Hair is fibrous... Is there a good reason, why we don't recycle our own hair (and clothing, what have you) into paper-products? (rather than cutting down trees)?
The diameter of human hair is typically 100 microns (from 17 to 181 microns: https://hypertextbook.com/facts/1999/BrianLey.shtml ). The diameter of a cellulose fiber is about 10 microns ( https://en.wikipedia.org/wiki/Paper ), and a cellulose molecule is much smaller (up to about 10,000 glucose units long: https://en.wikipedia.org/wiki/Cellulose_fiber ).
While it should be possible to make a coarse papery product from hair, something is needed to make the hair fibers stick together without being sticky in the final product. Think how obnoxious it would be if you wash your hair, then dry it and it turns into cardboard!
Paper from cellulose fibers sticks together when it dries because there are so many hydroxyl groups on every cellulose molecule and fiber - no extra adhesive needed. It can be made quite thin - commercial paper is available as thin as 60 microns ( https://hypertextbook.com/facts/2001/JuliaSherlis.shtml ).
Hair, however, is long enough, and frequently curly enough, to be able to be woven into yarn or thread, and then into thick 2-dimensional products. The thickness of the yarn or thread gives the product more strength.