Thanks for your input.

I'm trying to get a handle on how the three main wealth creation/allocation avenues interact, and what results their interactions have with regard to city populations and the flow of history. The three avenues I'm referring to here are raw production (agriculture, mining, forestry, fishing, etc.), manufacturing (metalworking, textiles, brewing, crafts, etc.) and trade. To use your words, production would be fairly static, manufacturing would be somewhat more dynamic, and trade would be the most dynamic of the three. Each layer is interrelated with the other two.

I'd guess that what you're saying is that the development of guilds and their associated industries within each city are more important than the trade that occurs with other cities. I imagine that manufacturing industries would generally spring up in close proximity to the raw materials they require; textile guilds near supplies of wool or flax for instance.

I'm also trying to figure out how to decide where manufacturing centers arise, since they're at least as important as centers of trade. Perhaps this whole problem could be divided into a three layer system as I mentioned above: production arranged semi-randomly based on biome, manufacturing appearing initially near raw materials, and trade allowing manufacturing centers to compete. I'm open to suggestions on how to model the growth or failure of guilds and manufacturing, especially concerning how they relate to trade.

When I mentioned fine timber, I was actually trying to draw a distinction between the kind of wood that would be used for firewood or simple construction versus the great beams needed for the roof of a cathedral or the keel or mast of a ship. This might be important in a province analogous to Holland, with a large shipbuilding industry and insufficient forests to supply it.

I don't need to simulate everything perfectly; I just want to produce something that's not completely unrealistic.

To that end, I've divided goods into a number of categories. Goods like food locally depress the demand for similar goods, and low value goods like bricks are unlikely to be traded. The categories are food (cheese, fish, fruit, grain, livestock, salt), intoxicants (beer, coffee, opium, tea, tobacco, wine), construction materials (bricks, stone, wood, fine stone like marble, fine timber for ships), textiles (cotton, flax, furs, silk, wool), metal goods (armor, tools, weapons), and luxuries (books, dyes, glass, incense, jewelry, perfume, porcelain, spices).

Obviously, things can always be more finely divided or grouped differently and I'm open to suggestions. But I'm mainly interested in continuing the discussion of what leads to the growth of city populations, industries, and trade.

Quote Originally Posted by Al. I. Cuza
In addition to this fine explanation: It depends on how long you intend to play. What settlements produce won't change overnight.
The time scale could extend out to multiple lifetimes, though probably not more than 200 years.