Whatever the origins, recent or otherwise of the beautiful lyrics, this tune is probably pretty ancient, since it fits easily on the bagpipes [ I've figured out an arrangement so it can't be too difficult]. The scale on the pipes has slightly different intervals, that don't fit exactly with the "do-reh-me..." scale, which is probably why so many many pipe tunes don't quite sound right when played on other instruments,e.g the piano, and some of these tunes are seriously old. "The flowers of the Forest" which, legend has it, commemorates the dead of Flodden {1514} has been played, literally for centuries,and will no doubt still be played in the distant future,
Graham