An Application of Central Place Theory: Merangin District, Sumatra

Map from here.  Note Jambi Province 

This week I'm down in Bangko, the capital of Merangin district for some research work.  Merangin is just east of Kerinci district, where I live.  It's one of the districts of Jambi province, which you can see from the map to the left.  One of the things I'm interested in is the long- and mid-range planning documents from the regional planning authority (BAPPEDA).  These documents have all sorts of information about the socio-economic aspects of the district, as well as information concerning the policy orientation of the government (i.e. what are the problems facing the district and what are the steps the government needs to take to address the problem).  Knowing these aspects of the district, which has about 20% of its territory covered by Kerinci Seblat National Park, helps me to understand the roots and context of current and potential conflicts between the people and institutions in the district and the park.  And, as a geographer, I like to look at the plans because they have all sorts of cool maps.


One section of the district's long-term (15 year) development plan describes the hierarchy of cities in the district.  As I read through the description, I was reminded of one of the classic models of geography: Walter Christaller's Central Place Theory.

Central Place Theory

Awesome GIF from Wikipedia

Walter Christaller was a German geographer active from the 1920s until around the 1950s(1).  He is most known for his Central Place Theory, which is a staple of introductory geography textbooks.  Central place theory is a model that attempts to describe (and predict) where and why cities of different sizes will be found on the landscape, and how they relate to one another.  The model has some basic assumptions, like most simple geographic models (recall my explanation of Von Thunen's model in a previous post).  It assumes that the world is an isotropic plain and that resources and people are distributed equally.  All people make rational decisions, and they will go to the closest place offering the goods or services they need.  Since the landscape is an isotropic plane, they can take the shortest distance to their destination.  

Christaller divided goods and services into different categories.  Simple or lower order services include things like markets and gas station and can be found in a lot of locations.  More specialized  or higher order services like universities are fewer and farther between.  Directly related to the order of service are two concepts which Christaller pioneered: threshold and range.  Threshold refers to the minimum population required to support a certain type of service.  Think about a minimarket, for instance.  They are everywhere because it doesn't take too many customers to keep a minimarket in business.  The threshold is low.  Range, on the other hand, is the maximum distance people are willing to travel to avail themselves of a service.  Returning to our minimarket example, you're probably not willing to travel too far to find a Circle K.  So the range is low as well.  However, there are some services, like movie theaters, ice skating rinks, Ikeas, etc, that you are willing to travel farther to access.  At the same time, these services need a lot more folks to keep them in business.  So the threshold and range are both high.  Cities or towns that provide only simple services are low order settlements, whereas larger cities that offer a more comprehensive range of services are high order settlements.  

Diagram from Hofstra University's excellent website.

Christaller's basic idea is that in a given region, there will only be a few high-order settlements, but there will be lots of lower-order ones.  What's more, settlements will be spaced equidistant from one another, and higher-order settlements will be surrounding by a number of lower order settlements, which rely on the bigger city for rarer goods and services.  There are several levels in the hierarchy, from huge metropolises on down to regional cities, towns, villages and hamlets.  You can see a diagram of the arrangement of the various classes of settlement to the right.  Each of the different types of settlement has a different market area; large (higher order) cities have bigger market areas.  Remember that people will go to the place closest to them offering the desired good or service; this accounts for the regular spacing (2).  In addition to this market principle (known in the theory as the k-3 principle) Christaller also described transportation (k-4) and administrative (k-7) functions, but we don't need to go into those here.  

Christaller used Central Place Theory in his role as a planner for several evil regimes in Europe.  Since the introduction of his theory, scholars in geography have attempted to apply it to other instances as well in order to prove or disprove its merits.  It has also influenced the discipline of regional planning, as we'll see below.  

Central Place and Merangin District?

The capital of Merangin district is Bangko.  Bangko is surrounded by a number of smaller towns, which in turn are surrounded by villages.  The district is mainly agricultural but there is some industry as well (most of which centers on the processing of agricultural commodities).  As you can imagine, there is a natural ranking of services in the settlements of various size in Merangin.  For instance, every village has a place to buy instant noodles or cell-phone credit.  Larger towns act as transportation hubs, and the capital city functions as an administrative, management, and financial center.  That's all common sense, and in my mind Christaller doesn't deserve much credit for describing the natural way that markets work.  

What is remarkable, though, is that way that the planners have adapted Christaller's ideas in their development planning.  Within Merangin district there are 9 subdistricts (kecamatans).  One of the problems the planners are hoping to solve, though, is an imbalance in the level of development and economic opportunities between subdistricts.  They are also hoping to develop a district-wide system where each subdistrict develops according to the resources located in the subdistrict; for instance, the subdistrict of Jangkat has lots of land with good soil and not many people, so the planners are hoping to increase the amount of palm oil and rubber plantations there.  Likewise, each subdistrict should be part of a larger system with the district capital (Bangko) at the top.  

