Corrupted Roots doesn’t care why the enchanted land becomes tapped. If that land changes from being untapped to being tapped for any reason, the ability will trigger.

Corrupted Roots can enchant only a Forest or a Plains. It checks the enchanted land’s subtypes, not its name. If at any time the enchanted land is neither a Forest nor a Plains (due to Unstable Frontier’s ability, perhaps), Corrupted Roots is put into its owner’s graveyard as a state-based action.