I've seen lots of theories about all sorts of pieces of the mural from the trailer, from the idol to the dark and bright half-circles and more. This includes theories about what the tree might be - it's the twisted tree from the Emerald Graves, it's a dahl’amythal (the tree Dalish keepers cut their staves from), it's something we haven't been introduced to yet. But my personal favorite theory is that it's a representation of a vhenadahl - the Tree of the People that grows in the center of most alienages - and, additionally, a representation of modern elven culture as a whole, as seen by Solas.
( i suspect you have questions )
( i suspect you have questions )