When Cities Grow Wild - Natural Landscaping from an Urban Planning Perspective

by John Ingram

2.1 The Problem with Conventional Urban Landscapes

As a landscape form, turf dominated landscapes studded with the occasional, exotic horticultural specimens have become the universal expression of the urban landscape. Indeed, the mown grass urban and suburban landscape has become the dominant managed landscape expression outside of our agricultural systems (Feagan, 1997). From Halifax, Nova Scotia to Halifax, Australia one can find the same structural patterns and aesthetic principles, a blandscape some critics have called it, endlessly repeated without regard to the regional climate, local soils, topography and other environmental constraints (Cosgrove in Kristensen et al., 1993). Certainly, many of the landscapes might serve specific cultural and recreational purposes, but their production and ongoing maintenance reflect outdated assumptions about both urban and ecological systems. Planned and designed exclusively for human amenity, they take for granted the inexpensive and abundant availability of energy and materials; they assume healthy civic fiscal resources; and they suppose the infinite capacity of the environment to handle the toxic by-products their upkeep creates through such things as emissions from lawn mowers and pesticide and herbicide run-off (Wilson, 1996; Hough, 1995). Conventional landscaping also favours horticulturally cultivated exotic species to native plant species5. With their reliance on regionally and nationally exotic plant and tree species, they represent wholesale biological replacements of the natural communities that preceded them and, therefore, undermine efforts to preserve global, regional and local biodiversity.

These manicured landscapes are not natural. They are manufactured products made solely for human consumption and enjoyment. Further, they enforce cultural attitudes and perceptions that may be considered significant roadblocks to both the promotion of civic environmental stewardship and the larger goal of urban sustainability: first, they are a constant reflection of the detachment of modern society from nature and enforce the naive concept that the city and the larger environment, or natural world, are mutually exclusive and independent; and second, the intensive horticultural management these landscapes demand strengthens anthropocentric notions of superiority and control over the natural world (Feagan, 1997; Nassauer, 1997; Roseland, 1995; Rappaport, 1993; Hough 1990 and 1995).

Such attitudinal effects are compounded when, with the exception of rare remnant natural areas and urban wilderness parks, the grass monoculture represents the closest many city dwellers will ever come to experiencing nature and natural processes first hand. Even in smaller cities like Halifax where access to the country and nature is relatively easy, work schedules, individual motivation and less than universal access to private or public transportation ensure that the dominant experience for city dwellers is of the city itself. As landscape architect and urban designer Michael Hough writes:

Although the environmental movement is changing perceptions, the acceptance of nature [in the city] is still a function of how it conforms to a predetermined set of values and to what extent it is under control. (Hough 1995, p8)

In short, in light of current environmental knowledge and ecological understanding, the current doctrine of urban landscape management is in dire need of reconsideration. To be sure, such a reevaluation process will be difficult given the deeply rooted aesthetic and cultural preference for the current picturesque landscape patterns. However, the failure to fully integrate environmental considerations and priorities into landscape management, this thesis argues, will not only indirectly undermine larger international and local environmental efforts, but also directly erode human health and quality of life.

2.1.1 The Evolution of the (sub)Urban Landscape

The manicured landscape ethic so prevalent in Halifax and other cities is reflective of a long and deeply rooted cultural tradition which should be reviewed prior to examining the specific negative environmental and societal implications associated with present landscaping conventions. It is, in fact, western society's aesthetic preferences for such landscapes that pose the biggest challenge to the acceptance of natural landscaping and the adoption of an alternative landscape ethic.

Until very recently, the underlying disciplines, such as engineering, planning, urban design, architecture, even landscape architecture, that shaped the city and its suburbs have had very little to do with environmental science (Hough, 1995). Parks, private gardens and formal open space were all designed, and are now maintained, solely for human benefit (Gornham, 1997 in Nassauer, ed., 1997). This fact is clearly reflected in today's civic landscapes and private horticultural practices, both of which are based upon historic aesthetic values and experiences separate from contemporary environmental concerns and ecological knowledge.

The predominance of urban landscape ethic, can be traced to two especially important historical events. The first was the pastoral or picturesque English landscape gardening tradition in the early 18th Century, and second was the City Beautiful movement which began in the late 19th Century6.

The earlier picturesque movement began in the early-eighteenth century when English landscape gardening rejected French and Dutch rigid formalism for a freer, more naturalistic appearance (Nivala, 1988). Famous for their sweeping meadows and picturesque, tree studded vistas, the great English gardens of the period were intended to celebrate the power and beauty of nature. It was, however, a highly romanticized, pastoral and fundamentally domesticated natural landscape that demanded tremendous upkeep to maintain its bucolic appearances (Nassauer, 1997; Nivala, 1988)7.

