Since this thread has re-appeared, I'll add a little more to it as I have access to more references these days.

The song is listed in the Roud Folk Song Index at number 1919; two examples from Ireland (including the one published by Tom Munnelly), one from London (presumably learned in Ireland), two from Canada, three from America (New England) and one from Scotland. Of course this reflects only "collected" examples; if the song is still widely current in Ireland, then specialists in that field would be doing us all a favour if they were to tell us more about it.

For myself I doubt any real connection to The Old Oak Tree (there is more in common with The Bloody Miller), but Tom Munnelly is far more experienced than I am.

A Newfoundland example can be seen online, with a short sound sample, at

MacEdward Leach & the Songs of Atlantic Canada: Pat O'Brien

There is some additional commentary in The New Green Mountain Songster, but two-thirds of it is speculation or not directly relevant. Printed examples don't much differ, which does suggest a broadside source; though none seems so far to have been identified.