Wednesday, 28 November 2012

Silver Birch

Our pocket park in Byfield boasts several birch trees and they are particularly attractive at this time of the year. One of the first songs I learnt at school was a setting of a poem by Edith Nesbit:

  The silver birch is a dainty lady,
  She wears a satin gown...

Despite its delicate appearance the silver birch is as tough as old boots and, as the last ice age drew to a close in Britain, birches were among the first trees to move into the bleak landscape.

In terms of wildlife it is a valuable species. In summer I can depend on finding the bug Kleidocerys resedae on its branches. A noisy and smelly little insect, it is one of the first species to come to the attention of people interested in such creatures. The Birch Shieldbug Elasmostethus interstinctus is also common as is an aphid, Euceraphys betulae, whilst in a single birch catkin I found 14 galls caused by the fly, Semudobia betulae. I mention the Latin names, not only because some of these insects have no common name, but because the specific name "betulae" refers to the birch tree itself, Betula pendula.

My photograph shows the largest and probably the oldest birch tree in the pocket park but, although this tree is probably around 30 years old, birches are not long-lived. Fungi attack them from quite an early age and bracket fungi are often a sinister feature of their trunks.

Druce's 1930 Flora of Northamptonshire describes Silver Birch as "rare as a native tree" and, significantly, John Clare makes no mention of it. Most of our trees are probably deliberate plantings or are seedlings from garden specimens.

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