The bottom drawing was playing on the idea of the tree's over growing on the arch. Also there are quick illustrations of ruin layout above. Before conferring with the group i had already started with a circular ruin idea with an entrance archway.
I really loved the idea of having cartoony illustrated and simplified trees, not too hot on photo realistic designs like below. Although i think its important that i understand the structure of the tree and its roots before simplifying them as it makes you look for the detail and what stands out and what detail is important to keep.
This tree above on the right was growing on the side of a mound of dirt which is why you can see the roots.
This last drawing on the left was growing on top of a roof of an asian ruined building.
I guess the reason i wanted the group to do our own little environments is because you can move from one thing to the next, the variation between roles which you don't get so much of when just being a modeler for example.