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, but 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 and 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 poked my pecker into.'