Project 2B - Rendering issues

I am currently having rendering issues; so far it is rendering at 30 minutes per frame, after doing the math there is no way I would finish in time. I am going to cut down on rendering but am worried that it will ruin my project. I think it is the amount of trees in my scenes because my first scenes (without trees) rendered fairly quickly. It could also be the physical sun and sky because that is also not in my first scenes.