Türkiye'de kentsel kademelenmenin lojistik sektörü açısından değerlendirilmesi
Evaluation of urban hierarchy through logistics sector in Turkey
Yazar: ADEM SAKARYA
Danışman: PROF. DR. GÜLDEN ERKUT ; DOÇ. DR. YİĞİT EVREN
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Şehir ve Bölge Planlama Ana Bilim Dalı / Bölge Planlama Bilim Dalı
Derece: Yüksek Lisans, 2013
Konu: Şehircilik ve Bölge Planlama = Urban and Regional Planning

Özet:
Yerleşmelere yönelik kademelenme kuramı ekonomi ile coğrafyanın kesiştiği noktada ortaya çıkmaktadır. Bu kavram ile yerleşme merkezlerinin kademeleri ve etki alanları ifadelendirilmektedir.
Kademelenme kavramı ile ilgili ortaya konulan teoriler bu çalışmada neo klasik ve çağdaş dönem olmak üzere iki başlıkta ele alınmıştır. Daha dengeli bir kalkınmanın beklendiği neo klasik dönemde Christaller ve Lösch tarafından kademelenme teorileri ortaya konulmuştur. Bu teorilerin yanında aynı zamanda Zipf tarafından da kademelenmeye yönelik bir teori ortaya konulmuş ancak bu teori sadece nüfus değişkeninin ele alarak diğer teorilerden farklılaşmıştır. Çağdaş dönem teorileri ise Henderson ve Krugman- Fujita tarafından ortaya konulan teorilerdir. 
Bu teoriler ortaya konuldukları dönemlerin farklılaşması nedeni ile varsayım, kurgu ve yöntem açılarından farklılaşmaktadır. Bu farklılaşmaların en etkin örneği, neo klasik döneme ait teorilerde tüketici hareketleri belirleyici bir role sahipken çağdaş kuramlarda bu rol firmalara aktarılmıştır. Farklılaşmaların yanında bu teorilerin ortak yönleri de bulunmaktadır. Çalışmada incelenen tüm teorilerde merkez kademelenmesi ve etki alanları merkezde bulunan fonksiyonların/ hizmetlerin türüne ve yerleşmeler arası ilişkilere bağlı olarak değişmektedir. Ayrıca nüfusun alana dengeli dağıldığı (bazı teorilerde aynı etki alanı içerisinde nüfus dağılımı farklılıklar gösterebilmektedir), aynı kademe derecesindeki merkezlerin etki alan genişliği ve nüfusunun aynı olduğu varsayımı bu teorilerin ortak yönüdür.
Kademelenmeyi ortaya koyan önemli etkenlerden biri olan yerleşmeler arası ilişkiler genel olarak insan ve yük akımları ile sağlanmaktadır. Günümüzde yerleşmeler arası yük akımları ise en açık bir şekilde lojistik sektörü aracılığı ile gerçekleşmektedir. Lojistik firmaları yük akımlarının etkin bir şekilde gerçekleştirilmesi için dağıtım ağları oluşturmaktadır. Oluşturulan bu yapılarda merkez ve etki alanı bulunmaktadır. Bu durum dağıtım ağ yapılarının kademelenme teorileri ile paralel olmasına olanak sağlamaktadır.
Türkiye?de kademelenme kavramı ise yapılan bölgeleme çalışmaları sonucunda elde edilmiştir. Yerleşme Merkezlerinin Kademelenmesi çalışması, Plan Bölgelerin Tespiti çalışması ve Türkiye?de mevcut sistem olan Düzey 2 yapısı sahip oldukları bölge merkezi ve bu merkezin etki alanı ile kentsel kademelenmeyi oluşturmaktadır. 
Türkiye de kentsel kademelenme aynı zamanda ülkede faaliyet gösteren üçüncü parti lojistik firmaları dağıtım ağlarında da ortaya çıkmaktadır.
Bu bağlamda Türkiye?de mevcut durumda kentsel kademelenme ile ilgili Düzey 2 sistemi ve üçüncü parti lojistik firmalarının dağıtım ağı yapıları bulunmaktadır. Ancak bu yapıların kademelenme kuramlarına uygun olup olmadığı belirli değildir. 
