Some debris, more distorted wooden beams and planes on the ground to blend with a scene would add a lot of mileage. Personally, I'd like see the whole wooden support structure fatter around the rocks, and the base of the bell thicker as in the reference image.
I went and took a bunch of photos of wooden boards laying around my yard. This thing is starting to drive me crazy so I think it's time to move on to something else.
Coming along well. I'm not sure about the wooden planks getting lighter on the sides, it doesn't make much sense to me. A nice ambient occlusion or GI bake layer thrown on top of this texture at about 25-50% opacity would make a world of difference in making it seem more solid and massive, I think. Keep it up!