Fiddler On the Green isn't forest metal. It's just a metal ballad. I don't get it; is it because he's singing about people out on a green heath, or something? I mean, all metal bands have that kind of stuff? What signifies "forest metal?" It sounds like a bunch of bullshit to me.
By the way InFlames, Zeppelin did write a bunch of material in their cottage Bron-Yr-Aur that they used for a bunch of later records.