Auto?
Best bet is to pick up a book and find out how the different settings change the result. Better yet take a class.
That said, for shooting in the woods I'd probably default to Aperture priority and run lowest f-stop my lens permits. Set white balance on shade/cloud (I don't shoot raw so I try to get wb right, and will usually err on the warmer side). Run lowest ISO possible to get desired shutter speed, although you will have to bump it up (1000+) if you want to freeze a moving subject in low light, even with a fast lens.
If none of that made sense, return to the top of this post.