In order to facilitate this vision, the planners have created a hierarchy much like Christaller's.  In the district system Bangko, the capital, is referred to as an Order 1 (Orde 1) center.  It is a center of transportation, located on the main overland route to the provincial capital at Jambi as well as the roads to other districts (Sarolangun, Bungo, and Kerinci).  It has the most complete economic facilities and is also a center of banking, trade, management, and communication.  In the words of the planning document, it is the Center of Regional Activities (Pusat Kegiatan Wilayah, PKW).  Beneath Bangko in Kota Rantau Panjang, the capital of Tabir subdistrict.  Rantau Panjang is an Order 2 (Orde 2) town in the district framework and is a center of local activities (Pusat Kegiatan Lokal, PKL).  It has good infrastructure and provides subregional services.  Then at Order 3 (Orde 3) we have Sungai Manau and Pamenang.  Both of these towns are about equidistant from Bangko.  In the planning framework they provide lower-order services to their hinterlands and are supposed to spur development in the areas immediately around them.  Lastly we find Muara Siau, a smaller town at Order 4 (Orde 4).  The quality of infrastructure is lower, and it provides still lower-order services to the mainly agricultural hinterlands surrounding it.

The planners of Merangin district use this framework to help plan what sorts of projects need to be developed in various places.  For example, they are working to develop higher-order transport facilities in the district capital, but in the lower-order centers they plan smaller-scale projects aimed at improving specific aspects of the economy in those places.  This helps them to distribute resources, like money and equipment, in a more efficient manner aimed at developing the district as a whole.  You can see the results in the map below, which divides the entire district into development zones, each with its own set of projects and targets.  I've labeled the various centers along with their order.  The spatial arrangement somewhat mirrors that predicted by Christaller, but more important, at least to me, is the function of the various centers.

We can see from this example that geographic models not only help us understand spatial distribution and organization from a theoretical perspective, but they are also important tools in policy making.  Central Place Theory has clearly influenced the planners in Merangin district and has helped them to formulate a development plan that specifically addresses the strengths and weaknesses of each subdistrict.

Notes

(1)  Christaller was not only a NAZI, but a COMMUNIST as well.  I faced something of a moral dilemma when writing this post....I am still somewhat ambivalent about describing a theory that was used primarily for organizing hostile occupations and oppression

(2)  Christaller adopted hexagons rather than circles because hexagons nest together perfectly without any overlap or gaps, unlike circles.

(3)  I am basing this on the 2006 long-range plan; in 2008-9 the authorities experienced a frenzy of new district creation, and now there are 26 kecamatans.

A Geographic Solution to Kerinci's Agricultural Woes: The Distance to Market Problem

Picture of Von Thunen from Wikipedia

As I've mentioned in previous post, the Kerinci Valley is one of Indonesia's prime agricultural regions.  Because of its situation, it's also quite far from large market/export centers.  The port of Padang is about 7 hours to the north, and Jambi city is 12 hours through the mountains.  Thus Kerinci farmers face a significant obstacle to getting their goods to market.  In this post I'll review one key geographic model about the relationship between market distance and crop choices and then propose a novel solution to the distance to market dilemma faced by Kerinci's farmers.

Von Thűnen's Rings

Geographers have long been interested in the relationship between distance to market and agricultural production.  One of the earliest and best known models was developed by Johann Heinrich von Thűnen, a German land owner and geographer active in the early 19th century.  Von Thűnenwas interested in why farmers decide to grow certain crops in certain places.  His model, known vernacularly as "Von Thűnen's Rings", was published in his "Isolated State" in 1826.  Von Thunen argued that there are three key variables that affect crop choices: land rent (or production costs), market price, and transport costs.  Von Thűnen's Isolated State has several conditions:

• There is a centrally located market town...
• The land is an isotropic plane, meaning there is no topographical variation
• Farmers are rational decision makers
• Farmers are able to transport goods directly to the market. 

According to Von Thűnen's calculations, there is a pretty significant distance decay for agricultural products.  This causes the emergence of several discrete zones of production radiating out from the central market town.  Since farmers on the isotropic plane don't need to worry about roads, these zones take the form of concentric rings, as shown in the diagram.  Von Thunen's model is pretty simple and basic (and contrived), but it is instructive.  Let's take a look at an example.  Below I have some hypothetical production and market data.  We can use this to figure out how profitable each crop will be in various locations, which is all the "rational" farmer needs to know to make his/her decision. 


