Have a growth per production ?

[guillaume-alvarez]

Let say each tile produces some quantity of goods: FOOD (oat, wheat, beef, etc.), MATERIAL (stone, iron, wood, flax, etc.), LUXURY (gold, silver, wine, etc.) depending on its type.

The quantity produced is increased at each technology and policy. For instance GRASSLAND produces FOOD, when discovering oat (positively affected by GRASSLAND and PLAIN) each GRASSLAND tile produces +1 FOOD.

The quantity produced for all goods is summed at the power source (i.e. village/city): this is the power the city can sustain. Every turn the current power slowly progresses toward the sustainable power (be it positive or negative).

It means having lot of tiles allows to support a bigger city.

In case of tribute, a part of luxury (and only luxury) is given to the overlord.
In case of revolt the current power in the original city is not modified, but will progressively reduce as it lost tiles.
When creating an army, it is sustained from the MATERIAL part, that thus cannot sustain the city itself.