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The Von Thünen
Model

Understand how distance from market, transportation costs, and land rent shape agricultural land use in concentric zones around a central city.

AP Human Geography

What Is the Von Thünen Model?

In 1826, German economist Johann Heinrich von Thünen proposed a model to explain how agricultural land use organizes itself around a central marketplace. He asked a simple question: why do farmers grow different crops at different distances from the city?

Key Terms to Know

Market
The central city where all agricultural goods are sold. It is the single point of demand in the model.
Land Rent
The maximum price a farmer is willing to pay for land at a given distance. Higher-value crops command higher rents closer to market.
Transport Cost
The expense of moving goods to market. Perishable or heavy goods cost more to transport, so they must be grown closer to the city.

Model Assumptions

1
Isolated state: One city exists as the sole marketplace, surrounded by uniform farmland.
2
Isotropic plain: The land is perfectly flat with uniform soil quality and climate everywhere.
3
No external trade: Farmers only sell to the central city; no outside markets exist.
4
Rational farmers: Every farmer maximizes profit by choosing the crop that yields the highest land rent at their location.
5
Single transport mode: Goods travel directly to market (no highways, rivers, or railroads initially).

The Bid-Rent Formula

Von Thünen expressed land rent as a function of distance. The locational rent (or bid rent) for a crop is:

The Four Concentric Rings

M Ring 1 Dairy / Market Gardens Ring 2 Timber & Firewood Ring 3 Crop Farming Ring 4 Ranching / Livestock Distance (d)

Bid-Rent Curves Explained

Distance from Market (km) Land Rent (R) 0 2 4 6 Dairy Timber Grain Ranching

Why Each Ring Forms

Ring 1: Dairy
Perishable products spoil quickly. High transport cost per km means the bid-rent curve is steep: very profitable near market, but rent drops fast with distance.
Ring 2: Timber
Wood is heavy but durable. In the 1800s, it was essential for fuel and building. Its weight meant high transport costs, placing it close to the city.
Ring 3: Grain
Grain is light, non-perishable, and easy to ship. Lower transport cost per km gives a gentler bid-rent slope: it still earns positive rent far from market.
Ring 4: Ranching
Livestock can walk themselves to market. Extremely low transport cost: the bid-rent line is nearly flat, extending far from the city.

Von Thünen vs. Burgess Model

Von Thünen (1826) Burgess (1925)
Focus Agricultural land use Urban land use
Scale Regional (farms around a city) Intra-urban (zones within a city)
Driving Force Transport cost of farm goods Competition for access to CBD
Rings Contain Different crop types Different social/economic zones
Key Variable \( R = Y(P - C) - Y \cdot t \cdot d \) Rent gradient from CBD

How to Apply the Model

1
Identify the market center: locate the central city or point of demand.
2
List the competing crops and their market price \( P \), production cost \( C \), yield \( Y \), and transport rate \( t \).
3
Compute bid-rent lines using \( R = Y(P - C) - Y \cdot t \cdot d \). Each crop has a y-intercept of \( Y(P - C) \) and slope of \( -Y \cdot t \).
4
Plot and overlay: the crop with the highest \( R \) at each distance wins that zone. Ring boundaries occur at intersections.
5
Consider modifications: rivers, highways, or multiple cities shift the rings into elongated or asymmetric shapes.

Example 1: Computing Rent

A dairy farmer has: yield \( Y = 100 \text{ units/km}^2 \), market price \( P = \$5/\text{unit} \), production cost \( C = \$2/\text{unit} \), and a transport rate of \( t = \$0.50/\text{unit/km} \). What is the land rent at \( d = 3 \text{ km} \)?

Example 2: Ring Boundary

Two crops compete for land. Dairy: \( R_1 = 300 - 50d \). Grain: \( R_2 = 150 - 15d \). At what distance does the ring boundary occur?

Example 3: The River Effect

M River Rings stretch along waterway Normal concentric rings (no river)

Modern Applications

Von Thünen's model was built for 1826, but its logic still appears in the real world today:

Urban Fringe
Market gardens and truck farms cluster near major cities to supply fresh produce. Think of the farms surrounding cities in California's Central Valley.
Global Scale
Perishable flowers are air-freighted from nearby countries. Durable commodities like wheat are shipped from distant breadbaskets (U.S., Argentina, Australia).
Technology Shifts
Refrigeration and highways have widened the rings. Products that once needed to be near the city can now be grown farther away.

Common Mistakes

✕ Confusing with Burgess
Von Thünen is about agricultural zones around a city, not urban residential zones. Burgess is the urban concentric zone model.
✕ Forgetting Assumptions
The model assumes an isotropic plain. On the AP exam, if the question mentions hills, rivers, or multiple cities, the rings will not be perfect circles.
✕ Mixing Up Slope
A steeper bid-rent slope means higher transport cost. Dairy (perishable) is steep. Ranching (self-transporting) is flat. Don't reverse them.

Summary of Rings

Ring Land Use Transport Cost Bid-Rent Slope Distance
1 Dairy / Market Gardens Highest Steepest Closest
2 Timber / Forestry High Steep Near
3 Crop Farming (Grain) Moderate Gentle Far
4 Ranching / Livestock Lowest Flattest Farthest

Question 1 of 5

In Von Thünen's model, which factor is the primary determinant of which crop is grown at a given location?

Question 2 of 5

A crop has \( Y = 200 \), \( P = \$4 \), \( C = \$1 \), and \( t = \$0.30 \). What is the maximum distance from market at which this crop is profitable (where \( R = 0 \))?

Question 3 of 5

In the original Von Thünen model, Ring 2 is occupied by timber and forestry. Which best explains why timber is closer to the city than grain?

Question 4 of 5

If a navigable river extends northeast from the central city, how would the concentric rings change along that river?

Question 5 of 5

Which statement best distinguishes the Von Thünen model from the Burgess concentric zone model?