A City is a Tree: Chaos, Fractals and Landscape Design

Patrick Miller

In 1966 Christopher Alexander wrote an article titled, “A City is Not a Tree.” He lamented the fact that designed cities that he termed, artificial cities, were not as lively and vibrant as cities that have evolved without the help of designers, which he called, natural cities.  He said that artificial cities have a hierarchical structure of elements and relationships between elements that when diagramed, take the form of a tree, thus his claim that cities are not a tree.  Natural cites on the other hand, hand have more connected inter-relationships that he termed a lattice.  While this presentation agrees with Alexander’s central premise that there is a difference between cities that are designed (artificial) and those that evolve naturally (natural), it suggests that these differences can be better explained by using Chaos Theory and principles of dynamical system.  Dynamical systems are non-linear systems that follow the laws of fractal geometry.  Some call this ordered disorder.  While they lack the predictive properties of linear systems, they do behave in ways that can provide insight to designers who want to design cities and landscapes that are more like Alexander’s natural cities.  Fractals are the basic building blocks of the natural world.  The structure of trees and much of the natural world are based on fractal geometry.  So, maybe cities are trees or are at least tree like.


patrick miller rgbPatrick is a Past President of the American Society of Landscape Architects (ASLA), a Fellow of ASLA and a Fellow of the Council of Educators in Landscape Architecture.  He has worked in public, private, and academic practice in both the United States and Canada, and has held faculty appointments at four major universities, including the University of Washington, the University of Michigan and the University of British Columbia.  For the past 30 years Patrick has taught in the Landscape Architecture Program at Virginia Polytechnic Institute and State University where he was head of the department for 13 years. He is currently Associate Dean for Graduate Studies and Outreach in the College of Architecture and Urban Studies.  Patrick has a B.Sc. in landscape architecture from California State Polytechnic University, an M.L.A. from the University of California at Berkeley and a Ph.D. from the University of Michigan.  Patrick has lectured nationally and internationally on landscape architecture topics and professional education, most recently in China, Australia, Malaysia, and the Middle East.  Through his writing, teaching, and practice Patrick has been a tireless advocate of creating landscapes that are good for people, the environment and the economy.