Danny Spooner did an entire hour workshop on Celtic tree songs at this years National Australian Folk Festival, including the exploration of Jack in the Green and his evolution into Robin Hood. Robyn Williams (hope I spelt that right) has a woodcutters song I think

Oak logs will warm you well That are old and dry Logs of pine will sweetly smell But the sparks will fly etc.

Not exactly your celtic ambient faerie ring plant an oak over me kind of thing though.