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

by John Ingram

2.2 Natural Landscaping: A New Landscape Ethic?

When urban form and function are congruent with deep structure, they are likely to be more functional, economic, sustainable and memorable. Anne Spirn (in Kristensen et al., 1993 p9) In creating landscape forms that work in harmony with the larger environment, natural landscaping represents an attempt to forge a new non-consumptive attitude towards the landscape founded on environmental processes and principles. Natural landscaping is fundamentally informed by and integrates itself with the principles of landscape ecology which approaches the environment as a coherent system, or a whole that cannot be understood from its separate biotic and abiotic components (Nassauer, 1997). Like landscape ecology, it abandons the distinction between human dominated and natural ecosystems and allows for the treatment of temporal as well as spatial changes across landscapes patterned by the relationships between human activities and ecological processes (Marczyk et al., 1993)14. Natural landscaping may also be considered a manifestation of Aldo Leopold's Land Ethic, as it too seeks to integrate ecology, aesthetics and environmental ethics. (Rappaport, 1993)15.

Additionally, as both a design approach and a landscape objective, natural landscaping shares the common themes of long-term protection of the environment and the wise use of natural resources with the larger concept of urban sustainability. Although no standardized definition of urban sustainability exists in current literature, the Canada Mortgage and Housing Corporation and Environment Canada recently determined a working list of key urban sustainability characteristics. Divided between the three broad component strands of environmental, economic and social sustainability, many of the identified characteristics are especially pertinent for measuring the sustainability of current urban and suburban landscapes. To compare the two landscape standards, I developed a simple matrix using relevant sustainability indicators from the report. 

Table 2.0 Urban Sustainability: A Landscape Comparison
Sustainability Characteristic Traditional Urban Landscape Naturalized Landscape
minimal impact on the environment significant impact minimal impact
minimal use of renewable resources dependent on significant renewable and non-renewable resource inputs (fertilizers, water, human resources, etc.) minimal use
balance with ecosystem carrying capacity/self-regulating artificially imposed system dependent on intensive human involvement/regulation/upkeep minimal human management
encompasses sufficiency and ecosystem integrity not related to larger ecosystem, not self-sufficient harmonized with larger ecosystem, inherently self-sufficient
implies dynamic, changing process (rather than steady state) artificially maintained steady state system incorporates dynamic natural processes
recognizes that the urban environment can not be separated from the region of which it is a part landscape unrelated to larger environment landscape tied to larger environment
implies vitality and a social learning process steady state landscape unrelated to social learning processes vital teaching landscape
reflective of economic realities expensive to maintain minimal cost involved

Source: CMHC, 1995 - Measuring Urban Sustainability Workshop Proceedings (left hand column only).

As the above table clearly indicates, traditional urban landscape forms do not hold up very well when measured against the sustainability of those created through natural landscaping. More important still, of course, is the fact that natural landscapes meet the conceptual demands of urban sustainability16. Simply by this fact, natural landscaping offers fundamental advantages over the traditional manufactured landscape.

The following sub-sections expand on the specific and general benefits offered through the practice of natural landscaping. Again, as with the section outlining the environmental and societal costs of traditional landscaping, the following sub-sections provide a broad overview and are not limited to Halifax in particular.

2.2.1 Ecological and Environmental Benefits

The ecological and environmental benefits of natural landscaping are many17. From reduction of non-point source pollution, to habitat creation and preservation of regional biodiversity, naturalized urban landscapes are capable of achieving many positive results. It must be made clear, however, that the practice does not pretend to be capable of fully remediating the urban environment. The following is a brief overview of ecological and environmental benefits.

Reduced Pesticide and Herbicide Use

Naturally landscaped areas do not require the pesticide and herbicide applications traditionally used for the upkeep of conventionally landscaped areas. The native plants and trees used in natural landscaping are genetically adapted to local biotic conditions and, therefore, more inherently resistant to local pest problems than exotic, cultivated species. Also unlike conventionally landscaped areas, natural landscapes help reestablish endemic pest controlling insect and bird species populations which can help keep pest outbreaks to a minimum18.

Additionally, once a native grass, meadow or woodland community has established itself (typically between one and three years) it is able to out- compete even pernicious, colonizing weed populations associated with disturbed sites. Once a canopy has established itself in woodland natural landscape, the understory weeds are shaded out.

Finally, those individuals and public authorities involved with natural landscaping tend to keep with the practices environmental theme and favour biological and/or organic methods of pest control over chemical means.

