If you're looking for the tracing logging files in Lync 2013 you're likely looking in the wrong place. In prior versions of Lync it was located here:

%userprofile%\Tracing
i.e.
C:\Users\<username>\Tracing

In Lync 2013, the client tracing folder in now located here:
%userprofile%\AppData\Local\Microsoft\Office\15.0\Lync\Tracing
i.e.:
C:\Users\<username>\AppData\Local\Microsoft\Office\15.0\Lync\Tracing

It makes sense that they'd move it here since Lync 2013 is tightly integrated into Office 2013 and that is where the Office suite has kept its data files for years. I've always preferred to have my root (C:\) folder as clean as possible will minimal subdirectories and the same goes for my user profile (c:\Users\tkeating) folder. So glad to see the change.

Well, this has been your helpful Lync 2013 tip of the day!