Cleanest Dirty Joke Ever!

It is hard to find a joke today without a dirty word or two in it,
but, here is one:

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?"
Just then a woodpecker lands on the sapling.
The birch says, "Woodpecker, you're 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."