Habitat creation and Preservation of Biodiversity

Natural landscaping can be used to help protect and propagate threatened species and to preserve biodiversity on three distinct ecological levels: first, on an ecosystem level natural landscaping can be used to create and preserve threatened ecosystems such as wetlands; second, on a species level, it can be used to help preserve the complex species associations of the particular ecosystem; and third, on the genetic level, it can be used help to preserve the genetic material held by both other levels (Ruderon, 1997)19. Natural landscaping, therefore, not only helps improve and increase the vertical and horizontal landscape structures needed to create appropriate habitat for small mammals, birds and insects, but it can be used to create specialized habitats and to restore existing remnant landscapes (Burrell, 1997).

From a landscape ecology perspective, landscape structure, that is, the kinds, extent, and spatial arrangement of ecosystems within a geographic area, has a critical influence on biodiversity (Romme in Nassauer, 1997). Natural landscaping can be used to create various habitat patches in the urban, built form matrix20. Through proper planning and a dedicated landscape restoration program, conventionally maintained areas could be naturally landscaped to create patches that could then be connected to each other, again through landscape conversions, to form a coherent network of patches or a natural areas matrix. Connections among more than two patches in the landscape play a critical role in biodiversity, both for maintaining viable populations of desirable native species and for spreading disturbance and undesirable species.

By actively converting appropriate areas through natural landscaping, therefore, biodiversity corridors could be created to connect with larger natural areas within and on the outskirts of the city. Where possible, remnant natural areas such as creeks, ravines and escarpments could be ecologically enhanced and protected by buffering them with a naturally landscaped area (Burrell, 1997; Ruderon, 1997; Benson, 1995). These areas could also be connected to the larger natural grid. Naturalized roadsides, boulevards, and medians could be used to create many of the linear, connective segments.

Ultimately, considering the amount of land that could be converted through the application of natural landscaping (see Section 2.1.2.1), a comprehensive network of patches and corridors could be created to facilitate species movement in and through cities. Conceivably, and optimistically, the scope of this network could be such that natural areas become the matrix and the built form the patches. Ultimately, it is just such a matrix inversion that represents the end goal of natural landscaping.

Improved Water Quality

Pre-development landscapes were the key regulators of the terrestrial elements of the hydrological cycle, controlling groundwater infiltration rates, surface water flows and overall water quality. Although urbanization has forever altered this dynamic, natural landscaping can help restore certain features and aid overall urban water quality. Indeed, the environmental benefits of naturalization in terms of water conservation, treatment and regulation is now widely appreciated and accepted in Europe and North America (Goode, 1997). ing202.jpg (42161 bytes)Native plantings are used increasingly in storm water detention, retention and interception areas to enhance groundwater infiltration, reduce downstream flooding effects and help with the removal of certain storm-water pollutants (Northeastern Illinois Planning Commission, 1997). Complex wetland communities can also be developed with excellent biofiltration capabilities to improve overall water quality. Even in areas of poorly drained soils, the permeability of a naturally landscaped area
Figure 2.2 Creek Restoration, Before
(source: EPA, 1997)
ing203.jpg (39341 bytes) is proportionately higher than that of conventionally turfed area and can thereby help reduce storm water run off (Hough 1995). With their extensive root systems, naturally vegetated landscapes hold hold soil well and can also help control erosion on steep slopes, stream banks and areas prone to overland flows. Some mature native species have 1.5 to 3.5 metre root systems compared with 10 to 15 centimetre root systems common amongst most exotic turf grasses.

Figure 2.3 Creek Restoration, After
(source: EPA, 1997)

Improved Air Quality

Natural landscaping can improve local air quality through reduced mowing needs which limits the use of gasoline fuelled lawn maintenance equipment such as lawn mowers, weed whackers, leaf blowers, and the significant emissions for which they are responsible. The reduced need for lawn maintenance also results in less noise pollution from the associated equipment such as lawn mowers and gas shears. Additionally, native plants are better able than their conventionally maintained counterparts to remove both particulate matter and carbon dioxide (CO2) from the air (Hough, 1995). Although trees have greater surface areas and are more effective at removing CO2 and particulates, native grasses, shrubs and wildflowers are still significantly more effective carbon sinks than traditional mown grass landscapes given their greater surface areas and more extensive root systems.

