I want to pause before working on hammers, which are tricky, and examine whether or not the city growth model I've proposed would work to make a large city. After messing around with trying to get a screen shot off my Civilization IV (C4) game, I admit I don't seem to have the know-how ... so I'm going to steal this image below:
For the purpose of this post, we're going to ignore the growth of culture (which honestly would be different for D&D anyway). What, then, is the total food surrounding the village of Bibracte?
Well, I count 4 floodplains, 3 forests and 1 cow (on a grassland). The forests are all upon grasslands, so each offers (2) food (remember, the brackets are for C4 numbers, not translated for my D&D idea); the floodplains each offer (3) food; and the cows add a point to the grassland, making that worth (3). Bibracte itself produces (2) food. This is a total, in C4 terms, of (23) food.
Translating this into calories for D&D, the floodplains and cows offer 700 million calories each, while the forests and Bibracte offer 300 million calories each. This is a total of 4.7 billion calories, or enough for 23,500 persons.
Ah, but if the cows and the floodplains are improved, the use of the binary system greatly increases the food supply. Each floodplain counting as (4) in C4, once improved with a "farm," jumps to 1.5 billion calories. The cows jump to (5) in C4, or 3.1 billion calories. Even if the forests are left unimproved, this is 10.3 billion calories, or enough for 51,500 persons.
But of course, in order to work all eight tiles, Bibracte must have a population of (8) ... which in the system I'm employing, would mean a population of 127,500 - more than Bibracte can feed. As the reader can see, the system doesn't *quite* work out the way C4 does. More's the pity.
The breaking point comes when Bibracte has a population of (5), or 15,500, and can work all the floodplain tiles and the cows as well. At this point, Bibracte is overflowing with food ... it is only when it moves up to size (7) that food becomes an issue. There's also the matter of ways to improve the forest tiles, tearing them down, and (D&D assumes the civil service technology) irrigate farms on the grassland. Such farms would produce 700 million calories each, however ... only enough for an additional 4,500 people. There are other possible increases (biology) which would really bounce up the food production everywhere. It's questionable where you would want to limit your technological world - and isn't that a new concept in playing an end game in D&D?
C4 solves these issues by having the city expand its boundaries, so that it can take advantage of the floodplains on the other side of the river - and clearly the D&D comparison will need some kind of commensurate system that allows this. So there will need to be culture rules if cities are expected to get BIG.
There are other ways to think about the D&D's possible influence, however. Can you create "deer" by stocking the nearby woods like a game reserve? Food, as well, could simply shipped in from elsewhere, so that a city without the tiles could still get bigger and bigger by fostering colony cities that all have great abundances. The rules of C4 need not apply ... there are workarounds.
Okay, hammers next.