Over time, the periods landscape design values ultimately found their way into North Americas first urban parks. Olmsted's Central Park is a classic example of a park created in the aesthetic tradition of the grand English garden. As Rutherford H. Platt writes in his book, The Ecological City, "Olmsted's goal was not to preserve the somewhat meagre natural qualities of the site as it was, but rather to create a pseudo rural countryside" (Platt, 1994).

It was in this pseudo rural tradition that Olmsted planned and built one of the first suburban residential development on the outskirts Chicago. Called Riverside, the designs specified that houses be set back a minimum of thirty feet from the sidewalk (a departure from the urban standard of homes abutting the sidewalk), ornamental trees be placed along street boulevards and no fence or hedge boundaries placed between the houses, all to ensure that the broad unfragmented lawns and scattered vegetation met the pastoral, picturesque ideal (Jenkins, 1991 Clarke, 1994) As is evidenced in today's suburban designs, Riverside set the tone for suburban landscape development. Although Olmsted felt strongly about people having contact with nature, his was an ecologically denuded celebration of nature.

Compounding the unintended environmental impacts of the picturesque landscape tradition are the lingering aesthetic values of the City Beautiful movement of the late 19th and early 20th century. The movement transplanted to American and Canadian cities the elements of the grand Baroque plans of nineteenth-century imperial European capitals and its attendant formal landscaping (Platt, 1994). The single word to describe City Beautiful was monumental; its design ambition, timelessness. With it came the civic horticultural flourishes so universally applied as to become common and monotonous: the grand expanses of grass surrounding public buildings; the arrow-straight rows of pruned, single species boulevard trees with no understory except grass; and the borders of lollipop-pruned shrubs in elevated, concrete planter boxes. As with the preceding romantic landscape ethic, nature, as it were, was celebrated, but conceived of in terms of strictly human ordained purposes (Raglon, 1991, p17). Natural elements provided the City Beautiful its aesthetic finishing touches rather than its first principles, with plants and natural processes adapted to rigid visual preferences regardless of the underlying ecological structures and needs(Wilson, 1992; Hough, 1995).

In summary, the picturesque landscape movement transformed an already manipulated landscape to look like the romantic paintings of the period. This landscape came to be seen as both beautiful and natural, and was used as the model for large urban parks in North America, where any naturalness was further diminished. Applied to this were even more explicit demonstrations of human centredness and superiority, City Beautiful, and a legacy of urban landscapes made entirely for a narrow definition of human pleasure and greatly separated from nature was created.

ing200.jpg (43507 bytes)Figure 2.0

The Conventional Park

Park trees in a line, set into turf. Pretty to look at for some, but nearly devoid of ecological vitality and stability. When these trees die, there is nothing to replace them. They also present limited habitat for birds, insects and small mammals.

(source: Hough, 1995)

Of course, this omnipresent landscape ethic is best witnessed in the residential suburbs where the horticultural homogeneity is played out on a vast scale. It is, in fact, to the period of massive post-war suburban development that we owe the codification of this landscape ethic into law. As will be discussed further in Section 3.1.1, special by-laws and ordinances were developed during this period to ensure that certain aesthetic tenets were met by homeowners to maintain the visual conformity so important to the marketing of the new developments (Rappaport, 1993). Indeed, the suburbs were packaged and sold on their pastoral landscape merits, maintenance of which was a symbol of civic responsibility and pride. Although its gender assumptions might not sit well with the some people today, the message from a 1950s lawn care industry booklet still ring true for suburban landscape today.

The lawn is an American Institution, like apple pie or Fourth of July. It's a living carpet of green supporting, blending, and delicately enhancing the beauty and loveliness of natures many other creations. Its the outer domain of each mans realm and the welcoming symbol of each mans castle. (from Reed, 1994. p37)

Conventional landscaping standards are not limited to the suburbs. They are virtually universal, their attached cultural values, pervasive. There is, in fact, a unique symbiotic relationship in play, as our anthropocentric culture enforces the predominant urban landscape aesthetic, and the aesthetic, or landscape ethic, in turn enforces our anthropocentrism. With the dominance of the present landscape ethic established, the next section discusses its inherent environmental, economic and societal impacts. It is through understanding the costs of conventional landscaping that the case for natural landscaping becomes ever more reasonable, if not imperative.

