Cool photos man. Is your emphasis on nature only, or do you want to spread it out? When I was in Art School, for my photography classes, I did nude photos of college women only. Boy, was that fun.

I slightly felt a bit like a porn director, cause my friends and I would hold auditions and shit--all for free too.
But, I dropped out of Art School to pursue something more academic--it was fun while it lasted. Best of luck to you in your hobby/future photography career.