There is an elven ancestor tree in the center of Bloodmoon Island on Reaper's Coast. Several Black Ring followers are trying to get something from it. Both the elven druid spirit (Quest: The Druid) and the Advocate (quest: The Advocate) want to get rid of them. And since the Black Ring cultists are not the nicest people walking around... Well, I was quite happy to get rid of them and then help the tree.
Note: Start the "The Druid" quest BEFORE doing anything else on Bloodmoon Island. Especially before fighting the Black Ring. Otherwise it may not finish.