This thread had me stumped for a while and I was I thinking that Barry was barquing up the wrong tree! But now I'm thinking there may be a spinter of truth to his query. There are many references in folksongs to trees: the oak and the ash and the bonny whatever tree, and there's the blackjack oak, and they little to do with lumber or even kindling a good fire. Consider this typical verse:

Fair maidens take warning, take warning from me,
Never trust your affections to a green growing tree,
For the roots they will wither and turn into dust;
There's not a man in ten thousand a poor girl can trust!

But this verse may really get to the root of Barry's query:

I saw a flea heave a tree,
Fie, man, fie!
I saw a flea heave a tree,
Who's the fool now?
I saw a flea heave a tree,
Twenty leagues out to sea!
Thou has well drunken and who's the fool now?

Here we have a clear explanation of how the tree got out in the ocean. Well, maybe not out into the "middle" of the ocean but at least out beyond the horizon. At least the water is wide out there, and without a boat I cannot cross over...

Cheerily,
Charley Noble