What rules of composition do you see in this photo?

To me this photo has a lot of tension in it, its not really using the rule of thirds, nor is it completely centering the subject. Its a fairly contrasty photo and makes use of positive and negative space and likely some of the similarity between the rose petals and wood grain patterns. Also used to great effect is the separation achieved through the very white of the rose petal against the complete black at the top. Ansel Adams photographs are often very subtle and difficult to pinpoint what makes them beautiful.