It may be a relatively dark photograph, but the aspect I like about it is the depiction of the tenacity of life as shown by the lone tree in an expanse of eroded limestone rock. The darkness of the photo contributes, I think, to that theme; life's footholds can be tenuous. I also like the smooth transitions to different densities in the sky, and it's fortunate that the shades within the tree are such that it stands out well from its background.