of locations. Its presence at all in Iceland is rather hard to understand. In Scotland this plant has a very restricted distribution, but now having found it in un-grazed woods in Iceland I have started to wonder whether, with lower grazing pressure, it might otherwise be more common in Scottish ash and hazel woods. Another interesting find was common wintergreen (below left) within the birch woodland areas.
In between the wooded areas, the soil was thinner and there were patches of more alpine acidic vegetation which included mountain avens, alpine bearberry, northern butterfly orchid (above right), heath spotted orchid, bladder campion, alpine fleabane and wavy hair grass.
Lupin has spread into the more open areas in the woodland, but it was interesting to see that despite the density of the mature plants, young birch saplings are managing to regenerate through the lupins:
Lupins do not tolerate shade, and so eventually, once the birch starts to close canopy, the lupins will be shaded out. The woodland areas in Laugarvatan had no lupin within the field layer, it was only present in the clearings.
The birch trees at Laugarvatn appear to be growing very slowly – we found a cut stem of a birch tree with a diameter of about 5cm that was 40 years old! The tree that it was growing out of was clearly much older…so some of the trees at Laugarvatn clearly are old indeed!
We noticed that some of the birch leaves were showing signs of moth damage (see photo below). We heard from a number of the folk we met in Iceland that unfortunately increasingly birch are being affected by novel pests and pathogens. Whilst these are not (so far) actually killing the trees, they are causing damage and reducing annual growth, and in a country like Iceland where growth rates are anyway very slow this could be significant.
On the “flip side”, the climate in Iceland over the past decade appears to have been warming. The winters are shorter and less severe; summer temperatures are on average warmer, and many people commented to us that this has definitely had a noticeable impact on tree growth rates, which, in turn is resulting in more rapid expansion of birch woodland in Iceland.