Birch leaves and birch bark

The slender birch with its pale bark is commonly noted for its many benefits. It symbolises youth and spring, and is said to keep both humans and animals strong and healthy. Indeed, birch leaves and birch bark have vitalising effects on both the human and equine organisms. Birch leaves have mild diuretic effects, helping to flush out the kidneys and bladder and making them ideal for spring detoxes.

Where do birches come from, and what do they look like?

Birch trees do not make great demands on their environment. They grow in dry, rocky places just as well as in meadows, moors, mixed forests and clearings. The birch is a deciduous tree that grows extensively in Europe and Asia. Because it grows quickly (up to 7 metres in 6 years), it is often planted in parks and gardens. Mature birches can reach 30 metres, with light, pyramid-shaped crowns. Of special note is its smooth, white bark, which peels off from the trunk in strips. There are about 60 different species of birch worldwide. The silver birch (Betula pendula) and white birch (Betula pubsescens) are the species primarily used for therapeutic purposes.

Birch leaves are diamond-shaped and pointed with serrated edges. When still young, the leaves are soft and light green. They bear resin glands and have a slightly sticky feel, whilst older leaves are smooth and shiny. From April to May the birch puts forth both male and female blossoms that are easily distinguishable from each other: the male blossoms are hanging catkins that are 6–10 cm long, the female blossoms are erect, 8-10 mm wide catkins that are 2-4 mm long. Unfortunately for allergy sufferers, a single tree can produce up to 100 million pollen grains, and birch pollen is one of the strongest and most aggressive tree pollen allergens. After flowering, the birch puts forth an enormous number of fruits that resemble small, winged nuts.

Birch wood is light, yellowish or reddish and has little value as timber because it is not weather-resistant. As firewood, however, it is quite popular, as it needs almost no spark to ignite. 

Birch trees are more resilient than they appear. They survived the last Ice Age because they are quite resistant to cold and can withstand temperatures to -40°C. The birch converts starch within its branch and trunk tissue into oil which acts as an antifreeze.

Which parts of the birch are used in phytotherapy?

Birch leaves (Betulae folium) are gathered in May and June and then air dried. They have a slightly aromatic scent and a somewhat bitter taste. They are used to make tees, tinctures and extracts.

The use of birch bark (Betulae cortex) is documented in many different cultures. Strips of the soft, pliant bark were once used to dress wounds. Today soft, pliant "birchbark" is used for dry extracts or oil. Birch bark's white colour comes from the active substance betulin, which is stored in the bark and protects the tree from predators and extreme temperatures.

The unopened birch buds (Betulae gemmae) are gathered and dried in winter and early spring. These have detoxifying and cleansing effects.

Birch sap (Betulae liquor) is obtained by "tapping" a trunk that is at least 20 cm thick between March and May. This involves drilling into the trunk, collecting the liquid and resealing the hole with tree wax. About 3 litres of liquid may be obtained from a trunk without doing damage to the tree. The delicious, refreshing birch sap was once a popular remedy for cleansing the blood as part of spring cures. It was also applied externally to treat skin problems and to promote hair growth. It contains sugar, organic acids, and protein substances, and can be fermented to make an alcoholic beverage.

Birch charcoal is made by burning birch wood with a low supply of oxygen. It has binding properties and is effective in treating hyperacidity, gas, and diarrhoea.

Birch tar is obtained through dry distillation of the bark and branches. This tough, black-brown liquid has a typical "smoky" smell, and is an old folk remedy for skin problems, although it can also irritate the skin.

Caution: Not everything with "birch" in its name is good for animals! Birch sugar (xylitol) is a sweetener that doesn't come from birch trees – it is produced from agricultural by-products and is lethal for dogs!

Superstitions regarding birches and livestock

In Celtic Druid traditions, birches were used somewhat brutally on livestock. Whipping an animal with a birch rod was supposed to transfer the tree's life force to the animal, ensuring good health and fertility. In some regions of Europe, birch branches were used to drive livestock to pastures after the winter . A birch broom that had been used to sweep away spider webs would be placed on an ailing body part. Birch branches hung over stable doors were also said to keep away witches, evil spirits, misfortune, and vermin. The jury is still out on whether a horse's stable will really remain free of pests and parasites it is swept, accompanied by bell ringing, with a broom made of birch brushwood that was cut at Christmas...

What are the active substances in birch leaves and birch bark?

Birch leaves contain 2–3% flavonoids, which increase urine output. The plant extract is especially rich in these secondary plant substances. The leaves also contain phenolic acids, tannins, triterpenes, essential oil, and minerals. The diuretic effects of birch leaves have no negative impacts on mineral balance! Birch leaves are used to flush out toxins in bacterial and inflammatory urinary tract infections and boost the metabolism. Tests have shown that birch leaf extract can also lower fevers.

Dried birch bark consists of approximately 34% betulin, a white, odourless, fat-soluble substance. Numerous studies have proven betulin's anti-inflammatory, antibacterial and wound-healing properties. An ingredient found in creams and skin oils, the substance stimulates movement of the immune cells, accelerates the healing of wounds, and promotes regeneration of the skin. Some tests have shown the positive effects of betulin on the metabolism, in particular in relation to improved insulin sensitivity. Further studies are being carried out to determine whether betulin is effective in treating melanomas. Birch bark also contains 4–6% essential oils.

What canine and equine ailments can be treated with birch leaves and birch bark?

The diuretic properties of birch leaves help to relieve infections and inflammations of the urinary tract and kidney stones. The quite gentle effects of birch leaves make them ideal for use in combination with other diuretic and detoxifying herbs such as stinging nettle and dandelion. They can be applied externally to treat eczema and wounds. Birch leaves stimulate the metabolism and help relieve chronic skin conditions. Horses and dogs can benefit from a springtime cure with birch leaves to get the metabolism going!

Tip: Fresh young leaves that are still shiny and sticky can be added to feed raw.

Externally applied birch bark extracts support the regeneration of irritated skin due to itching and eczema.

Caution: Preparations made from diuretic herbs should not be used long-term. Do not exceed the manufacturer's specified period of use!
Do not use birch leaves on animals suffering from oedemas caused by weak heart or kidney disease!

Sources and further reading

• rendieck-Worm, C., & Melzig, M. F. (2018). Phytotherapie in der Tiermedizin. Stuttgart: Georg Thieme Verlag KG.
• Hensel, A., & Zahn, T. (23. 11 2017). Deutsche Apotheker Zeitung. Birkenrindenextrakt zur Wundheilung, S. 34. Von Birkenrindenextrakt zur Wundheilung: https://www.deutsche-apotheker-zeitung.de/daz-az/2017/daz-47-2017/birkenrindenextrakt-zur-wundheilung abgerufen
• Redaktion. (31. 01 2014). Pflanzenforschung.de. Von Birken Wirken: https://www.pflanzenforschung.de/de/pflanzenwissen/journal/birken-wirken-forscher-untersuchen-die-heilende-wirkung-10197 abgerufen
• Reichling, J., Gachnian-Mirtscheva, R., Frater-Schröder, M., Di Carlo, A., & Widmaier, W. (2008). Heilpflanzenkunde für die Veterinärpraxis. Berlin-Heidelberg: Springer Medizin Verlag.
• Wick, B. M. (Juni 2017). Karger. Von Schweizerische Zeitschrift für Ganzheitsmedizin: https://www.karger.com/Article/FullText/475587 abgerufen