How to make your public tree appear on your profile:
1. From the “Collaborate” drop-down menu, choose “Public Profile”.
2. At the bottom left of the next screen, choose “Edit your preferences“.
3. Go toward the bottom of the next screen and under “Public Profile Preferences”, choose “update these settings”.
4. On the next screen, choose "Show links to any information about the public member trees I have submitted (will not show any personal family trees that you have not shared publicly)".
EDIT: I just saw that on this last screen, you can also opt to hide photos and stories attached to deceased people in your tree. Those who have kept their trees private to avoid photo "stealing" could use this option and make their trees public.