2.1.2 The Real Costs of Conventional Landscaping

Although outwardly appealing and pretty to many people, the legacy of manicured park lands and greenspaces is not without negative environmental, societal and environmental implications. As any gardener can attest, subjugating the natural dynamics of plant succession to maintain desired visual and physical effects takes enormous energy and time (Hough, 1995). Ecologically and scientifically speaking, urban and suburban landscapes have notoriously simple structures (large areas are monocultures) whose non-diverse ecosystems are dependent on high energy inputs for stability (Lyle, 1985). From a municipal perspective, these energy inputs are most clearly manifest in the costly maintenance demanded by the upkeep of public parks, gardens and open spaces. Yet the scale of input goes beyond pure financial terms. Many of the quantifiable inputs procured through maintenance budgets, such as gasoline for maintenance equipment, fertilizers, pesticides, and herbicides, carry significant output costs in terms of environmental, public health and ecological impacts. It is these outputs that carry far greater long-term costs in their pernicious and pervasive effects on environmental health generally and human health particularly (e.g., ground water pollution from pesticide run-off, atmospheric pollution from lawn mower emissions, etc.).

The following sub-sections provide a brief overview of some of the impacts and costs directly attributable to the ongoing maintenance and development of the current landscape ethic. Again, as the problems are not isolated to Halifax, the associated costs and impacts are examined in a broad context. Additionally, statistical data is not available regarding land devoted to traditional parks, gardens and formal open spaces for Halifax Regional Municipality as a whole, nor regarding the associated environmental problems. Nevertheless, the information presented in the following sections is still relevant in framing the thesis question and, with appropriate scaling, an be readily applied to the local situation in Halifax. Ecological and Environmental Costs

In environmental and ecological terms the contemporary, horticulturalist landscape ethic carries with it enormous costs. The following statistics serve to provide both an introduction to and indication of the range of the problems associated with conventional landscape maintenance.

With the near universal application of conventional landscaping standards in North American cities today, the impacts suggested by these statistics are compounded to alarming proportions when one considers the total land area devoted to the practice. Although some might consider urban greenspaces to make up a relatively small and insignificant proportion of the urban landscape, as a whole the land use likely does not. Despite the fact that no clear estimates for total urban greenspace exists, basic calculations conducted for this thesis determined that private and publicly maintained vegetated areas probably occupy an absolute minimum of 10% of the land area of most North American cities9. The calculation considers these four facts: first, lot coverage requirements for most residential neighbourhoods restricts building coverage to 35% to 40% of the total lot area; second, the area given over to low density residential areas typically accounts for upwards of 50% of most urban municipalities land areas; third, as it is commonly estimated that upwards of 30% of urban land is dedicated to streets and road right-of-ways one can guesstimate using standard street measures that the percentage of vegetated boulevards, road verges, cul-de-sacs and medians included in this figure accounts for a minimum of 1 or 2%; and fourth, according to a recent City of Halifax study even the most park poor city in Canada, Edmonton, provides 0.4 hectares of formal parkland per 1,000 residents, or almost 3% of its land area (City of Halifax, Development and Planning Department, 1996; Hough 1995)10. Taking these percentages into account, therefore, it becomes evident that the amount of land dedicated to conventionally vegetated landscape features is considerable. By extension, the particular land uses cumulative environmental impacts must also be significant.

With a rough picture of the minimum land areas given over to conventional landscaping in urban and suburban areas, the following sub-sections explore the general environmental impacts associated with the land use. Biological impacts are dealt with first, followed in order by climatological, hydrological and finally atmospheric implications.

Biodiversity Impacts

Simply considering the amount of land typically dedicated to conventionally vegetated private and public landscapes speaks to proportionate losses in regional biological diversity. The maintenance of biological capital depends on spatially and ecologically diverse landscapes of the sort urban development is displacing at considerable speed. Formal vegetated landscapes with their simple internal structures can in no way substitute for the comparatively diverse, varied and dynamic ecotypes they replace (Romme, 1997 in Nassauer ed. 1997). Certainly some cultivated species provide some ecological value, notably many branched shrubs and conifers which provide wildlife habitat, but their benefits are far less than those offered by complete native plant communities (Ruderon, 1997). Many species of local biota, such as birds, small mammals, insects, have evolved to become so dependent on the complex relationships with their native plant communities that they often can not survive when the plant communities are displaced by exotic, cultivated species. Certainly, there are those few species which have adapted themselves to the urban environment, but often, as in the case of the raccoon or skunk, for example, they are perceived as wildlife nuisances.

