Nope, actually it was a multi-purpose conspiracy which also was intended to weaken
some militaries power, because the fibers of hemp were used to produce ropes and clothes for military.
Beside this, industrials feared about losses in their turn overs due to the fact,
paper made from wood needs wood and more chemicals to get produced in compare to paper made from hemp.
Paper made from hemp is factually better than paper made from wood.
Same is valid for fabrics made out of cotton and the cotton agriculture was a huge economic field.
You can read the whole story, if you search for Jack Herers Book and read Chapter 4.
If they didn't changed it, it's available online.