FIGURE 12.1 The Isolated State, von Thünen’s model: the black dot represents a city; 1 (white) dairy and market gardening; 2 (green) forest for fuel; 3 (yellow) grains and field crops; 4 (red) ranching. The area beyond this represents wilderness where agriculture is not profitable. (Image courtesy of Matthew Skjonsberg, after von Thünen.)