I just tested now, if the trees are set on a different layer they are drawn on that layer specifically. It's just that you need a camera drawing that layer in order to draw your trees. But that is problematic, since the trees are going to be drawn on top of everything. So be careful on how you plan to manage your trees. If you wish for different culling distances, better set them per-layer or something. But in the very near future I hope that I can implement cascade culling distances for different tree types with some nice optimized tricks in order to lift the need of having many cameras, layers and all that kind of spagetti. I'll post more probably Saturday on the subject.