Arkkard
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Arkkard, it depends on what stage you're at. If it's the first stage, then the sequence is:
1. Find a large tree near Winded and approach it to investigate.
2. Talk to the dryads in the treehouse nearby. You won't learn much.
3. Go back to the tree and stand there for a few turns.
I'm walking around the Tree, but it's not helping. I remember investigating it with the Monk, but that was a long time ago. There's no dialogue option with the Dryads. The last line in the quest is: "Unusual trees have not been found."