Rules Tinkerer and Freelance Writer
1: I -specified- that it would be dependent on the diet, soil quality, availability of water, and loss of crop to pest and pestilence... and then talked a bunch about river valleys where 1 acre would be more than enough particularly when you include growing seasons. So you turned around and just went "European Diet"... What the heck, Ixal? Also there is no "European Diet". Diet was -massively- dependent on class, region, season, and political limitation.1 Acres for a family of 4 sounds rather on the low side assuming a European diet. If anything goes wrong they will instantly starve and even in the normal years won't have that much of a buffer.
One thing to remember though that long lasting sieges only worked because cities were supplied from the outside which also happened at Candia/Heraklion. They didn't have protected farms within the walls which could supply their population. No city has.
Also because without refrigeration you can't keep long lasting supply anyway.
Donut cities do not really work as the demand for fields vastly outstrips the ability of cities to encircle them. Protecting every field with walls is possible but very expensive. And without defenders a wall is useless.
You ignored pretty much everything I was saying in order to make it narrowly Eurocentric. Why?
2: Yes. That's why I specified that the supplies from the -French- and the -Smugglers- combined with what they grew in the city itself (Mostly in private gardens to supplement the bulk coming in as grain). I also specified that it was the longest siege in history and wasn't really representative of your typical siege which lasted a year or two, for which a given city would likely have enough long-term goods inside the city. 'Cause you didn't need refrigeration to keep grain and flour shelf-stable for years on end. You throw flour in a sealed barrel in a dark room under the castle and it'll last 2-3 years unless something happens to break the seal.
You ignored pretty much everything I said on the topic in order to try and make a point that I already made. Why?
3: Of course donut cities don't really work. There's a reason we never bothered with them. However we don't live in a magical fantasy world where constant violence and monster attacks target farms, and so don't need to do ridiculous things like having massive curtain walls with towers and armed guards.
That said, the needs of the populace are always going to be dependent on the same things I said, before. In a particularly warm and wet river delta it would be possible to create a donut city, for a long while... and when the population starts outstripping the inner fields, make outer fields surrounded by a new ring of "Donut City" creating a series of "Dyson Towns" surrounding the harvest. And because of the square cube law, each ring growing outward would both produce exponentially more food and require exponentially more people and housing to fully surround it. So you'd wind up with an ever thinning outer ring of people with either narrower and narrower fields between the concentric rings of your donut city, OR you'd have fields of similar size and just SO MUCH EXCESS that you can ship away.
In any case: It was a suggestion of a way to protect against fantastical threats and has very little impact on real world city-planning or metropolitan design.
Really weird that you quoted my post, ignored much of what it said, and then tried to correct me on it all...