i have a question, how do you get trees like the ones in your images. in particular the ones with just a black tree outline like the ones in this image you posted

is the tree background added in photoshop or are they models as well? they look gorgeous

@thomthom said:

Oh yea, it works very nice. It often makes the render pick up more details in the corners. But I'm vary of over using it.
The Dirt map is also nice.

can i ask what the Dirt Map is and how i can use it?