Improved Climate

Complex plant communities possess many qualities which make them better climate moderators than simple conventional landscapes. Depending on the type of landscape created (e.g., wetland, short grass prairie, etc.), their placement and design, naturalized landscapes can achieve the following benefits with far less cost and without the environmental impacts associated with conventional landscaping designed to do the same: the reduction of ground level wind velocities by a factor of 10; the absorption of up to 90% of incoming solar radiation, thereby cooling the immediate environment; the reduction of atmospheric particulate matter which otherwise retards both the outflow of heat from urban areas and incoming sunlight and heat energy; the reduction of winter drifting and improvement in visibility from blowing snow through natural snow fencing; and the reduction of buildings summer cooling and winter heating needs through shading and transpiration (Hough, 1995; Northeastern Illinois Planning Commission, 1997; Granger, 1989).

2.2.2 Societal and Educational Benefits

In the end, we will conserve only what we love, we will love only what we understand, and we will understand only what we are taught. Baba Dioum (quoted in Rappaport, 1998, p15)

The well known words of Sengalese conservationist Baba Dioum have a special meaning for the natural landscaping movement. As laid out in both this thesis's introduction and in Section 2.1.2.3, natural landscapes possess both environmental and educational value. With the sort of active interpretation and/or environmental programming commonly attached to schoolground naturalization projects, both private and publicly maintained natural landscapes can teach as well.

As a concept, natural landscaping is not only about incrementally improving the urban environment and reducing maintenance budgets. It is also a part of a larger exercise to improve and educate the human spirit. As numerous environmental policy papers acknowledge, to change, or improve the health of the environment, we must change. This sentiment is echoed by a special report on the ecological health of Canadian cities prepared for the Canada Mortgage and Housing Corporation by the Canadian Federation of Municipalities which states:

The establishment of a sense of stewardship...is critical if individuals are to be persuaded to adopt many of the behavioural and attitudinal changes required to establish ecological cities.(CMHC, 1995, p59)

Natural landscaping is intended to help facilitate that sense of stewardship by teaching urban and suburban dwellers to see, understand, love and conserve the complex ecological processes and dynamics that are represented in natural landscapes rather ordinary outward forms.

To be sure then, in comparison with traditional urban landscapes, naturalized urban landscapes offer profound and fundamental societal and educational benefits. Scientifically, these benefits are now being studied and documented and an increasing body of evidence suggests that naturalized areas within an urban setting can provide psychological and emotional well-being, meet a diversity of educational needs, foster a deeper understanding of and appreciation for local biodiversity, and promote community stewardship of natural resources Nature Conservancy Council, 1987; Hough, 1995; Granger, 1989; Northeastern Illinois Planning Commission 1997). Additionally, many studies have now confirmed that the contact with wildlife one can expect in a naturalized area can be a stimulating, valuable and memorable educational experience, particularly for children, to learn about the natural world and human interactions with it (Granger, 1989; Hough, 1990 and 1995; Platt et al. 1994; Nassauer et al. 1997; Nature Conservancy Council, 1987).

As inherently dynamic and engaging places, natural landscapes can provide both formal and informal opportunities for education either through their active or passive use. Formally, natural areas can provide engaging field laboratories for biology, geography, planning and environmental studies and can ing204.jpg (55735 bytes)be used by students, professionals and amateurs equally as well (Nature Conservancy Council, 1987). Many existing urban naturalization sites across both Canada and the US currently incorporate nature walks, talks, exhibits, and community forums into their structure. Indeed, the development of most projects to date have typically involved local schools and community groups in both the establishment of the area and its ongoing stewardship.

Figure 2.4 Urban Wetland/Outdoor Classroom
(source: Chicago GreenCorps, 1996)

2.2.3 Recreational Benefits

When the pioneering City of North York first embarked upon its park and open space naturalization programme in the mid 1980s, it conducted several recreational needs surveys and audited several Federal and Provincial studies on the subject. The conclusions they drew from their work was that the passive recreational needs were not being met through conventional parkland maintenance practices (Granger, 1986). The surveys and studies cut across age and income lines and determined that many of the most common activities Canadians enjoyed, such as walking, biking, and running/jogging, could be easily, if not better, accommodated in a parks system that offered a diversity of settings, both maintained and naturalized (Granger, 1986, 1989).

Further studies confirmed that the availability of areas in which to perform such activities was one of the most important ways of encouraging an individual to begin, or to continue, to participate in unorganized, spontaneous activity (Morley, 1988). A recent planning exercise conducted for the former City of Halifax, The Halifax Parkland Strategy, in fact, confirmed the need to provide for low intensity, non-competitive outdoor recreation. It is the demand for passive activities which is new, the report concluded, and must therefore form the cutting edge for changes to parkland and recreation policy (City of Halifax, 1996).

