Is the framerate much better when you don't have moving/swaying trees/plants?
Yes,sure.
Does the arrangements of trees/bushes change whenever you reload the level? or does it create a file to 'remember' what the arrangements were?
When you find an arrangement that you want, is there a way to save it?
My english very bad but i guess i understand your question.
Tree and brush creating is automaticly but if you reload level,does not change arrangement of tree&brush etc.. Tried demo.
And friends, if your need a performance;
reduce tree & bush number and use d3d_triplebuffer.
Thanks for all comment!