This is pretty nice. I might do two things a little differently. First, I'd crop a bit off the bottom to put thereby emphasizing the trees more. Second, I'd crop one of the trees off, probably the one on the far right to make an odd number of trees. Why an odd number? Because being human, we always like to divide stuff into equal parts, even lovely pictures. If the # of trees is odd, the viewer won't consciously or, more likely, subconsciously do this.
Beautiful image. I especially love the deep foreground. It reminds me a bit of Andrew Wyeth's Christina's World. Not totally sold on the vignetting, though.