As most open space planners will agree, a diversity of needs should be met by urban parks and greenspaces. Walking, cycling, jogging, bird watching, wilding (the collecting of edible wild plants), picnics, and, of course, nature appreciation can all be accommodated in a naturalized landscape. Current design standards permit a limited palette of activities to take place and ignore the passive and active recreational benefits of naturalized areas.

2.2.4 Economic benefits

As outlined in Section 2.1.2.2, conventionally maintained parks, gardens and formal open spaces are very expensive and time consuming to maintain. Comparatively, the cost savings with naturalized landscapes are significant and, in fact, quite often make them the cheapest management option for both publicly and privately maintained properties (Goode, 1997). Naturalized landscapes are not maintenance free, but the bulk of their costs are contained in the first three years of establishment, after which point general maintenance is usually reserved for an annual mowing or prescribed burn21. Costs also vary according to the type of landscape development, as some communities such as wetlands, for example, are more expensive to create and/or restore. With any type of naturalized landscape, however, site preparation, plant materials and preliminary labour consume the largest portion of the initial budget, while weeding, typically by hand, during the establishment years is the second most time and cost consuming. Still, all things considered, their development costs compare favourably to conventionally sodded and/or seeded landscapes (Northeastern Illinois Planning Commission 1997, EPA, 1998). Additionally, given their reduced maintenance needs, both individuals and public authorities can realize the savings associated with reduced gas consumption and wear and tear on equipment.

One key cost determinant is the type of management approach taken. Naturalized landscapes can be developed by simply halting maintenance and letting natural succession occur. Over time, the turf grass associations are replaced by native and naturalized plants22. Succession landscapes can, especially from turf grass, take a very long time to develop, however, and do not provide the more immediate aesthetic rewards that an actively developed naturalized landscape can create.

The monetary savings associated with natural landscapes can best be appreciated, however, in extended management scenarios. Comprehensive studies conducted by the EPA and the Northeastern Illinois Planning Commission determined that 80% to 90% cost savings could be expected over a five to ten year cost comparison with conventionally managed and cultivated landscapes (EPA, 1997; Northeastern Illinois Planning Commission, 1997). Canadian cost comparisons are in the same range (personal contact, City of Toronto, Metro Parks and Culture, 1998; City of Guelph, Recreation of Parks and Recreation, 1998; District of West Vancouver, Parks Department, 1998). The original installation costs can also be reduced where the project sponsor has native plant propagating capabilities, as the majority of nurseries do not carry them. The table below is taken from an EPA cost comparison study. More cost information can be found in Appendix 1.

Table 2.1 Native Landscape Treatment Costs (1995 US $ cost per acre)ing-T201.gif (160366 bytes)

(source: Applied Ecological Applications Service in Northeastern Illinois Planning Commission, 1997)

2.2.5 Applications and Limitations

Natural landscaping is not a panacea for urban environmental problems. Although the concept embraces a range of opportunities for property owners, grounds managers and public officials it cannot, and should not, be applied indiscriminately to all situations, or, as Michael Hough points out, it becomes another doctrine...tarred with the same brush that inspire our current pedigree urban landscapes (Hough, 1990, p190). The following two sub-sections outline some of the practical, non-policy related, limitations and applications of natural landscaping in urban and suburban locations.

Limitations

Unlike the instant landscapes created by laying sod and planting one or two trees, natural areas created through natural landscaping can take time. This is very important point, as it represents a potential stumbling block for any municipality or private individual seeking to adopt a natural landscaping program or strategy. Basically, natural landscapes take time to establish themselves (typically three to four years); they take time for public authorities and private property owners to educate and convince others of their environmental importance, societal value and aesthetic beauty; they take time to be maintained even after their establishment with perimeter maintenance, litter removal and/or weeding when necessary; and, most importantly, they take time on the part of the responsible authority to learn and understand their internal structures and dynamics. Unlike lawn monocultures, the ecology of naturally landscaped areas is complex and time consuming for practitioners to understand. As Sara Stein rather poetically writes in her book Noah's Garden: Restoring the Ecology of Our Own Backyards, about her experience naturally landscaping her suburban property:

Prairies don't come in a mix, like seed: they can't be put in backward: orchids before grass, climax species before the pioneers. Subtle ingredients must be added bit by bit, one species summoning a fungus that makes an antibiotic that is needed by another species that then calls to its petals its vanished pollinator. ...It is not easy.(Stein, 1993 p 156)

Natural landscaping in urbanized areas is still in its infancy and without a very large body of supporting scientific research and documentation. For most people involved in natural landscaping projects, therefore, the process experiences can perhaps be best summed up by a comment made by Chicago's Assistant Commissioner for the Department of Environment concerning one of the city's boulevard naturalization projects: It's a landscape in evolution (personal contact, January 1998).