Bu nedenle bu çalışmada Türkiye?de kentsel kademelenme ile ilgili olan mevcut kademelenme yapısı ve lojistik firmaları dağıtım ağlarının kademelenme teorileri bağlamında incelemeleri yapılmış ve incelemeler dâhilinde çalışmanın tezi olarak belirlenen mevcut kademelenme yapısı ile lojistik firmalarının dağıtım ağları arasındaki benzerlikler aranmıştır.
Çalışmada yöntem olarak Düzey 2 yapısı ile 5 üçüncü parti lojistik firmasının dağıtım haritaları, bölgelerin alan ve nüfus değerleri kapsamında değerlendirilmiştir. Değerlendirme 3 başlıkta yapılmıştır: Düzey 2 yapısı ile Türkiye?de kademelenme çalışmaları ile değerlendirilmesi, lojistik firmalarının dağıtım ağlarının kendi aralarında değerlendirilmesi ve Düzey 2 yapısının lojistik firmalarının dağıtım ağları ile değerlendirilmesi.
Çalışma sonucunda ise Düzey 2 yapısı ile lojistik firmalarının dağıtım ağları arasında kademelenme teorilerine göre bir benzerlik bulunmadığı ve dağıtım ağlarının Düzey 2 yapısına göre kademelenme teorilerine daha yakın bir yapıda olduğu görülmüştür.

Abstract:
The concept of settlement s hierarchy emerges when geography and economy intersect. With this concept the hierarchies of settlement?s centers and their tributary area are articulated.
In this study, theories for hierarchy have been taken into consideration in 2 terms: neo classic and contemporary. In neo classical term theories were introduced firstly by Walter Christaller via ?Central Place Theory?, and then Lösch studied about hierarchy by criticizing Christaller theory. Also there was Zipf?s Law in neo classical term, but it is different from Christaller and Lösch terms by considering population as just variable. In contemporary times there are two main theories. The first one is Henderson?s theory; it is like a bridge from neo classical to contemporary. After this theory Krugman and Fujita studied for hierarchy, this theory is absolutely appropriate to contemporary approach.
Emergence of these theories in two different period leads to their assumptions, methods and criteria to be different. An important difference of these theories is that neo classical approaches give a main role to consumer, but in contemporary approaches this main role is owned by firms/ companies. It is related to differences in economic situations of these terms, because in neo classical term economy was forced by government at large scale, in contemporary term the economy is based on market, forced by private sector. This difference affects the organization of settlements in different way, in neo classical term consumer choices, in contemporary term firm choices affects the space in different way.  
Besides these differences there are similarities between these theories. In the all theories, examined in this study, the hierarchy of centers and tributary area are based on types of functions that locate at these centers and relations between settlements. Also assumption of balanced population distribution (inside a region the population distribution does not have to be equal) between regions (center + tributary are) and centers at the same rank have same tributary area and same population are another common dimensions of these theories.
Relations between settlements, an important factor of hierarchy, are provided by human and freight flow today. Especially, because of technological developments, freight flow is more important than human flow, generally people prefer freight coming themselves, not going to freight. The freight flow can be seen clearly in logistic sector. This flow is between countries, regions, cities and settlements by logistic firms. These firms, third party logistic firms, have aim to maximize their profit, so they have effective distribution system both national and international. This distribution system generally has production point where freight flow starts, distribution centers and consumer where freight flow finishes.  The distribution center is a center of a region consisting of consumers locating at tributary area of this center. This scheme is look like hierarchy theories with this center and tributary area.
Logistic has similarities with urban hierarchy as mentioned above, but what logistic is. This question is answered in this study with multi titles. Logistic was emerged from freight flow. Firstly it had been used in military by meaning effective, strategic transportation of freight and soldiers. By technologic developments, logistic was introduced in business in 1970s and 1980s. Logistic provides firms to have elasticity; they get material when they need by logistic. Especially, just in time production system has triggered logistic development. 
In logistic there are many service like transportation, storage, handling, management etc. The most important service is transportation, it consists 60% of all logistic service costs. Transportation is provided by many different modes; roads, railway, sea way, airway and multi modal. This service with these modes generates the relations between settlements.
