How to hide the "Tree" dropdown menu from the Pages admin navigation on non-superusers?
Although Robin S´s module might "hide" the menu entry it is still accessible if you know the URL.
To restrict non-superusers and redirect them to another page after logging in, you need to do it different.
I wrote a module for that case which you can find at https://github.com/jmartsch/ProcessRestrictTreeMenu. It is not configurable yet, but you can change the code in the .module file.