大都市空间扩展的廊道效应与景观结构优化*──以北京市区为例

由于存在城市中心梯度场和廊道效应梯度场,在单纯经济利益趋动下,城市本质上存在摊大饼倾向,这将严重破坏城市合理景观结构与生态平衡.文中运用廊道效应原理,研究人工廊道与自然廊道相互作用过程,结合北京中心市区不同时期空间扩展格局,分析城市景观8个方位廊道的扩展量、扩展速度及变化趋势,提出将自然廊道体系纳入北京大都市区规划,形成人工廊道与自然廊道相间分布的星状分散集团式景观格局,以有效阻止建成区摊大饼过程.

THE CORRIDOR EFFECTS AND OPTIMIZATION OF LANDSCAPE STRUCTURE IN A METROPOLITAN AREA--A CASE STUDY ON BEIJING

This paper is concerned with two types of urban corridors, artifitial corridors and natural corridors. The concept of corridor effect is examined in a metropolitan landscape structure. The analysis is undertaken by using a distance decay curve which is based on an idea concerning the concept of "corridor benefit". The line of demarcation between artificial corridor and natural corridor is the synthetic benefit point from the thoery analysis. This study suggests that there are two synthetic benefit points on the curves of distance decay for the existence of a natural corridor between two artifitial corridors. In particular, it is necessary to avoid a high density of artificial corridors and to improve social and economic benefits in natural corridors. The spatial growth of 8 corricors is examined in the central area of Beijing. This inner city study attempts to replicate several findings of green area and water system as a framework aroud and through the center of the city combined with the east, the west, the south, the north and the eight directions of natural corridor effects in traditional chinese city planning. The ideas of human and nature in perfect harmony were used in the metropolitan landscape planning. The landscape structure of Beijing should change from a multiple form to a star shaped from in order to avoid the massive growth of the built up area.