Study On The Coupling Relations Between Urban Scale And Intensive Land Use

In the21st century, with the advance of industrialization and urbanization, scale-expansion phenomenon of cities in China becomes more and more obvious, while the number of large cities and even mega-cities increases. Faced with national condition of more people with less land, there is an increasingly urgent requirement of changing land use from extensive to intensive utilization, especially intensive urban land use, which is an important lever of promoting scientific development and changing developing patterns. Intensive urban land use has become the inevitable demand of sustainable development, as well as the improvements needed for rational urban structure and prevention of urban sprawl. Urban scale and intensive land use are respectively the results of urban extension and internal land excavation. Important theoretical and practical significance can be recognized in studying the coupling relation between them in the current context has.Based on the principles of factor substitution and agglomeration, the study analyzes the theoretical relationship between urban scale and the intensive use of land: under static conditions, intensive urban land use drives relatively cheaper non-land elements including capital, labor and technology substituting land element within the existing urban area, which means more non-elements input in per unit area, while higher development intensity replaces horizontal expansion of the urban scale in satisfying the demand for land.In this mechanism, intensive urban land use tends to have a negative effect on urban scale; under static conditions, urban land intensive use will cause economic elements gathering in a single block, urban district or the city overall level. External economies of scale will induce agglomeration effect, which draws and accumulates more economic elements, promoting the inner industrial upgrading, pushing the lateral relocation of the weak industries, and thereby expanding the horizontal scale of the city.The study builds a structural equation model of urban scale and intensive land use. Firstly various indicators which are frequently used and whose data are available are selected to analyze the multi-relationships by principal component analysis method. The cumulative load value of the first10principal components is more than85%, so indicators with high load value in each of the10principals are chosen. Those indicators are selected to evaluate the intensive land use of each large city, also chosen with urban scale as variables in SEM. An initial model of urban scale and intensive use of land with those chosen indicators is built, and then repeat the model fitting, assessment and modification procedures to obtain the optimal structural model of the relationship between urban scale and intensive land use.According to the SEM’s output, the paper analyzes the parameters and principles of each path in the model, and the overall coupling relation between urban scale and intensive land use. The findings are consistent with theoretical assumptions, that there are both significant and direct "negative"-coupling relations as well as significant indirect "positive"-coupling relations between urban scale and intensive land use. The overall effect is positive, which means that under the current condition of development, the improvement of land intensity will facilitate the further expansion of urban scale in China’s large cities.So, the current policies for urban development need to be aware that in the current circumstances, an more intensive land use will inevitably cause a larger urban scale, so certain space still should be provided for the big cities to improve its land use conditon. On the other hand, the larger urban scale seems to be companied by a relatively larger construction land area per capita. So it is more important to realize that there is an urgent need to make more use of internal urban land, intensive land use condition of large cities in China should be further improved.