Birch Bark to seal ponds?

I was wondering if anyone has used birch bark to seal a pond?

I would think it would decompose.

    ¿Isn't the gley that seals ponds formed with anerobically underwater or under pond liner plastic or whatever decompsing vegetable matter?

    ¿Did not native americans use birch bark to boil water in?
    I have put in Spanish question marks because it can amuse people from other countries, they put in question and exclamation marks before and after sentences. agri rose macaskie.