The Living City By William McDonough 居住的城市(2)

designs that create more positive effects, not fewer negative ones. This goes for everything from transportation systems to factories to commercial

products to neighborhood plans, all of which can be designed to enhance the city's economic, environmental and social health. How? By following principles derived from nature's laws. In the city, as in the countryside, sustainable design is grounded in the rules of the natural world.

Design and Nature's Laws

Design for sustainability has its roots in the desire to discover fitting ways for humans to inhabit the landscape. As designers, we study the landscape of a particular place by assessing its natural systems: its landforms, hydrology, vegetation, and climate. We tap into natural and cultural history; investigate local energy sources; explore the cycles of sunlight, shade and water; and observe the lives of local fauna, flowers and grasses. As we carefully explore the landscape we might ask: How does the water flow down the hillside and through the valley? How did indigenous people build and live here? What local trees provide abundant shade? From which direction do cooling breezes flow? Out of these investigations comes an "essay of clues," a map for developing healthy and creatively interactive relationships between our designs and the natural world.

This emphasis on the way nature works results in buildings and communities that sustain and enhance the qualities of the local landscape. The "living roof" we designed for a corporate office building in San Bruno, California, for

example, creates acres of habitat for local birds and grasses. When birds fly overhead they don't see a flat, ugly rooftop broiling in the sun, they see a rolling, flowering landscape that looks like home. In Chicago, the green roof we helped design for City Hall is covered with mostly native vegetation, which offers urban habitat to the butterflies and birds of the region. Not incidentally, City Hall's green roof absorbs storm water run-off and insulates the building from the hot sun, provides relief from the urban heat island effect.

In every landscape, nature is our guide. Natural forces express themselves differently from place to place, but as we have worked on projects and

products worldwide, we've identified three key principles that allow us to apply our knowledge of natural systems to human designs. We imagine these principles may have a role in shaping Chicago's future.

Waste=Food. The life cycle of every organism contributes to the health of the

whole. A fruit tree's blossoms fall to the ground and decompose into food for other living things. Bacteria and fungi feed on the organic waste of both the tree and the animals that eat its fruit, depositing nutrients in the soil in a form ready for the tree to take up and convert into growth. In these perpetual cycles-which we call cradle-to-cradle cycles-one organism's waste becomes food for another.

Designs modeled on these cradle-to-cradle cycles eliminate the very concept of waste. A textile we designed, which is woven from wool and ramie and processed with completely safe chemicals, can be tossed on the ground to nourish the soil when it wears out. At the Swiss mill where the fabric is produced, the trimmings serve as garden mulch and the water leaving the factory is as clean as the water flowing in. Synthetics like plastics and metals can flow in cradle-to-cradle cycles too. They can be designed for continual reuse as high-quality materials for industry. A new recycling process, for instance, allows carpet manufacturers to reuse nylon fiber perpetually.

Materials and processes such as these can make manufacturing a restorative act and they will power Chicago's emergence as a green manufacturing hub. Use current solar income. Living things thrive on the energy of the sun. Trees and plants manufacture food from sunlight, an elegant, effective system that uses the earth's only perpetual source of energy income. Buildings can tap into solar income using direct solar energy collection or passive solar processes such as daylighting, which makes effective use of natural light. The winds, too, can be tapped. Winds are thermal flows fueled by sunlight and, along with the sun, can generate enough power cost-effectively to meet the energy needs of entire cities, and indeed, entire nations.

As we have seen, Chicago is already using the power of the sun and the wind. Yet even as it purchases 20 percent of its energy from these sources it has only begun to tap the incredible power of the driving winds of the Great Lakes and the Plains. Encouraging the large-scale development of wind power, and fully integrating solar and wind into Chicago's energy infrastructure will make the City a world leader in the renewable energy industry. Clean power, economic development, thousands of jobs-all by using the energy of the sun.

Celebrate diversity. Healthy ecosystems are complex communities of living things that have developed diverse responses to their surroundings. They provide many models for design. Architects and planners, applying a diversity of design solutions, can create and restore buildings, industries, landscapes and neighborhoods that fit elegantly and effectively into a variety of niches. Why not a diversity of healthy landscapes in Chicago? Imagine inner-city

streams, lakes and marshes becoming home to local endangered species like the black-crowned night heron and the yellow-headed blackbird. Imagine lively street life and prosperous small businesses in neighborhoods blessed with the shade of trees. Imagine restored industrial sites that generate economic prosperity while creating habitat alongside river corridors.

One can see this vision emerging in Chicago and elsewhere in the industrial Great Lakes. Consider, for example, the restoration of the Ford Motor

Company's River Rouge plant in Dearborn, Michigan. There, on a formerly shopworn industrial site, newly planted trees, a ten-acre living roof, and a series of constructed wetlands and swales are restoring soil, creating habitat, and revitalizing the landscape while effectively filtering stormwater runoff for $35 million less than conventional technical methods. When design tunes into biodiversity, even heavy industry can be a regenerative force.

The City as Organism

While nature's laws shape our sense of cities, they don't force us into a static view. We see each city, and we see Chicago, as part of a dynamic ecosystem, a singular evolutionary matrix. And we see the future of the City as an ever more harmonious and creative participation in the surrounding landscape. Claude Levi-Strauss put it well when he described the city as the place where "nature and artifice meet."

"A city is a congestion of animals whose biological history is enclosed within boundaries, and yet every conscious and rational act on the part of these creatures helps to shape the city's eventual character. By its form as by the manner of its birth, the city has elements at once of biological procreation, organic evolution, and esthetic creation. It is both a natural object and a thing to be cultivated; individual and group; something lived and something dreamed."

Cities are made. One can look at a metropolis like Chicago and get the sense that it has always been there. Yet in 1830s Chicago, as William Cronon has written, "one did not have to walk more than a few minutes to be out on the prairie." Just 60 years later booming, urbane Chicago hosted the famous Columbian Exposition.

Cities are designed. The tree-lined boulevards and elegant storefronts of Paris are not the result of lucky happenstance but of an ambitious 19th century renovation that remade the city from the sewers to the rooftops. It is no

coincidence that Paris has remained a cultural capital in spite of the mercurial fortunes of France.

Cities are organisms. They have metabolisms. They are linked to their regions through complex networks, both natural and cultivated, that circulate biological nutrition-food, wood, fiber, water-and technical nutrition-the