Although figures on biota reductions are limited, the Missouri-based Center for Plant Conservation has determined that the long-term survival of 4,279 of Americas 23,000 native plant species is at risk primarily because urban growth patterns and horticultural practices (Bezanson, 1995, p3). The potential scientific and medicinal information lost if these species are allowed to become extinct are incalculable. Biodiversity, as one author put it, contains the accumulated wisdom of nature and the key to its future (Meine, 1997 in Nassauer ed., 1997). As F. Herbert Bormann writes in his book, Redesigning the American Lawn:

It may be time to link the local extinction that occurs in our backyards with the world decline in biotic diversity. The spread of the lawn and its accompanying destruction of native habitat may have a serious cumulative effect on the nations flora and fauna, especially on plant and animal populations of limited size that occur in small, specialized habitats. (Bormann, 1993 from Clark, 1994, p41)

The use of pesticides and herbicides on conventionally maintained landscapes compound the problem of habitat destruction and add to the loss of regional biological diversity. Despite manufacturers claims to the contrary, many commonly applied pesticides and herbicides are neither harmless, nor specifically formulated to affect only their intended targets. The majority contain persistent and dangerous chemicals that are responsible for the by-kill of indigenous and beneficial plant and animal species (Real Alternatives to Toxins in the Environment organization, 1998). Some chemical pesticides and herbicides damage soil by destroying beneficial organisms such as worms, fungi and bacteria. Others slowly build up, or bio-accumulate, in the food chain and impact the health and birth and mortality rates of higher species including birds, small mammals and even humans. Pesticide exposure has been clearly linked to a series of plant, animal and human effects including genetic mutations, birth defects and a variety of cancers (Real Alternatives to Toxins in the Environment organization, 1998; EPA, 1997). Although a full discussion of the many environmental impacts clearly associated with pesticide use is beyond the scope of this thesis, Appendix 4 provides a table of some of the human health impacts associated with common chemical lawn care products11.

Climatological Impacts

Climatologically, urbanized landscapes in general have had a tremendous and complex impact on local and regional climates resulting in such phenomenon as the urban heat island (warmer temperatures in cities as compared to surrounding rural areas). Although these effects are also a result of the built landscape forms, construction materials and waste heat outputs, common vegetated landscapes are nevertheless part of the larger problem. Specifically, when compared with their naturalized or forested counterparts, mown grass landscapes allow far greater wind velocities, have a reduced evaporo-transpiration quality and permit greater direct solar radiation to the ground (Hough, 1995). Together these qualities compound negative urban micro-climate associations. Even though greenspaces are a small part of cities, intelligent and thoughtful use or preservation of native planting can ameliorate local microclimates. This will be further discussed in section 2.2.1.

Water Quality and Hydrological Impacts

In combination with their climatological effects, conventional vegetated landscapes have profound effects on local hydrology with significant environmental costs. The reduced permeability of turfed areas ultimately reduce groundwater infiltration and add to overland storm water run-off, increasing the frequency of localized flooding and negatively altering downstream water course characteristics (Lyle, 1985). The downstream environmental effects of overland storm water flow is compounded by the typical fertilizer, herbicide and pesticide applications most lawns and gardens receive. Together these synthetic and often chemically persistent products seriously impact biotic communities and degrade both surface and groundwater quality. This is to say nothing of the profound human and environmental health problems associated with pesticide and herbicide use in the first place.

Additionally, given their shallow root systems, lawn areas are more prone to erosion and can increase local waterway sediment concentrations by as much as 1000 times (Hough, 1995)12. Finally, the wholesale land moving operations that are often a part of contemporary landscape creation retard local drainage characteristics and increase occurrences of local flooding.

Air Quality Impacts

In terms of atmospheric pollution, the two stroke engines that typically power both industrial and residential maintenance equipment are notoriously inefficient and not subject to the same emissions standards as vehicles. They do not have catalytic converters and they burn a mixture of oil and gas. Carbon monoxide, carbon dioxide, nitrous oxides, sulphur dioxide, volatile organic compounds, particulates and toxins such as benzene are all emitted in considerable quantities. Gasoline powered lawn and garden equipment, on average, produce 5% of ozone-forming VOCs in areas with smog problems (EPA, 1998). In addition, mown turf grass have very limited vascular surface areas and shallow root systems which limit their ability to both intercept air born particulates and to make effective carbon sinks (North Eastern Illinois Planning Commission, 1997). A recent research paper in the journal Science, showed that native grasses are significantly better at sequestering carbon dioxide than exotic species (Wildflower, 1996). The same article determined that the atmospheric nitrogen deposition rate has increased tenfold as a direct result of the use of nitrogen fertilizers for lawn care alone. The increased nitrogen levels were found to pose a major threat to grassland ecosystems, in particular. Maintenance Costs

A hunger for the control of large-scale form is all the more dangerous because it coincides with strong contemporary trends towards large-scale investment. (Kevin Lynch, 1976 quoted in Hough, 1990, p90)

In purely fiscal terms, the maintenance costs of conventionally managed landscapes are in direct ratio to their considerable energy requirements. For publicly maintained sites, gasoline or electricity for the maintenance equipment, transportation of equipment, crew to and from the site, tipping fees or composting costs for grass clippings, leaf litter and other organic waste material, synthetic fertilizers, pesticides and herbicides, sod, seeds, water treatment and irrigation, bulb, shrub and tree costs should all be considered when tallying a final figure (not including the embodied energy represented in all equipment, fuel and supplies). Although costs vary substantially from site to site, they are nevertheless considerable.

