Traversing trees with sparql?

This is a comment in the form of a question:

I would like to be able to select a branch of a tree structure (similar
to the DMOZ directory tree, where the tree is formed by traversing the
dmoz:narrow property).  Can this be done in sparql? If so can someone
provide an example.

Regards,

David H. Jones
Boeing Phantom Works, 
Mathematics & Computing Technology
425-865-6924 
425-865-2964 (FAX)
david.h.jones@boeing.com