[wp-testers] is_tree with no argument?

[Bryan Harley]

Can someone help me modify the "is_tree" snippet for the Conditional
Tags codex page, see:
http://codex.wordpress.org/Conditional_Tags#Testing_for_paginated_Pages

"is_tree" works great, except that I don't want to be required to
provide a page ID, currently you HAVE TO:  is_tree('2').  I just want
it to check dynamically if this is a page or sub-page: is_tree()

Any idea how to do this?