So I have done a little stalking on other blogs and at roneyzone they have a wonderful little article about where else we have seen the tree…
1) It is on the door of the police car in the insignia
2) It is on the design of the police badge given to Emma by Graham
3) It is etched on the vase in David and Kathryn’s home when they are eating dinner (Skin Deep)
So obviously this tree or a tree is important.
Also found in my digging around that Nostos (in OUAT ep13 the siren was in Lake Nostos) is a Greek word meaning “homecoming” and is a theme used in Homer’s Odyssey, so I feel sure this perhaps goes with the something lost being found idea (a homecoming of sorts). A siren is also present in Homer’s Odyssey.
One last note, and I may a bit naive here, but after James coming to the lake and the switch back to Storybrooke and the stranger taking Emma to the well, my initial and automatic reaction was that the water from the well came from Lake Nostos. I couldn’t figure why they would make such a big deal about the lake in FTL and then show us the well in SB if there was not a connection.