Tree of the month: December 2022 - Silver Birch

Each month we will be featuring a species of tree found on Parkwood Springs. Visit our tree of the month page for further details here. This month we will be highlighting Silver Birch.

The graceful, delicate-looking Silver Birch is actually very hardy. A ‘pioneer’ coloniser, it can grow up to 30 metres and, along with Rowan, it grows at greater altitude than other species. It can live for over 100 years, and supports more than 300 insects, including the Angle Shades and Buff-Tip Moth and in some areas the rare Camberwell Beauty Butterfly.

Silver Birch carries male and female catkins on the same tree, producing thousands of seeds in late autumn/winter, providing food for many birds, including Redwing, Siskin and Greenfinch. Caterpillars that feed on the leaves also feed many birds in spring. It is the favourite nest-site for the increasingly rare Lesser Spotted Woodpecker.

Several fungi live on the birch, including the Birch Mazegill and the Birch Polypore (The Razor Strop), the latter eventually killing the tree. The light canopy encourages several fungi, including the iconic Fly Agaric, to grow in its shade.

The bark typically develops diamond-shaped fissures as the tree ages, and the white bark sheds its layers.

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Each tiny nutlet on the catkins of Silver Birch can be carried up to a mile on the wind as they disperse in autumn and winter. The seeds are a valuable food source for several bird species.

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Some of the uses, past and present:
• The bark was used for tanning leather
• Native Americans used the wood for canoes
• Long bunches of the fine twigs are used for besom brooms and for fire-beaters
• The wood has been used for race-course jumps, plywood, veneers, skis, and tool handles.
• Lengths of bark used for roof shingles
• High in resin, the wood is used to light fires
• The resin is a source of waterproof glue
• The sap is used medicinally, as a drink and to make beer in much of North Europe
• Used herbally to treat inflammation, and kidney stones
• To be given the birch, using the strong twigs, was a common punishment for children and to drive out the ‘evil spirits’ for those believed to be ‘possessed’

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Some myths and legends: The Welsh associated the Silver Birch with love (the Welsh ‘Berth’ means ‘bright’) while residents of Colonsay draped twigs over their babies cradles to protect them from Fairies. They are important symbols in much of Russia and often thought to ward off evil spirits. Some Celtic tribes saw it as a Holy Tree. It is the First lunar month of the Celtic tree calendar and the Druids believed it to hold sacred powers of renewal and purification.

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Fungi associations: Silver Birch develop strong mycorrhizal fungi associations beneath the soil, as well as the ‘fruiting bodies’ we see above ground, both on the tree and growing under its light canopy (see Fly Agaric below). Here are some of the fungi closely associated with the tree.

The Birch Polypore is particularly interesting. It is one of two fungi carried on the belt of ‘Otzi’, the 5,000 year old animal-herder found preserved, buried in the ice of the Alps. He could have been carrying it for two reasons: it was used as tinder to light fires and also medicinally against intestinal parasites which were found in his gut. Also known as ‘Razor Strop Fungi’ the dried strips were used until recently by barbers to sharpen cut-throat razors.

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