Birch (Betula spp.) are pioneer trees (they were first to colonise after glacier retreat) and today still, make way for larger trees to grow as a result of their quick growth and relatively short life span (average of 60-90 years). Growing up to 30m, they nurture the soil as they break down quickly.
Amazingly the Bark with its high content of betulin (a substance with fungicidal properties) will out last the rotting wood, often you'll see a hollow, rotten tree with the bark still intact. Therefore, the bark is also great for making mould proof containers, as well as baskets and even as parchment for writing on - the species name 'Betula' is derived from the Sanskrit word bhurg meaning 'a tree whose bark is used for writing upon'. I often use its 'peeley' bark to start storm kettle fires with as it is a great tinder.
Left: image from jonsbushcraft.com
Birch bark has been used for tanning leather and for preserving ropes and nets. Oil tar can also be made from the bark (it is heated under airtight conditions; the final product consists of tar and the ashes of the bark) it is used commercially in ointments for chronic skin conditions.
The Wood itself is used for smoking meat and fish, making high quality artists charcoal and as it is light and easy to work with, has been used to make canoes, furniture, and toys. Officially a 'hardwood', birch was traditionally used to keep fires going in the distillation of whisky.
Catkins are the male and female reproductive parts (flowers). Birch is monoecious, meaning both male and female flowers (catkins) are found on the same tree, from April to May. Male catkins are long and yellow-brown in colour, and hang in groups of two to four at the tips of shoots, like lambs' tails.
The pollen can be a problem to hay fever sufferers. Female catkins are smaller, short, bright green and erect, between 1 and 2cm tall. The male catkins release their pollen which blows via the wind to the female catkins. After successful pollination, female catkins thicken and change colour to a dark crimson. Masses of tiny seeds are borne in autumn and dispersed by the wind.
Key Identification (ID):
There are around 60 birch species world wide, we have two main species here in Scotland; silver birch (Betula pendula) and downy birch (Betula pubescens) and I've yet to see Betula nana, a smaller, shrubbier variety that is found in the exposed areas of the highlands. Silver and downy also hybridise, so as with any wild plant or fungi, get familiar with different ID cues, macro and micro. Both B. pendula & B. pubescens have those distinct triangular black markings on whiteish bark and the bark peels off horizontally.
You can also see the many horizontal lines (lenticels) on the bark where the tree exchanges gas (right):
The scientific names help with their ID - Betula pendula is the silver birch, remember that it usually has whiter bark and mature trees' canopy structure from a distance are quite pendulous *does a flopping and bouncing arms movement*.
Before new leaves form in spring, you can best notice the small branches that are quite whispy and pliable too - once used for ropes, brooms, thatch and more. You can even make a tea from the Twigs; see Robin's birch twig tea recipe here. In Celtic mythology, the birch symbolises renewal and purification and bundles of birch twigs were used to drive out spirits of the old year.
Downy birch Betula pubescens has more grey-white bark and its canopy stands up on end more - a bit like pubic hair! Its all in the name. However this likely refers to the difference between the leaf stalks (where the leaves grow from) as they are slightly fuzzy with tiny, white downy hairs, silver birch leaf stalks are not. I have also noticed silver birch has small, wart-like bumps on these fine twigs, downy does not (as far as I have observed and read about)… take a close look for yourself!
Another key ID feature between the two is that the silver birch has a double-toothed Leaf edge (large and small serrations), and downy has just one uniform size of toothed edge along the serrated edge of the leaves. See if you can observe this as the trees start to open their leaves.
Silver Birch has mycorrhizal ('fungi-root') relationships with many Fungi, such as Fly Agaric, Birch Boletes, Woolly Milk Caps, Chanterelle and Penny Buns. Birch is also parasitized and slowly dies (or shall we say is recycled and transformed) as it becomes home to Birch Polypore (Fomitopsis betulina), Chaga fungus (Inonotus obliquus), and Hoof fungus AKA Tinder bracket (Fomes fomentarius).
Remember the mushrooms we eat are the 'fruiting body' or reproductive parts of the mushroom - their main myco-organism lives underground or in trees, usually out of sight apart from our friend Chaga, whose mycelium mass is on the exterior of the birch tree. All these fungi have amazing medicinal properties - much of which comes from the birch tree itself!
Birch polypore - technically edible but it is quite cork-like in texture and rubbery to eat - can be decocted in water to make a medicinal drink or as a stock in broth. Its potent medicinal actions make it a wonderful immune tonic and other benefits include its anti-inflammatory, anti-tumour, anti-parasitic, anti-viral, and anti-bacterial effects! Another way to prepare, store and use F. betulina is by extracting the 'active constituents' in alcohol for use as a medicinal tincture. Read more about birch polypore's chemical composition (some of which comes from the host - birch), in this study here, conducted by K. Sulkowska- ziaja et al in 2018.
