You used a lot of hard black in this--hex code 000000, no color at all--which is bad. Not only does that waste a lot of space, it distracts from the rest of the picture by creating voids where the viewer expects to see detail, but doesn't. You can fix this by replacing the black with very deep blue or deep purple, and adding a few lighted areas where moonlight is reflecting off things (like off the edges of tree branches, rocks, or pine needles). That way, almost all of the shadowed areas remain in shadow, but the shadows also have a color that fits the rest of the picture, and they look a lot more interesting.
Don't be sad. This is still a pretty good picture. But spamming 000000 is a bad habit to get into.