                                     Milk      Forest   Extensive Field Crops   Ranching      
Market Price                 180         140                      105                     60      
Cost of Production         60           45                        32                      20      
Transport Cost/km         25           15                         8                         4   

Based on this data we can make some simple calculations.  Milk goes bad fast and it has to be refrigerated or brought to market quickly, which contributes to its costs of production.  Ranching, on the other hand, costs much less because the cows, lambs, goats, etc that you raise can transport themselves to market by walking.  Let's calculate the productivity per distance.  Below you can see the simple spreadsheet I made for profitability.  At each distance I highlighted the most profitable crop in green.  As you can see, Up to somewhere between 2-3 km, milk is the most profitable, so that's what farmers will produce.  But as you move farther away from the market the crop choice changed, until finally farmers choose ranching!

Like I mentioned, this is a very basic model, and like all models it doesn't exactly demonstrate reality.  But geographers through the years have demonstrated several examples that loosely correspond to Von Thűnen's rings.  To the left you can see one famous example from Uruguay.  But it's important to remember that Von Thűnen's model is on an isotropic plane and so topography doesn't matter and all goods are transported in the same way.  The real world doesn't work like that, though.  In the real world there are natural obstacles, like mountains, as well as transportation options that lower the cost of moving goods to market (think of trains and rivers).  So we can modify the Von Thűnen model by adding a river.  Look at the diagram below (from the Human Geography I use when I teach introductory geography).  As you can see, the river changes the picture significantly.

When we start to make the model more realistic, it becomes much more useful.  Have a look at the graphic I lifted from Hofstra (who lifted it from a couple of well-known geographers).  On the left you see the very basic model applied to the US in the 19th century.  It's not very accurate.  However the second model adds climate factors, which are really important in agricultural decision making.  With the addition of this consideration, the model corresponds much more closely to actual conditions.

AMBROSIA!!!

So as we've seen, one strategy for dealing with distance to market is to change crop choices.  There is another strategy, though: add value.  Many agricultural commodities are time-sensitive; that is,  they will go bad if they aren't consumed quickly enough.  This was a big problem in the frontier grain producing areas of the US in the 18th and 19th century, before the increase in western urban areas and the advent of railway and refrigeration technology.  So farmers figured out that in order to make a living, they needed to add value to the grain they produced.  The solution was simple: distillation.  Farmers on the frontier, far from markets, started making whiskey from grain since whiskey keeps for a long time.  It's also much more valuable per unit volume, and so the transport costs decrease for whiskey.

Cartoon from here.

These pioneering whiskeymen might have been forgotten to the world if it weren't for a tax levied on corn in the form of hooch levied by the fledgling US government in the 1790s.  The Pennsylvania distillers refused to pay the tax and even took up arms against the federal government.  Then president George Washington raised an army and marched to Western Pennsylvania, but by the time he arrived the rebels had already dispersed.  The "Whiskey Rebellion" ended up without a shot being fired, but it did demonstrate the willingness of the new nation's government to enforce its laws.  It also provided an outstanding example for generations of geographers to use when discussing distance to markets.   

Kerinci's Potatoes...

Picture from here

But what does all this have to do with the Kerinci valley (1)?  Well, Kerinci is well-known for its potatoes (for a number of reasons).  The climate here is just about perfect for raising the tubers, as the temperature is cool enough (68 degrees) for "tuberization" to happen.  The poorly-patrolled slopes of the national park have also proven to be an excellent free-land resource for farmers.  But there are a couple of problems with Kerinci's potatoes.  The first problem stems from the amount of chemicals farmers use in producing potatoes.  They use chemical fertilizers, insecticides, herbicides, and all sorts of other nasty synthetic things, which leave a residue on the potato.  Picky consumers (and regulatory bodies of non-kleptocratic governments) are very hesitant to buy potatoes that mgith subtract years from their lives.  The second is that, as I mentioned previously, the valley is pretty isolated.  So there are high costs incurred in transporting the potatoes to market.  In addition, Indonesia's potato farmers in general have been having problems as of late because they can't compete with cheaper imports.  The first problem has yet to be solved, but there has emerged here a cottage industry centered on potato processing.  The result is dodol, a tasty potato candy.

Picture from here

But you can only make so much dodol, and it doesn't have the widespread appeal of some other products, like alcohol or pornography.  Thus taking a page from the book of the frontier distillers, I propose that Kerinci's potato farmers form a co-op to distill and market vodka.  As everyone knows, true vodka comes from potatos.  Vodka production would provide the Kerinci valley with a flagship product that would really put this place on the map.  It's not too hard to make; the Russians have been doing it for over a thousand years, and they couldn't even win the Cold War.  It's also easy to transport vodka; the co-op could contract with Pertamina (the state-owned gas company) to use the trucks that bring gasoline to the valley to transport vodka out of the valley.  And we're sitting on the huge market of Southeast Asia, which, including children (the largest growth market), numbers hundreds of millions of people. I've already got a name picked out: Absolut Kincai!

Notes

1)  If you already know where I'm going with this, give yourself 10 bonus points.