Our native Silver Birch, Betula pendula, is a popular tree. It is the tree of choice in a variety of both countryside and urban settings. It tolerates a variety of soil conditions, apart from extremes of wetness and drought. Its medium-sized, upright and airy stature allows light to filter through to plants in the understory. As a natural pioneer species, could it be the ideal resilient and versatile tree for climate change planting schemes? Does it have a role to play in Natural Flood Management? Could it help prevent waterlogging and soil erosion, by slowing the flow of rainfall from higher ground?
Silver Birch is favoured as a street tree in open grassy areas on new housing estates. Selection of a smaller growing variety is advised. The Silver Birch’s upright stature, hanging branches and roots are viewed as less problematic than many other tree species in residential areas. The white trunks offer all-year interest, reflecting light even on dark winter days. They provide welcome summer shade. The various Birch varieties are generally not as prone to disease as Ash and Oak with natural chemical defences against excessive insect damage, while still supporting biodiversity. (One obvious disadvantage is that birch pollen can be a particular issue to allergy sufferers).
Mixed Woodland and Wind Resistance
There is an established tendency to plant Silver Birches in single species avenues. This may leave them vulnerable to the anticipated extreme winds under climate change. Silver Birches are generally regarded as resistant to both wind and frost. Following the winter’s major storms, I noted that Silver Birch fared better in mixed woodlands. I spotted a number of toppled Silver Birches alongside a known windy, open stretch of the M4.
Birch trees are prized as habit-sweeteners. They are recognised for drying out and reducing the acidity of wet, moorland soils. They are used to reclaim spoil heaps in mining areas (Ashmole 2006 via Milner 2011). The heavy 2020 winter rainfall demonstrated the increased risk of landslides in Wales for example, raising painful memories of the 1966 Aberfan disaster.
© Karen Netto (Andrews)
References and Further Reading
Environment Agency (2017): Working with Natural processes to reduce flood risk – The Evidence behind Natural Flood Management. Publishing Service gov.UK Last accessed 2 April 2020.
McDonald, Henry (2020) Effects of Storm Dennis spark fears of Aberfan repeat in Wales. The Guardian. 19 February 2020. Last accessed 2 April 2020.
McLean, Iain (2009): Lessons from the Aberfan Disaster and its Aftermath. British Academy Review, Issue 12, 2009. (Based on book Aberfan Government and Disasters). Last accessed 2020.
Milner, Edward (2011): Trees of Britain and Ireland. Natural History Museum.