THUNEN, JOHANN HEINRICH VON

born June 24, 1783, Jever, Oldenburg died Sept. 22, 1850, Tellow, Mecklenburg German agriculturalist best known for his work on the relationship of the costs of commodity transportation to the location of production. In 1810 Thnen began gathering data for the book for which he is remembered, Der isolierte Staat (1826; The Isolated State). In this work he imagined an isolated city, set in the middle of a level and uniformly fertile plain without navigable waterways and bounded by a wilderness. In this model he showed concentric zones of agricultural production. Heavy products, in proportion to value, and perishables would be produced close to the town; lighter and durable goods, on the periphery. As transport costs to the city increased with distance, the returns to the land would diminish until, at a certain distance, land rent would become zero. Moreover, methods of cultivation would varywith land cultivated more intensively near the city, where it was more valuable. Subsequent writers have often built upon Thnen's model.