National Morale doesn't have influence on Supply

[Darksky]

At pag. 13, manual states: "National Morale changes affect different game factors, such as unit
cohesion maximum and cohesion recovery (reflecting the fact that military forces with high morale are generally
more combat-efficient), or production of supplies and assets"

I don't see any effects on supplies. Is the manual statement incorrect or am i missing something ?

Thanks