­Tourach's Chant

Tourach! You're as bad as Theldon! Stop having broad colour hosing!

Also, this card sounds like it should be a sorcery, though the upkeep cost for continuing to chant for turns on end is kinda amusing.

­Tourach's Hymn - sorcery. Tourach's Chant - enchantment.

I actually see no problem with enchantments representing musical pieces. Discordant Dirge and cycle do this well. I think the upkeep cost makes it work.

Now these kind of color-hosing effects are obviously problematic, but you could easily remove the color specification from playing a Forest to playing any land and balance the numbers and still have a valid card. Though I'm personally not a fan of cards that punish playing lands there is something to be said about the fact that this lets you pay not only life, but also in creature resilience.

Alternatively, instead of a spell that deals hurts opponents who play forests, you could make this a spell that rewards you for playing Swamps. "Whenever you play a Swamp, target opponent loses 3 life unless that player puts a -1/-1 counter on a creature they control."