So spent most of last night and this morning reading, watching some more Terragen 2 tutorials. Found a very good resource site where I could download pre-made objects. Trees, plants, vegtation etc...
Just got a simple autumn tree and fallen leaves, figured out how to change the heading off the sun as well, the tree shadows are a nice touch.
Next think I want to accomplish is a snowy alps scene and i'll be starting on a 3D model today hopefully so stay tuned.