But they are producing a resource that you can extract from the tax
You mean the special resource?
What do you mean by "extract from the tax"? Do you mean the
bonus?
Assume a 5% bonus of gold, wood, iron or stone - How does population of the colony make a difference in this bonus?
If the colony has 10 population there is a 5% bonus. If the colony has 1 million population, there is a 5% bonus. The
colony does not actually produce resources on it's own, but (as I understand it) provides a bonus to production in the
PROVINCES. How does population in the colony make any difference?