What I would propose is not elegant.  But it would work.

As the periodicals are in closed stacks, a staff member has to pull them.
 I presume that you have the patrons fill out a request form when they
wish materials from closed stacks?  If this is the case, *keep* the call
slips, and analyze them periodically...

John Mead, Assistant Librarian, Oregon Historical Society Library, 1200
SW Park Ave., Portland, OR 97205 (503) 306-5245 johnm@ohs.org

"Outside of a dog, man's best friend is a book; inside of a dog it's too
dark to read."  Groucho Marx