Paper = trees?
Paper had been invented in China by the second century AD and was
introduced to Europe in medieval times. Originally it was invariably
made from cotton and linen rags, which is a great irony when you consider
that the debate about the benefits of recycling paper seems to always
ignore the fact that paper was the original recycled product!

Foudrinier papermaking machine, c. 1840 |
In 1810 a pound weight of rags commanded a street price of 3d - worth
as much as two hours work for a labourer - and the price rose steadily
over the following few decades as demand for paper outstripped the
available supply of rags.
In part, the shortage was caused by introduction of mechanical paper
making, invented by the Foudrinier brothers about 1800. More importantly,
the steady rise in public literacy stimulated demand for printed products
of every kind. It was this demand which drove Victorian entrepreneurs
to search for a cheaper and more plentiful raw material to replace
the now expensive rags.