Can Towering Roots of the Jungle replace Presence with its Incarna even if its Incarna is already on the island?
Can Towering Roots of the Jungle replace Presence with its Incarna even if its Incarna is already on the island?
Yes. The Incarna leaves whichever land it was in and ends up where the Presence used to be.
This doesn't count as adding or moving the Incarna.