This annually growing fungus (unlike other 'bracket' fungi that grow perennially), looks a bit like a pancake from a distance and you can also make a quick plaster out of its underside which has lots of moisture absorbing pores (polypore = many pores or wee holes). Harvest when the pores are white.
Ötzi the Neolithic Iceman (doing his thing over 5,300 years ago) was found in 1991, preserved in the alps on the Austrian/Italian border. He had on him; birch bark containers, hoof fungus and birch polypore thought to be for starting fires and to treat his intestinal worms.
Following the life force of the tree or plant and its cycle across the year, you can determine the best parts to harvest and when. This is a good rule for foraging plants in general, focusing on: leaves in Spring - flowers in Summer - fruits, seeds, and nuts in Autumn - roots & bark in Winter/ early Spring. There are of course overlaps and exceptions such such as Blackthorn or Coltsfoot that flower before they produce their leaves.
Spring - harvest the sap (collect in March after the worst frosts & before the tree leaves open): drinking as it is/ make syrup/ wine/ beer etc.
Spring/ early Summer - harvest the leaves (before they get tough or yellow): you can eat them raw but they are quite drying and bitter, make a water infusion with honey (tea), infuse into oil (I use infused birch leaf oil to make a muscle rub with), or add to vinegar in the same way.
Summer - harvest flowers/ catkins (not so common anymore): traditionally toasted in a hot pan, dried then pulverised through desserts, creams and to make beer with - mostly used as a flavouring or famine food.
Autumn - harvest fruits & seeds (catkins in this case) "
Winter/ early Spring - harvest bark & twigs (being mindful not to take too much or badly injure the tree) or purchase from a sustainable source: outer bark made into anti-cancer medicine, inner bark (cambium) layer can be made into a type of flour or soup thickener as a famine food.
Image - Silver Birch (Betula pendula)
Medicinal actions & uses:
Anti-inflammatory, Antiseptic, Astringent (tightens tissues), Bitter, Chologogue (promotes bile), Diaphoretic (makes you sweat), Diuretic (helps rid wastes via your urine), Laxative.
Sap - drink fresh as a tonic, used to flush the body of wastes (without depleting you of salts as it is high in potassium), it detoxifies and invigorates.
Leaves - used as a tea it will cleanse the body, ease fevers, clear kidney stones, urinary gravel and help with fluid retention, cystitis, arthritis, rheumatism, and therefore your skin will look clearer too. Infused in oil it will help cellulite, aching muscles, eczema and psoriasis.
Bark - can make a tea (30g/1L water for 20mins)* or tincture (using alcohol to extract alkaloids that water can't dissolve), will help treat fevers, ridding you of wastes and when applied topically in the form of a birch tar oil it can treat skin conditions such as eczema and psoriasis.
*As advised by Grass Roots Remedies Herbal Clinic.
Tapping birch sap - the less invasive, branch method!
- The time of year that is best (here in Central Scotland) is after the worst frosts and before the tree leaves come out, usually mid-March.
- Find a healthy, mature birch tree whose trunk is more than 20cm across (silver or downy, they have the same potency). Consider choosing a healthy and clean looking habitat.
- Be thankful to the tree and imagine what you are going to do so the tree can sense your intensions and your joy for its amazing properties. If something doesn't feel right, choose another tree.
- Look for a downward pointing branch that is no thicker than your thumb. Not all trees will have this.
- Tie first the twine under a 1L plastic bottle lip, leaving two long tails, then cut the downward facing branch with clean secateurs. Slip the bottle over the cut branch and tie securely with the twine (ideally above a notch so it doesn't slip).
- Check the drip rate (count the seconds between drips) and monitor the sap flow each time you visit so you know how much that particular tree puts out over time. Collect the sap when the bottle is near full, usually after 1 day. To keep the bottle tap in operation without removing it (easier with 'bendier' branches), tilt the whole branch with the bottle still attached and pour the sap into a cup or bottle (pour through a small tea sieve to filter out any lichen that may have fallen in), and leave it on for up to another 3-4 days for further collections.
- If possible, when you remove the bottle, bend and slightly crack the branch above the cut to help the tree heal faster (mimicking a natural tare or break).
- Thank the tree again and say: "May your roots be strong and your life be long!"; something an unfamiliar tree once said to me when I was wondering how to greet its magnificence.
References & Resources
Milliken, W. & Bridgewater, S. (2013). Flora Celtica, Plants and People in Scotland. Birlinn Ltd.
Burton-Seal, J. & Seal, M. (2009). Hedgerow Medicine, Harvest and Make Your Own Herbal Remedies. Shropshire: Merlin Unwin
Kenicer, G, J. (2020). Scottish Plant Lore, An Illustrated Flora. Birlinn Ltd.
Hopman, E. Evert. (2008). A Druid's Herbal of Sacred Tree Medicine. Destiny Books, Inner Traditions International.