Found by Valhalla of Morningthaw: I found a "Tree" in the desert, it looked like a pile of rocks, and its description read "A rock". below is the message I received when handing the "Tree" to the Stone Craftsman.
You allow Stone Craftsman to examine your Tree.
You hand over 1 of your Trees.
Stone Craftsman tells you, "Thank you human, this will do nicely. Before long we'll have this place filled with little benches to sit on."
Lore & Dialog
Stone Craftsman tells you, "I have come here to show my support of the upcoming marriage, lending a hand with what I know best. I need rocks so that I may form them into benches fit for tiny human forms."