These logistic services can be provided by producers, but with technological development they are provided by logistic firms (third party logistic) as mentioned above. It helps producers be focus on their business, not on logistic services.   
Hierarchy concept in Turkey has emerged from zoning studies, and the goal of all was to have regions nationally. Studies like Hierarch of Settlement Centers (Yerleşme Merkezlerinin Kademelenmesi), Determination of Plan Regions (Plan Bölgelerin Tespiti) and Nuts 2 system, valid now in Turkey, constitute urban hierarch by having region center and its tributary area. The last productions of these studies look like each other as scheme, but their backgrounds are not same.  Hierarch of Settlements Centers study was done based on Christaller theory, with surveys in 1982. It gave importance to functions of centers and relationship between settlements. Determination of Plan Regions study was done by government without clear analytical background. The Nuts 2 system is a model of European Union for to evaluate all European regions in same way with regional statistics. Turkey is a candidate country for EU, and the Nuts 2 system was accepted in 2002 and applied.
These all studies were done by government, but there are urban hierarchy systems of private sector too.  One of these is logistic. In Turkey there are third party logistic firms and some of them have distribution system like urban hierarchy scheme. In this study, logistic sector was analyzed to understand the third party logistic firms? distribution system. Logistic in Turkey was analyzed in two main title; international and national, but more importance has been given to national system. Internationally, Turkey is 27 at logistic performance index, prepared by World Bank. When it is compared with international economic rank of Turkey, 17, it is seen that Turkey is not at enough stage for logistic. International logistic includes import and export. Turkey has different leader partners in import and export, so transportation modes are different between import and export.  Nationally, logistic sector has continues increasing trend in gross domestic per capita. In Turkey, 93% of total logistic transportation is done via roads. Railways, seaway and airway are not used effectively. Third party logistic firms generally use roads to for transportation and that compose urban hierarchy via relationship between settlements.  
In this context, for urban hierarchy at current situation, there are Nuts2 system and third party logistic firms? distribution maps in Turkey.  Therefore, hypothesis of the study was defined as there is similarity between Nuts 2 system and logistic firms? distribution system.  
To test this hypothesis firstly Hierarch of Settlement Centers study, Determination of Plan Regions study and Nuts 2 system are mapped. Then, semi- structured interview was made with 5 third party logistic firms, they were selected from Capital 500 list, and their distribution systems were mapped via GIS. 
These maps were analyzed in two stages; firstly area and population of regions were correlated, and correlation coefficient was calculated, because, as mentioned before, in all hierarchy theories it is accepted that population density is same at every settlement. That means there is a positive and strong correlation between area and population (the correlation coefficient is equal to 1). With first stage, suitability of these maps to hierarchy theories was examined, and maps are compared via correlation coefficient.  Differences between coefficients were analyzed at second stage via population density maps.
About correlation coefficient Hierarch of Settlement Centers study has the most closed value (0, 8) to hierarchy theories. In Determination of Plan Regions study there is positive relation (0, 3) between area and population, but it is not strong as Hierarch of Settlement Centers study. Nuts 2 system has negative coefficient (-0, 1), it means that it is not suitable to hierarchy theories.
Correlation coefficient of logistic firms? distribution systems are generally between positive 0, 4- 0, 5. There is positive relationship, but it is not strong.
These coefficients? differences generate from differences between maps within the context of regions? borders and centers. Especially, when Nuts 2 system and firms? distribution maps are compared, it can be seen that Nuts 2 system approximately divides Turkey into equal area to provide public services all inhabitants equally, but in firms? distribution system  they try to maximize their profit, so they position more regions at place where more consumer locate.
With these conclusions, it was found that there is no similarity between Nuts 2 system and third party logistic firms? distribution system in Turkey within the context of hierarchy theories.
There are suggestions at the end of thesis for both hierarchy and logistic in Turkey. For hierarchy the Nuts 2 system should be reviewed and for new hierarchy system in Turkey relations between settlements must be analyzed as done in 1982, Hierarch of Settlement Centers study. For logistic, freight map of Turkey should be prepared according to relations of settlements. To constitute this map information of which goods at what quantity and from where to where are sent is necessary. With this it will be understood that which goods locate where, and this helps logistic firms to organize their distribution system effectively.