DOCBOOK-APPS: changing table size

Hi!

I just started using docbook for documenting a software and its API.
I need to create html as well as pdf output. So far, so good... it
works quit well, using Saxon/FOP. My problem is, that I have tables in the document
that are too large to fit on the width of an A4 page in the pdf.
Is there an easy way to change the font size of the table for pdf
output but not for html?

Greetings,

Tobias