Planning June 2014

Reconsidering Ian McHarg: The Future of Urban Ecology

Book ponders the legacy of a renowned landscape architect and author, in the context of a densifying urban world.

By Ignacio F. Bunster-Ossa

Design with Nature represents a milestone in the era of emerging environmentalism. At a time when the national drive toward suburbia was accelerating, Ian McHarg's book, published in 1969, caused people to pause and ask, "How can the trail be blazed without searing the landscape?" His signature achievement, the ecological planning method, provided an answer. Since then, tens of millions of homes have been built in the countryside, remaking the rural landscape into a sprawling haven for single-family homes, with sensitive ecological resources duly preserved.

Today, the triple-bottom-line sustainability objective — environmental health, economic development, and social equity — call into question the viability of suburban development as a societal aim. The fuel consumed in personal transportation, the ever-longer commutes, and the inefficient dispensation of municipal services required to sustain far-flung communities is no longer economically or environmentally viable.

Regardless of environmental planning's correctness from an ecological standpoint, no amount of spared woodlands, wetlands, erodible slopes, riparian stream banks, or aquifer recharge zones can mitigate the health and social impacts of distant subdivisions that induce automobile dependence. The counterbenefits of a half-century of sprawl, coupled with the unrestrained consumption of energy in buildings and transportation, have placed the nation at a tipping point.

Ian Mcharg

As Thomas Friedman noted in a New York Times editorial in April 2012, "With Europe in peril, China and America wobbling, the Arab world in turmoil, energy prices spiraling and the climate changing, we are facing some real storms ahead. We need to weatherproof our American house — and fast — in order to ensure that America remains a rock of stability for the world."

Weatherproofing the American house — the nation — requires a fundamental rethinking of the national urban landscape. Smart growth provides vital guidance: more compact, walkable, transit-oriented communities that preserve open land represent positive development goals. Equally important is denser placemaking for home and work that proves to be eminently more desirable than a suburban alternative.

In examining the issue of environmental quality in the context of urban densification, three fundamental necessities arise:

  • Green Infrastructure, as the means to integrate a "working nature" in the urban midst
  • Localism, as the means to reaffirm the value of culture and community life
  • Public Art, as the means to exact from everyday life a measure of rooted meaning, beauty, and sublimity

These are the strands that underpin the concepts of an urban ecology. While the subjects of green infrastructure, localism, and public art have been well discussed individually in the planning and design fields, and case studies abound in each instance, comparatively little has been done to fold them together holistically as an urban ecology. That's what I am trying to do, because ecology is a unifying and binding agent — as a science, to be sure, but more importantly as an ethic that enfolds matter and spirit as planning and design concerns.

The notion of a climax city — borrowed from ecology — is the indispensable product of this ethic. An ecological climax predicates the sustained adaptation of organisms to a given set of environmental conditions, climate being among the most critical. If it is accepted that the environment of an urban area — a densifying urban area — should be conducive to a sustained human adaption (presuming the aim of health and well-being), then there should be an optimal way to build them or build toward them.

The notion of ecological climax can be challenged by scientific evidence to the effect that natural systems are in constant flux — that a climax community in nature is nothing more than a temporary state of biotic balance within an evolutionary arc. This is an argument made by Daniel Botkin in his 1990 book, Discordant Harmonies. Still, a climax state ultimately represents an efficient use of resources (sunlight, water, nutrients) to the sustained benefit of flora and fauna at a given point in time. The question is this: How should cities, as human habitat, deliver an optimal environment at this point in time, given present needs and aspirations?

In considering how to progress toward a climax urban state, three operational scales become useful: city, community, and building. Owing to the value of open space in advancing urban quality and identity, it is further useful to accord to these scales a corresponding planning and design typology, namely landscape, park, and garden, respectively.

A planning and design hierarchy is thus established, facilitating the consistent fusion of infrastructure, localism, and public art across scales of development.

The proposed new design for Constitution Gardens at the Mall in Washington, D.C., evokes the city's original marshland setting through new wetlands bordering an extant lake

City as landscape

"Landscape" is the representation of nature and culture as interdependent and coevolving producers of what we see as we move about the land. Embedded in "landscape" is the beginning of everything — the raw land that became settled as a result of human imagination and toil. The ecology that underlies this land, whether extant or not, can become deeply held as part of the story of community.

Knowing this ecology was central to McHarg's pedagogy. In Design with Nature, the physiography of Washington, D.C., is presented as a way to explain the relationship of federal facilities to the underlying bedrock.

Of note is the U.S. Capitol. The building rests on a high point along the Pamlico-Wicomico geologic escarpment, a feature that fully supports the civic need for symbolic prominence, as McHarg put it. In time the lowlands west of the escarpment became the National Mall, portions of which flood during heavy rainfall. The National Park Service has planned a floodgate near Constitution Avenue to prevent rising waters from extending past the Mall and into the city.

Near this gate is Constitution Gardens, a 50-acre site created for the national bicentennial in commemoration of the American Revolution. Its curvilinear pond and surrounding informal landscape provide a faint echo of the natural habitat that existed close to the Capitol and White House at the time Pierre L'Enfant planned the nation's capital.

