ECOLOGICAL ENERGETICS, HIERARCHY, AND URBAN FORM - A SYSTEM MODELING APPROACH TO THE EVOLUTION OF URBAN ZONATION

Cities are hierarchical centers of consumption and have had sharp puls es of growth and decline over history. Viewing regional development fr om an energy perspective is appealing in its analogy to natural system s, though the theory itself as applied to social systems remains undev eloped. The evolutionary changes of an urban system are strongly deter mined by exogenous energetic inputs and internally self-organized beha viors. Energy from life-support and production systems transformed and is converged spatially to urban centers. The energy-systems language method has kinetic and energetic definitions to represent open thermod ynamics and the equations for simulation. This method is applied to st udy the evolution of urban ecosystems. Ideas of systems ecology and en ergetic hierarchy emerging from general system theory are adapted to f ormulate a macro evolutionary model of urban zonal systems. Five conse cutive zones are proposed to represent Taipei metropolis: undeveloped; agricultural; residential; industrial; and urban. Each zone includes variables of area, asset, and population, and pathways interconnecting system components. Left-right positions of each zone indicate places in energy hierarchy with power circuits from left to right linking dif ferent zones, and control circuits from right to left. A model of urba n zonation formulated as a set of differential equations is developed. The model is run to assess the evolution of urban zones in relation t o energetic flows. Over time each zone within the urban system of Taip ei metropolis evolves as a result of energy convergence and is forced to adapt its internal structure in response to external changes. Simil ar to care in ecosystems, it is concluded that urban systems exhibit i n the long run a certain morphogenesis, a qualitative change in dynami cs which moves an urban system toward different stages of spatial orga nization.