What is the Von Thunen agricultural land use model?

The von Thunen model is a theory that requires: no outside influences, completely flat land in all directions, and extremely self-interested farmers.

It is a series of concentric rings, with the center being the city (usually represented as a black dot).

The first ring would be dairy and produce. The second ring would be wood. The third would be field crops, such as grains. The fourth would be the wilderness.