Due to their desirable features and aesthetic value, silver birch trees are often planted in gardens and it is in exactly this location that I fondly recall my first memories of this species. At my family home in Kent we were lucky enough to have two mature silver birches in the garden, perfectly placed to support a hammock. As children, my sisters and I used to lie directly under their gracefully drooping branches and snooze away the long summer afternoons – sheer bliss! I even sourced the leaves for this months leaf rubbing from an obliging tree, who’s origins may have been in someone’s garden but who’s branches drooped down close enough to the public pavement for me to grab my sample!
The silver birch is a slender and elegant tree. It’s relatively fast growing during its early years and prefers light, dry and acidic soils. Its most distinguishing feature is the white peeling bark with black fissures. The manner in which this species sheds its top layer of bark makes it almost tempting to tease away the white to expose the black underneath.
Compared to other deciduous trees, like ash and English oak, it’s a smaller tree, typically reaching a maximum height of 18–25 metres. Its drooping branches with long slender buds burst into life around March/April each year to reveal intricate (1) triangular shaped leaves with (2) double-toothed coarsely serrated margins. The leaves are initially bright green before settling to a pale green for the majority of summer. As autumn creeps in the leaves turn yellow/brown and start to drop at the end of October.
All birches are monoecious, meaning that each individual tree has both male and female flowers. The trees reach sexual maturity around 5 – 10 years and flowers appear at the same time as the new leaves. The flowers are called catkins and are pollinated by wind.
Interesting Fact: A catkin contains hundreds of seeds and a large tree can produce over 1 million seeds a year!
It’s close relative, the downy birch can be easily mistaken for silver birch. Here are some key features to allow you to tell the two species apart:
- Leaf shape: downy birch have rounder leaves and only a single row of teeth on the leaf margin. Silver birch have a double row of teeth and are more triangular.
- Twigs: Silver birch have small white warts along their purple-brown branches whereas downy birch branches are slightly hairy.
- Branches: Silver birch branches are more droopy.
- Cytologically: Silver birches are diploid (have two sets of chromosomes) compared to the downy birches four sets (tetraploid).
Silver birch have high a conservation value – their light, open canopy with small leaves provide shade while still allowing the sun to penetrate through to the woodland floor. A varied ground flora can be found below, particularly mosses, grasses and flowering plants (including primroses, bluebells and violets).
The roots of birch trees have mycorrhizal associations with several species of fungi. The symbiotic relationships between the trees and fungi are of benefit to both parties. In autumn birch trees produce 3-4 tonnes of leaf litter per hectare per year – releasing nutrients into the soil.
The silver birches microhabitat provides ample food for a wide range of insects and birds too. At least 334 different insects are known to feed on birches, and insectivorous birds such as chaffinches, tits and robins are characteristic of birch woods. The catkins further supplement the birds’ diets in late autumn and early winter.
Domestic animals also benefit from the silver birches ability to withstand wind and hard frosts – providing reliable shelter for animals such as sheep in winter.
In Celtic mythology the birch came to symbolise renewal and purification, perhaps originating from their early display of leaves in spring. The Celts used bundles of birch twigs to drive out the spirits of the old year and gardeners still use birch brooms to ‘purify’ their gardens. Birch also has a strong association with love and fertility – according to a medieval herbalist the birch is ruled over by the goddess Venus and Scottish folklore suggests that a barren cow herded with a birch stick would become fertile!
Historically birch was credited with several medicinal properties. The leaves are diuretic and antiseptic and can effectively treat urinary tract infections. The sap is said to treat rheumatism and skin complaints.
Due to its abundance in Scotland, birch timber has been traditionally used for houses, furniture and carts. Drawing on the renewal symbolism, baby cribs were made of birch wood too. The sap can even be brewed into wine and beer – silver birch wine is still commercially made in Scotland!
Other parts of the UK use birch more sparingly, it is considered to have limited commercial value and oak is preferred for timber. However, birch remains the prime timber for racecourse jumps and traditional broomsticks.
Birches have a shallow root systems, making them susceptible to climate change and extreme weather events. For example, there was significant die back of mature silver birch trees during the droughts of 1976 and 2003. The rust pathogen Melamsporidium betulinum is associated with retarded growth and increased mortality, and two canker fungi are linked to the dieback of silver birch.
Quick silver birch facts…
|UK abundance:||Common (most common tree in Scotland and third most common in the UK)|
|Habitat:||Gardens, parks and woodland|
|Maximum age:||> 0 years|
|Mature height:||Up to 25 metres|
|Major threats:||Disease and climate change|
|Uses:||Furniture, broomsticks and wine|
Hannah Cole, Conservation Communications Intern