美国城市郊区化及对策对中国城市节约增长的启示

城市的空间发展中一直同时存在着向心集聚和离心扩散两个过程,郊区化是城市中心区离心扩散力量超过向心集聚力量的一种空间表现形式,能有效缓解大城市因规模扩大而带来的人口密集、交通拥挤等现象;但同时也会产生土地资源浪费、生态环境破坏、阶层分化隔离以及内城衰退等负面影响。美国的城市郊区化现象最为典型,在应对郊区化问题,如怎样有序的建设和管理以及处理好建设和保护的关系等方面积累了丰富的经验。然而,由于土地所有制和城市化阶段的不同,中国与西方发达国家的郊区化呈现出不同特点。中国目前正处于快速城市化时期,由于GDP导向下的城市空间跨越式发展使得一些大城市已出现郊区化现象,导致"外溢—回波"效应突出等问题。通过对中﹑美城市郊区化现象进行比较分析,同时借鉴美国在有效发挥郊区化作用和解决郊区化造成的问题方面的先进经验,并基于城市节约增长的视角,研究如何提高城市空间增长的效率,希望在先进理念、管理技术以及协调政府和市场职能作用方面对城市发展做出有效的把握和引导。

Suburbanization of the United States and Its Implications to the Urban Efficient Growth of China

There has been always centralizing and centrifugal forces during the urban spatial development processes.Suburbanization is a centrifugal process of urbanization that the centre centrifugal diffusion power is over the centripetal agglomeration.This phenomenon can not only effectively relieve the problems caused by urban expansion, such as high population density and traffic congestion, but also bring some negative effects, like a waste of land resources, the damage of ecological environment, the isolation of class differentiation and the recession of inner city.The United States is one of the most typical countries with suburbanization and has a wealth of experience in dealing with the problems caused by suburbanization, such as how to keep construction and management in good order and handle the relationship between construction and protection.However, because of the different land ownership and urbanization stages between China and western developed countries, the suburbanization phenomenon presents different characteristics.China is in the period of rapid urbanization.Due to the GDP-oriented during the great-leap-forward of urban spatial development, suburbanization has appeared in some well-developed cities, which cause "Spillover-Echo" problem, for example, people in new city cannot achieve on-site job, while the central city is too crowded.In this paper, the suburbanization in the United States and China are compared in details.And methods of enhancing the efficiency of urban spatial growth are proposed from the perspective of efficient growth to guide the city development in China.Learning from advanced experiences of the United States in both effectively making use of suburbanization function and solving the problems caused by suburbanization, and from the perspective of urban efficient growth, it is tried to study how to improve the efficiency of urban spatial growth, and make an effective guidance in growth idea, management technique and the coordinating of the government and the market function of urban development.