Great job just getting that many trees to stand up together! You can definitely get a better arrangement. Too much space between too many of the trees. Just my personal take on it and I know it's very subjective to the viewers perspective, but I do a lot of forest plantings and I do understand the difficulty involved in getting a good layout.
A great help for me in refining my forest attempts is the book, "Forest, Rock Planting and Ezo Spruce", by Saburo Kato. I think stonelantern.com has copies for sale. If you're going to do forests you'll love it.
