I personally don't think you should be doing all this post work this early. You have a nice sketch plan up the top and yet you have one rock, a tree (which is good and can be used a bit) and now your'e in post processing. I would start blocking the whole level out first, get a few types of rocks and start shaping it out.
This is my going to be my first attempt at a full UDK level. Seems like a big feat but I'm ready to take it on. Down below is a very simple Photoshop map of the forest layout. I am sketching up a detailed one at the moment and will be posting that shortly. Layout_rough: Rocks (so far): Zack Dembinski
the scale is a little off but that's not what was bugging me. compared to the style of the rocks and the tree trunks the leaves come across as looking a lil plastic. but as BIG suggested once you smooth out the planes it should look alot more natural. cant wait to see this done! very realistic thus far