There is a significant amount of detail loss there, not sure about that.

Then you might want to try out my script that sets up proxies (http://gennyx.blogspot.com/2012/10/genproxyplop-version10.html).

/end shameless self promo <3

I don't know about that dof, most of whats in focus is tucked away to the side.

Gtfo! That looks great! You've had your nose to the grindstoned eh :). It's paying off. Only thing that that I can say is that the tree trunk silhouette is pretty smooth for such a bumpy looking bark...