Natural landscapes represent very small ecological islands in an overwhelmingly urban, built form matrix with many unique stresses, human impacts and limiting factors. The interrelationships between the site and the matrix, the urban ecology, is so complex and represents such a new field of study that often it is not known how the reintroduced natural landscape as a whole, and its individual species, will fare (Reed, 1994). Often, projects fail to reproduce site conditions or to integrate the communities found in nature. At other times, the soils and micro-climate associations have conspired against certain native species establishment. Although some public authorities, notably Metro Toronto Parks Department, have excellent monitoring programs in place, most would concede that it will be some time before they can develop sure-fire planting strategies (personal contact, Toronto Metro Parks and Culture, 1998).

In addition to scientific limitations, the adoption and application of natural landscaping strategies also requires the development of fairly comprehensive site selection guidelines. Natural landscaping can not and should not be applied haphazardly. For it to be truly successful, appropriate sites should be selected using a matrix approach that takes into account biotic and abiotic values, including heritage and cultural values. Halifax's Victorian-style Public Gardens, for instance, may not be a candidate for naturalization given its significant historic, cultural and tourism values.

Additionally, it is imperative the public be involved throughout the site selection and site development process. Likewise, private property owners should advise and consult neighbours about their smaller projects. Public involvement is crucial to the success of any small or large scale undertaking. Neighbours and the general public should have an idea of the concept and the process of natural landscaping, so as not to be left with the impression that a persons front yard or public park area is simply being abandoned to weeds. Public and private projects must reflect human involvement, intention and direction, or perceived care as one author refers to it (Nassauer, 1997)23. When human care appears absent from a project, or when neighbours and the public are not advised or involved, the results can be disastrous for the natural landscaper. There have been cases in Guelph, Ontario, for instance, where public mowing regimes were halted in certain boulevard areas to permit a successional habitat restoration. The restoration effort was stymied by local residents and business owners who mowed the boulevards themselves. The residents involved were either unaware of the city's motives and convinced that they were actually helping out, or they were motivated out of frustration and anger, believing that that city was neglecting its maintenance duties (City of Guelph, personal contact, January 1998).

ing205.jpg (64000 bytes)Figure 2.5

Perceived Care


From pretty pond to neglected puddle. With the addition of a few pieces of litter perceptions can be altered.

(source: Hough, 1990, p 192)

Ultimately, it is the goal of natural landscaping to expand traditional, aesthetic cultural values to include the ecological, or messy, aesthetics of native landscapes. As a process, natural landscaping therefore consciously seeks to expand the cultural expectations associated with the urban landscape by incorporating the apparent disorder of indigenous systems within the reassuring visual framework of human presence (Nassauer, 1997).

Applications

Natural landscaping can be used by public officials and private citizens in a variety of situations. Bearing in mind its practical limitations, it can be employed within new landscape developments, to convert older, traditionally maintained landscapes and to help restore, enhance and connect remnant pockets of urban wilderness, such as those commonly found in ravines, escarpments and along some water courses.

Natural Landscaping for Public Officials: a Source Book, a joint publication of the Northeastern Illinois Planning Commission and the US Environmental Protection Agency, outlines some examples of where natural landscaping can be used. Although it is by no means a complete list, it nevertheless suggests the number of ways natural landscaping can be used. An excerpt from their list follows.


Table 2.2 Overview of Natural Landscaping Applications

New development of all types can:

Existing institutional and commercial complexes can:

Individuals and groups of homeowners can:

Local governmental units can:

(source: Northeastern Illinois Planning Commission, 1997)


ing206.gif (28864 bytes)Figure 2.6

Park Applications

The open turf area in this urban park is a source of cool air that is carried into the surrounding area by prevailing breezes. Naturalized buffer plantings along the park boundary reflect the complex structure of the regions native plant associations. For a discussion on the associated climatological benefits of natural landscaping see section 2.2.1.

(source: Platt et al., 1994)

ing207.gif (28477 bytes)Figure 2.7

Streetside Applications

Reclaimed greenspaces along residential streets provide areas for naturalistic plantings that enhance biodiversity by creating riparian-like habitats. Runoff harvested from the streets and sidewalks reduces flooding downstream and conserves irrigation water. Small trees that use little water shade nearby buildings. For a discussion on natural landscaping's climactic and hydrological benefits see section 2.2.1.

(source: Platt et al., 1994)

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