[C3C] Question on "Doubles City Growth Rate" for Improvements and Wonders.

[B-29_Bomber]

Does this stack for multiple improvements? For instance, let's say I build a granary (which has this feature) and a second building (also with this feature), will the city double it's growth rate twice?

 

[justanick]

I very much suspect that regaining half of the food required for growth applies only once per turn. So that effect does not stack with itself.

But there is a different effect from the wonder of long life. It means the each time a city growth, you gain 2 population points instead of one.