The true maintenance costs of conventional landscaping are hard to determine specifically, as they are typically buried in general departmental budgets along with such things as recreation facilities management and maintenance costs. For municipally maintained turf landscapes, however, a good estimate is roughly US $1,200 per acre per year, or CAN $4,000 per hectare per year (Northeastern Illinois Planning Commission, 1997). This figure, of course, does not include the environmental externalities associated with park and grounds maintenance, such as ground water contamination by fertilizers and pesticides.

It is, in fact, the high costs of turf grass maintenance that have ultimately driven many jurisdictions to explore natural landscaping and/or redevelop and reduce parks and grounds service standards and mowing regimes (Feagan, 1997). A series of interviews conducted for this thesis confirmed the significance of budgetary constraints in reconsidering the management practices of public landscapes13.

In the private realm, significant amounts of money are also spent on turf and garden maintenance. Annual expenditures on private lawn care in the US alone come in at US $25 billion, with US $5.25 billion of this figure spent on fossil fuel-derived fertilizers and US $700 million on pesticides (Bormannn et al, 1993). Societal Implications

One of the most popular messages of the environmental education movement today is that caring for the environment begins at home. What is meant by home in this case is a private residence and caring, for the most part, involves cutting down on packaging, recycling, and avoiding the purchase of household hazardous products. Certainly, this is a good start, but it also misses an extremely important conceptual point: home is not just our house, but the larger reality, the environment, within which it rests.

Ecosystems composing an urban landscape, even formal, intensively managed urban greenspaces, interact by exchanging energy, materials and organisms with one another. These interactions vary greatly, both spatially and temporally, but they all ultimately connect to form, shape and drive the global meta-system, or Gaia (Lyle, 1985). In short, we are all connected. Yet, this profoundly important fact is not communicated by our manufactured urban environment. Nor can we blame the majority of our educators for missing it. The urban landscapes we have built and continue to manage do not teach us what we should really be learning if we sincerely want to be good environmentalists.

What do our current parks, gardens and other contemporary urban landscape forms teach us? That grass and plants that are left to grow are unsightly and somehow wrong? That springtime is when the pansies are planted? That ecology and culture are two distinct and independent realms? Indeed, our current models not only make local ecological connections hard to establish but they underscore the destructive notion that modern society is separate from nature, and drive the perception that the vegetated urban landscape must be regimentally cut, pruned and controlled if it is to be healthy and beautiful (Hough, 1990; Rappaport, 1993).

Perpetually green lawns, like a plastic tree, implicitly reduce the entities they portray in terms of serviceability, utility, and adornment, writes Bret Rappaport a Chicago-based attorney and natural landscaping proponent, And such caricatures in turn reinforce the belief that the depicted objects exist not for themselves, but to service superior human needs (Rappaport, 1993, p873). As a recent report by the Federation of Canadian Municipalities (FCM), the Canada Housing and Mortgage Corporation (CMHC) and Environment Canada commented:

While environmental concerns remain high, environmental considerations are not well-integrated into individual or societal decision making. This is linked to the commonly held belief...[that]... humans are separated from and superior to the species in the natural world. This belief is reinforced by the fact that many urban dwellers have little experience with natural areas, given that their urban centres are often lacking in biodiversity. Instead, they are surrounded by engineered environments which contribute to the perception of our separateness form nature. Cities, in particular, are considered by many to be places unworthy of environmental concern. The environment is not in the city, it is somewhere else. (from: The Ecological City: Canada's Overview - CMHC, FCM, Environment Canada, 1995 p 61)

In short, the manufactured landscapes we favour serve to confound the potential of current environmental education campaigns or programs; they perpetuate wrong minded ideas of nature in the city, and they express values conspicuously out of date with current environment knowledge and practice.

ing201.jpg (42994 bytes)Figure 2.1
What is the lesson here?

Urban development routinely confines, stunts and perverts natural processes and landscape functions. It is the nature of cities. Unfortunately landscapes like this perpetuate negative perceptions of the value and worth of nature in the city.
(source: Hough, 1995,)

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