Despite all advantages, the volume of paper doesn't seem to be decreasing
. Everybody still prefer a "hard copy" for maximum security/guarantee. If it's true that paper documents get decomposed with time it's also true that computer's hard discs / cds / dvds / blu-rays seem to have similar problems like data corruption.
The true is that there isn't any medium that assures eternity because time takes everything sooner or later.
If pharaohs had digital media do you think such things would still be readable today? Most Likely not :)
But keeping trees is important so the digital media can be transferred to stronger mediums as they are invented...
Trees prevent desertification and landslides also they give planet the oxygen we breathe, so let's make everything we can to preserve them for the good of all humankind.