The beautiful birch
Credit John MacPherson
By Peter Lowe, Senior Outreach Adviser for Woodland Trust Scotland
Birch is a much under-appreciated tree, but it’s very important in Scotland’s rainforest. Across the whole rainforest zone, it’s actually the most common tree you’re likely to come across.
It’s particularly prominent in the rainforest woods of northwest Scotland, where you should see it growing with willow species, hazel and aspen. Sadly, these woods have endured heavy grazing by deer and sheep over the last couple of centuries, which has eliminated most of the more palatable aspen, hazel and willows, except those survivors that cling to cliffs. That means over large areas, you’ll find almost pure birchwood, in sharp contrast to the rainforest woodlands further south in Argyll and Lochaber, which are dominated by oak, ash and hazel.
Having an acidic bark, the lichen species found on birch trees are more limited than on hazel, rowan and oak, but they can nevertheless be varied and are still ecologically important.
In spite of the misconception that it doesn’t live long, birch is often a component of upland wood pastures that have existed for hundreds of years, and was frequently modified by pollarding and coppicing to harvest wood. This process can also extend its lifespan.
Credit Phil Formby
Birchwoods and their importance for cotton spinning
The swathes of birchwood that once covered the Highlands are much reduced today, due to grazing and the industrial revolution; however, they have a very specific link to one industry in particular: cotton spinning.
When cotton is spun, it’s wound onto bobbins, and 200 years ago, those bobbins were made of birch, and turned in fairly primitive bobbin mills.
Once the cotton spinning industry took hold in north England and central Scotland in the early 19th century, there was a dramatic increase in demand for bobbins in their millions. Bobbin mills sprang up across the Highlands wherever access was good, and operated on short-term exploitation of the local birch resource: hardly sustainable!
With increasing grazing pressure from recently introduced sheep farming and the development of deer forests for sport, these woods never had a chance to regrow, and many were lost. By the mid 19th century the era of the bobbin mill had ended, technology was moving on and the landscape of the Highlands changed forever.
Credit John MacPherson
Birch trees in folklore and placenames
Birch has an important role in Gaelic and northern European folklore, and is said to symbolise purity and renewal. It was part of the rituals around the Celtic festivals of Beltane and Samhain and other British folk traditions. In Scandinavia, one of their rune letters symbolises a birch tree, and ‘beating’ with birch twigs is still often part of the cleansing traditions that revolve around the sauna.
The Gaelic name for birch is ‘beithe’ and the Norse-derived ‘birk’ often denote places or features that are, or were once, associated with birch trees or woods throughout Scotland and northern England. In parts of the uplands where projects are trying to restore ecosystems, ancient name associations like these and for other common trees can give useful hints as to what landscapes used to be like.
The three different types of birch tree that you’ll find in Scotland
In this country we have three species of birch, which are distributed according to soil fertility, wetness and altitude. However, like many tree families where you get more than one species together, they tend to hybridise freely resulting in trees that have characteristics of both their parent species.
Silver birch (Betula pendula)
Mostly occupies lower altitudes with better-drained soils, and can be seen all over Scotland. It can be best identified by the graceful way the branch tips droop giving it a quite distinct appearance which of course is reflected in its Latin name. The bark is silver-white and papery when young, but becomes more fissured and darker with age. In the west, the bark can also be obscured by lichens. Generally, it’s less fractured and grizzled with grey than downy birch, and its leaf stalks and shoots are not covered with fine hair, but have small wart-like growths. Leaf shape is not a good way to differentiate between downy and silver birch as they can be both very variable.
Downy Birch (Betula pubescens)
As the name suggests, has furry down covering the leaf stalks and young shoots. It is frequently multi stemmed, has a ‘stiffer’ form and doesn’t weep like silver birch. It is able to withstand wetter and less-fertile conditions, and is therefore common in mountainous and moorland landscapes. In exposed situations its growth can get very twisted and stunted. There are those who argue that there is a different subspecies ‘tortuosa’ that exists at high altitudes and has an often-stunted, twisted growth and other features that enable it to survive in harsher environments. See more on this below.
Dwarf Birch (Betula nana)
The final native birch species, forming part of valuable montane scrub habitats. Growing to only around 1m tall in dense stiff bushes it is very recognisable with small round bluntly toothed leaves. It grows frequently on blanket peat and higher mountain slopes and like other montane scrub species, it is very vulnerable to grazing pressure and wildfire. Its distribution is largely confined to the Highlands in Scotland although there are small populations in the north Pennines. Along with dwarf juniper and montane willow species, it should be part of extensive areas on mountain slopes but like the mountain birch zone (see below) it has largely been lost. Through restoration projects, we are looking to rebuild this valuable and rare habitat in suitable locations and work with partners to promote its visibility and encourage others to do the same.
Credit Phil Formby
The mountain birch zone
There is a tree habitat called the mountain birch zone lying between 650 and 900 metres, which has largely disappeared from Scotland. Tiny remnants remain in areas like the Cairngorms, and various projects are currently looking to record, collect seed and expand this habitat before it is lost altogether.
The mountain birch zone should be the transition between pine, birch and oak woodland to true montane scrub habitat at the treeline in a natural functioning woodland ecosystem. The theoretical treeline in this country varies widely depending on exposure. A reduction in deer density in the Cairngorms has now allowed tree regeneration to reach up to the mountain tops, but on the northwest coast, exposure would reduce this. Either way these transitional habitats are important for biodiversity and fulfil important functions like natural flood management by reducing water run off from the hills.
Wildlife in birchwoods
Birchwoods contain a multitude of wildlife, some generalist woodland species but mostly those species that can make use of the small seed that birch produces and the multitude of insects on the bark and leaves. Unless there are other tree species present close by don’t expect to see red squirrels! In the northern rainforest and other large birchwoods expect to hear a different soundscape of treecreepers, all species of tits, siskins and redpolls as they flit amongst the canopy. Very Scandinavian. Open birch habitat is also important for diminishing populations of black grouse and woodcock.
Credit Peter Lowe
If you are in a birchwood in late summer and autumn expect to see a wide variety of fungi: my favourite foraging spots for chanterelles are all in birchwoods… all a close secret! Throughout the year you will spot birch bracket fungi that look like hooves growing out of the trunk. These traditionally have had many uses from razor strops to firelighters once dried.
So next time you see a birch tree, don’t just dismiss it. See if you can identify the species, and if you’re in the rainforest zone, look to see how many different lichens you can see on the bark of different trees. Lichens are actually very fussy and for some reason some trees have a lot more lichen growth than others due to micro habitat and bark chemistry changes.
Go out in the woods and see what you can find!