In 2012 the Trust for the National Mall chose new designs for Constitution Gardens through a national design competition. The winning entry, by Peter Walker & Partners in association with Rogers Marvel Architects, reinforces the informal quality of the landscape through curving paths and rolling topography. It also proposes a ring of emergent vegetation at the edge of the pond, a green infrastructure measure that recalls the marshlands that once defined the setting of the nation's capital.

Places like the National Mall that in parts evoke or reveal a city's founding landscape foreshorten the path between the eye and the soul. Doing so sustains the link between past and present, according urban places a measure of poetic resonance. Cities such as Orlando, Florida, and San Francisco provide even broader examples. Orlando does so through parkland that surrounds many of the notorious limestone sinkholes that dot the city — Lake Eola, the oldest and most perfectly shaped, being a downtown landmark. In San Francisco, the street grid extends over steep hills without regard to contour or slope, magnifying the terrain over which it lies. In both cases, the geologic substrate has become a civic cause celebre.

San Diego provides a regional example of an urban identity molded by natural features. The city is characterized by finger canyons that cut through the gridded urban mesa; by broad valleys that collect major drainage, transportation, and big box retail; and by embayments that capture the downtown skyline and major recreational and visitor attractions.

In the classic 1974 study, Temporary Paradise?: A Look at the Special Landscape of the San Diego Region, Donald Appleyard and Kevin Lynch defined the geophysical structure of the city, calling for the preservation and enhancement of the bays, valleys, and canyons as essential city-shaping elements. Few studies so clearly establish the power of, and dependency on, a city's foundational landscape as a guide toward growth and development.

Parklets are among the features that enliven the everyday environment of West Philadelphia. They are becoming popular characteristics of complete streets

Community as park

As a physical realm, "community" signifies the space where discrete populations move about to and from home, work, school, and services. Historically, such a realm has been largely treated as the antipode to urban parks — the gritty environment that makes green open space a necessary exception in the first place. The value of New York City's Central Park derives to a great extent from the greenery it offers in contrast to the built-up blocks that surround it. As stewards of the park, the Central Park Conservancy proudly promotes such distinction, referring to the park as "a green oasis in the great concrete, high-rise landscape of New York City."

But what if the "grit" of the city were a green amenity in and of itself? What if it became parklike? Philadelphia intends to add 500 acres of recreational space within existing neighborhoods, as called for by its Green 2015 parks master plan. This is commendable, yet in Philadelphia, as in most cities, finding cost-effective space for new parks within a safe and amenable walking or biking distance from most people's homes remains a challenge.

Outdoor recreational needs must be met by also maximizing the recreational and green, that is, "living" quality of the everyday environment: the sidewalks, trails, alleys, streets, avenues, boulevards, and odd leftover public areas that typically comprise approximately half the land in any given city. Owing to their potential as active mobility corridors, streets and greenways become especially important as green amenity venues.

Much can be said about the benefits of the complete streets efforts that are slowly changing the character of the nation's urban thoroughfares. This initiative addresses modes of transportation, while its environmental cousin, green streets, is focused primarily on stormwater management.

Under a "climax" scenario, streets would function as livable, everyday amenities, an extension of a city's mobility, environmental, and recreational matrix. "Living streets" should invite an elderly person with a grandchild to sit and rest, to say hello to neighbors and friends, to smell a flower, hear birdsong, or interact with artwork. Street art, from graffiti works, murals, and temporary sidewalk paintings to word art, sculpted furnishings, and periodic art performance, should be fully integrated with complete streets and green streets programs.

Design proposals for Raritan Avenue in the city of Highland Park, New Jersey, were designed following the "living" street model. The improvements addressed the public space component of a revitalization plan for the town's principal commercial corridor. Of special note are "living room" street corners with sofalike benches, side tables, and art-crafted carpets of patterned recycled glass, a symbol of the community's toddler-to-grandparent sociability and welcoming multiculturalism.

The street corners flair out behind side-street rain gardens that collect localized stormwater, an expression of this small town's outsized belief in a sustainable "steady state." (The Highland Park Streetscape was spearheaded by former Mayor Meryl Frank as part of a 2005 downtown revitalization plan. Both the streetscape and revitalization plan were prepared by my firm, Wallace Roberts & Todd.)

To be sure, not every street in every city needs such treatment. But every community should have such corridors, especially along high-traffic pedestrian and bike areas associated with schools, services, shopping, and local parks. This is a growing need: In market preference surveys, walkability and "life-cycle mix" are listed as the top desired conditions of a healthy neighborhood — by far.

Building as garden

From the early paradise gardens of the Middle East, the Pompeian courtyard, the medieval cloister, the Moorish palaces of southern Spain, the English Winter Garden, and the modernism of Wright and Alto, to present day "green" architecture, the need to bring a measure of healthy air, light, water, and greenery into the built environment — to inhabit, in effect, a garden — has been a recurrent building tradition.

Arguably, the green architecture movement began in Malaysia in 1993 with the completion of Menara Mesiniaga. This 12-story building, designed by Kenneth Yeang, employs natural ventilation techniques and the multistory integration of vegetation to effect cooling.

