This Is Not A Dirty Joke.

Two tall trees, a birch and a beech, are growing in the woods. A small tree begins to grow between them, and the beech says to the birch, "Is that a son of a beech or a son of a birch?" The birch says he cannot tell.

Just then a woodpecker lands on the sapling. The birch says, "Woodpecker, you are a tree expert, can you tell if that is a son of a beech or a son of a birch?" The woodpecker takes a taste of the small tree. He replies, "It is neither a son of a beech nor a son of a birch. It is however, the best piece of ash I have ever put my pecker in."