One generic estimate for the number of sheets of paper produced per tree is 8,333 (meaning paper without a significant amount of recycled content). This statistic comes from the J. Assoc. Legal Writing Dirs., Fall 2010 at 195. For dramatic illustration, the author took data from 2008 for the more than 61,000 appeals filed in federal courts. After eliminating some of the appeals and making some assumptions, the conservative estimate was that those appeals consumed 8,233 trees, the equivalent of more than seven acres of deforestation.
Your law department should calculate how much virgin paper it consumes each year and translate that into trees felled. To borrow from Joyce Kilmer’s well-known poem, “I think that we shall never see a printout pretty as a tree.”