Today, the integration of infrastructural greenery in buildings is becoming ever more prevalent, especially for institutional commissions. The U.S. Coast Guard Headquarters complex in Washington, D.C., sprawls across the hillsides of Anacostia like a modern-day Alhambra, with water-filtering green roofs and water recycling ponds diffusing the line between building and landscape. In San Francisco, the California Academy of Science is topped by an expansive, swelling vegetated roof as if the surrounding coastal range had washed over it.

But "green" by itself does not constitute a "climax" architectural state. Artistic intent must be part of the garden ideal. As architect, artist, and educator James Wines argues in Green Architecture, "Too often the problem with so-called green architecture is the conflict between having an admirable commitment to ecological design . . . and a failure to convert [such] noble objectives into an equivalent artistic expression."

In this regard, Wines's work is both singular and pioneering. In 1981 his firm, SITE, proposed "Highrise of Homes." The conceptual proposal consists of a 12-story building for "single-family homes," one or more per structural bay, landscaped yards included. As a "matrix of housing choices," the work represents an antidote to the alienating, depersonalized effect of industrial architecture. (Wines's book is among the first comprehensive reviews of the genre.)

Realized examples of Wines's fusion method were made manifest through the design of several Best Products stores. In Richmond, Virginia, one of them evokes nature's revenge on humanity's degrading consumerism by simulating an architectural ruin overtaken by wild vegetation.

In a Vienna apartment building bearing his name, artist-architect Friedensreich Hundertwasser showcased the fusion of art, greenery, and architecture as never before conceived or attempted. The result recalls the baroque in its fluid and exuberant plasticity. Soon after the building was completed in 1985, a "tree-tenant" emerged from an upper story window. Reaching out tenuously from the interior darkness, the tree seemed to beg a reassessment of humanity's building ethics, at once blaring the call for a healthier way of living and reminding us of our paradisiacal (but lost) beginnings.

Green buildings must embrace the human spirit as a means of transcending physical well-being. Like gardens, green buildings must exhibit a fractal array of solids and voids, each loop tracing the larger body of infrastructure and art as a unified and sustaining habitat. Under a building-as-garden practice, no two buildings would be alike, each an efflorescence of localized bedrock, both concrete and abstract. In this context, planning and design become exercises of discovery and invention, of marking ground as a possibility of green and artful composition.

The opportunity at hand matches the challenge: Ethan Seltzer and Armando Carbonell, AICP, predict in their 2011 book, Regional Planning in America, that "the United States will require nearly three-quarters as much new built space over the next two decades — homes, offices, stores, warehouses, and so forth — as has been built over the past four centuries."

A vast new array of places can therefore be designed to meet the imperative for better, healthier, and more efficient cities, from the breakfast nook to the workplace and every mode of public infrastructure in between. In denser towns and cities the possibilities for ecological placemaking will multiply, expanding the opportunity for individual and collective wellness.

McHarg spoke powerfully, effectively, and incessantly about the need to save the environment from abuse and despoliation in the hands of uninformed developers and enabling public bureaucracies. In doing so he may have contributed to the spread of development well into the hinterland. His call to build a healthier and safer world protective of our most precious environmental resources remains as valid today as when Design with Nature was first published; but today it is cities that are the precious resource.

Cities now constitute our natural milieu, and as such, they must be qualitatively elevated from a landscape and building standpoint. Planners, urban designers, architects, landscape architects, artists, engineers, and a host of related experts must come together to effect such elevation. A unity of the arts must be pursued and achieved. And, as McHarg preached, ecology must remain the common theme, systematically applied. But this now must be a complete ecology that, through art, fuses matter (green infrastructure) and spirit (localism) into building blocks for our earthly abode.

Ignacio F. Bunster-Ossa is a principal at Wallace Roberts & Todd, the Philadelphia planning and design firm that McHarg founded with three other partners. This article is excerpted from Reconsidering Ian McHarg.


Images: Top — Ian Mcharg. Photo courtesy Ian McHarg collection, The Architectural Archives, University of Pennsylvania. Middle — The proposed new design for Constitution Gardens at the Mall in Washington, D.C., evokes the city's original marshland setting through new wetlands bordering an extant lake. Image courtesy PWP Landscape Architecture. Bottom — Parklets are among the features that enliven the everyday environment of West Philadelphia. They are becoming popular characteristics of complete streets. Photo by Ignacio Bunster-Ossa.

Ian McHarg's book, Design with Nature, was originally published in 1969 by Natural History Press.

See also: Thomas Friedman, "One for the Country," New York Times, April 17, 2012; Daniel B. Botkin, Discordant Harmonies, Oxford University Press, 1990; Donald Appleyard and Kevin Lynch, Temporary Paradise? A Look at the Special Landscape of the San Diego Region, 1974, available from MIT; Central Park Conservancy, History of Central Park; Arthur C. Nelson, FAICP, The New California Dream, Urban Land Institute, 2011; James Wines, Green Architecture, Taschen, 2000; Ethan Seltzer and Armando Carbonell, AICP, Regional Planning in America, Lincoln Institute of Land Policy, 2011.