This flag/symbol is meant to portray all of the values of Asgardia.
The trees reflect 2 things:
1. With some research I found that the top world of Æsir is symbolized by a tree (reflecting Asgardia).
2. The tree is meant to show both the growth into space as well as showing our roots being reflected/based on Earth.
The division between the trees is the Yin Yang symbol for balance. It also represents the break from Earth into Space as an independent nation.
The 7 stars, each with 7 points, surrounding the emblem reflect the 7 continents on Earth, encompassing all nations.
Lastly, the Olive Leaf represents peace, and its orbit around the symbol in the middle is meant to reflect Asgardia's peaceful orbit around Earth.
The Olive Leaf wrapped around the symbol is also meant to reflect that the nation is governed by peace.