In To the River, Olivia Laing tell us about birch pollen being carried by the wind all the way from Jutland to Yorkshire. When doing a small-scale investigation into birches and pollination I came across this very intriguing information:
When the German botanist and physician Rudolf Jakob Camerarius (1665-1721) first published the evidences of sexuality in the flowering plants, he was faced with the necessity of proving that the wind could carry pollen from one flower to the other.
Strangely enough, says Conway Zirkle, most classical and medieval philosophers believed that certain mammals and birds could be impregnated by wind, although they were ignorant of the wind’s function in the cross-pollination of the flowering plants.
I do not quite know how to connect pollination and love, and being impregnated by the wind … well, – to me it sounds more like a threat than a lustful event. But birches and love – thats a different story:
(...) Earth's the right place for love: I don't know where it's likely to go better. I'd like to go by climbing a birch tree, And climb black branches up a snow-white trunk Toward heaven, till the tree could bear no more, But dipped its top and set me down again. That would be good both going and coming back. One could do worse than be a swinger of birches. - Robert Frost