Natural Environment and Cities

It is tempting to view cities as places where humanity has annihilated nature and replaced it with artificial landscapes. Such a view, while understandable given the scale of environmental manipulation involved in city building, is overly simplistic. Worse still, it obscures both the nonhuman contribution to urban development in the United States and the ways that cities continue to function as habitats for a wide variety of flora and fauna. Cities are best appreciated as places where ecological systems have been reengineered to accommodate dense populations and to balance the need for economic production with cultural ideals of beauty and health. Over time, increasingly sophisticated and capital-intensive forms of environmental engineering and management have contributed substantially to the simplification and specialization of increasingly interlinked and remote ecosystems. The process has not been straightforward, however. Cities have also been the source of determined efforts to rectify the unintended consequences of environmental modification, particularly where they have endangered human health.

During the pre-industrial era, the commercial ports of North America sustained life for their inhabitants by modifying the natural environment within local exchange and circulation networks. The construction of streets, homes, shops, and churches required a smooth and predictable terrain on which to build. Hills were leveled and the earth recovered in the process was used to fill swamps and other natural depressions. On the fringes of urban settlement, forests submitted to the ax and were converted to farmland to feed urban households. Within cities, a surprisingly wide array of plant and animal life integrated humans into a largely self-contained waste and nutrient recycling loop. Pigs that munched on refuse thrown from windows and doorways ended up as bacon on working-class breakfast tables. Until after the Civil War, cows roamed the streets of some cities, providing a readily available supply of meat and milk; almost every backyard contained chickens for egg production. The horse was perhaps the most ubiquitous of the large urban vertebrates. Horses served an important function, pulling private carriages, public omnibuses, and firefighting equipment. They also produced tremendous quantities of manure, most of which was carted along with human excrement to outlying farms. The crops grown on those fertilized farms then made their way back to the city to replenish the bellies of both the humans and the horses.

A series of reforms associated with the mid-19th-century sanitary revolution rid cities of most large animals and radically altered waste disposal practices. The impetus behind these reforms was a series of devastating cholera and typhoid epidemics that ravaged American cities from coast to coast from the 1830s through the 1860s, claiming as much as 10 percent of the urban population during the most severe outbreaks. The prevailing medical wisdom blamed the diseases on the abundance of decaying waste matter in the urban environment, so the large animals had to go. Pigs and cows were banned from city streets; horses were increasingly maligned but were used for another half-century before they were displaced by the internal [Page 523]combustion engine. A second and equally far-reaching response was the construction of engineered water carriage systems to both bring fresh water into the city and flush dirty water away. In 1842, New York City celebrated the opening of the Croton Aqueduct, which brought in water from a reservoir located 40 miles to the north. During the following decade, cities like Brooklyn, Chicago, and St. Louis began laying underground pipes to flush human wastes from households into the nearby rivers and bays. The new urban hydrology, which was further modified by paved streets, resulted in greater quantities of water passing through the city but less of it flowing through the soil and natural watercourses.

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