Birch trees did not always have silver bark. There was a time when their trunks were the grey-brown of most other trees. It was sex that changed things. It always does.

Long ago a girl grew up in a village surrounded by thick forests full of all sorts of trees: elm, ash, beech, birch, oak, rowan, hawthorn, hornbeam. She loved trees and knew the forest well.

Unfortunately the girl’s parents were very strict and would not allow her to have a boyfriend. The men in the village were not good enough for her, they felt.

The girl was less picky and more hormonal. One day she arranged to meet a man. ‘Come to the ash grove north of the village at midnight,’ she whispered to him as they drew water from the village well. He nodded, too ashamed to admit he had no idea what an ash tree looked like. Instead he crashed about in the woods for an hour before giving up and going home.

‘He’s too interested in football to care about me,’ the girl thought, and set her sights on another. ‘Meet me at the stand of beech trees east of the village,’ she instructed as they were buying bread at the baker’s. This man also knew more about sports than trees, and didn’t even get beyond the willows at the edge of the village before he turned back.

The girl decided to make it as easy as possible for her next potential lover. ‘Do you know the old oak that stands on its own in the middle of the woods to the south of the village?’ she said as they waited for their flour to be ground at the village mill. ‘Meet me there.’ Surely everyone knows what an oak looks like. But no: the man stood under a lone elm, wondering if its wood would make a good cricket bat.

The girl waited under the oak tree and wept at the thought of dying a virgin. ‘My parents are right,’ she sobbed. ‘The village men are too stupid for me!’

She gave up on men then, until one day a stranger arrived. Not only was he handsome, but he also didn’t care much for sports, turning down the chance to play five-a-side football or cricket on the village green. Instead he wove the girl a daisy chain. She took this as a good sign, and invited him to meet her, though she decided to test him on his tree knowledge. Only a tree-loving man would do. ‘Meet me in the birch wood to the west of the village,’ she commanded.

The man agreed. Unfortunately, however, he was from the city, where even fewer people knew about trees. And being a man, he wouldn’t admit he couldn’t tell a birch from a beech. He simply trusted fate: if they were meant to be together, he would find her.

Now, the birch trees had had some of the other suitors stumble through them on their abortive rendezvous, so when the girl came to wait among them, they knew what might happen. Indeed, as it grew late and the man did not arrive, the girl began to weep.

He simply trusted fate: if they were meant to be together, he would find her.

Then the moon appeared from behind a cloud, lighting up the forest. Among the birches there was one tree with mutant genes that had made its bark a silvery white. The other birches had often teased it for being different, but on this night its difference became its strength, for when the moonlight struck it, it lit up like a beacon in the dark forest. Seeing its glow, the man made straight for it and there found the girl.

She was so relieved to have a lover at last that, in her post-coital bliss, she vowed to protect the silver birch from ever being chopped down. This protected status ensured not only its long life, but its propagation as well. After a time, silver birches became the norm.

They are still the best trees for a tryst.