"In early Celtic mythology, the birch symbolised renewal and purification. Bundles of birch twigs were used to drive out the spirits of the old year, and gardeners still use the birch besom, or broom, to 'purify' their gardens. It is also used as a symbol of love and fertility. In Scottish Highland folklore, a barren cow herded with a birch stick would become fertile, and a pregnant cow would bear a healthy calf."
(The Woodland Trust: https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/a-z-of-british-trees/silver-birch/)
