Scott Lowrey wrote

If I'm descending slowly with a relatively nose-high attitude - say, in
preparation for a short field landing - does the high angle of the pitot
tube have any effect on indicated airspeed? (I suppose all designs are
different - say this is a 172.)

Yes, and this difference can be found in the flight manual. In early
C-172s, the difference can be 10 mph or more. The difference is the
difference between Indicated Air Speed (IAS) and Calibrated Air Speed
(CAS). At a CAS of 52 mph, a C-172B will indicate only 40 mph. In the
pilot's handbook for this early C-172, CAS was called "true IAS".
I certainly hope that you aren't already a pilot asking such a basic
question!

Bob Moore