This shot isn't bad and it fits the challenge but it doesn't hold me as an intriguing image. Maybe if you move in and got the bark on this tree? However there are other shots like that so maybe not. From your title I'm assuming you intend the rings to be the subject however it is the human tendency to look first at the brightest or most in focus portion of an image and the bark is where my eye keeps going.
A difficult angle to work with, but the DOF control is excellant. The image does demonstrate texture is various ways, but it feels flat and uninteresting.
interesting subject and nice texture. it maybe could've been shot from a different perspective or with a more shallow DOF to make it pop a little bit more.