Wood is made of celuloce and lignine. For paper, you use only the celulose, so it's necesary to remove the lignine. So there is a lot of lignine that is industrial waste.

(I guess it's burned as fuel.) (A few years ago, a YC funded company proposed to use lignine insted of asfalt in some roads. No idea what happened to them.)

Or it could lead to more being planted. Stora Enso say they are using FSA certified wood - and yes I am sure there are lots of scams in this 'certification', but I do see a positive possibility here.