Welcome newbie!

I've tried it with birch bark with some success. But you have sliver it, peel it off to one layer thick and tear it into very find shreds. As I said, some success, but I'd have to not be too desperatly in need of fire.

I've got a bunch of birch around here. I've never heard of birch polypore, now I'll have to see what it looks like and if I have any of it available. But I'm still looking for tinder fungus...