Places for People, Places for Plants Evolving Thoughts on Continuous Productive Urban Landscape.doc

places for people, places for plants: evolving thoughts on continuous productive urban landscapea. viljoen1, k. bohn2, m. tomkins1, and g. denny3.1 university of brighton, mithras house, school of architecture and design, faculty of arts and architecture, lewes road, brighton bn2 4at, uk.2bohn & viljoen architects, 18 copleston road, london se15 4ad.3 university of cambridge, department of architecture, faculty of architecture and history of art, 1-5 scroope terrace, cambridge cb2 1pxkeywords: cpul, urban agriculture, architecture, sustainable urban design, food miles, greenhouse gas emissions, allotments, behaviour change, embodied desire, desire-in-useabstractthis paper reviews the role of urban agriculture within the context of the continuous productive urban landscape (cpul) design concept. cpul proposes a coherent strategy for the introduction of interlinked productive landscapes into cities thereby creating a new sustainable urban infrastructure. the paper focuses on urban agriculture as one of the major components of cpul. making reference to recent high-profile international exhibitions and publications, the paper traces urban agricultures remarkable shift from a fringe interest to one at the centre of contemporary urban/architectural discourse. the paper discusses examples of recent and emerging research with respect to greenhouse gas emissions, behaviour change and urban design, to further inform our understanding of the potential impact of cpul and urban agriculture on the city. the paper concludes that, while urban agriculture is receiving a great deal of attention, the theory underpinning its design and the rationale for developing policy to support its practice will require sophisticated cross-disciplinary research to reacharticulate the concepts full potential as an element of essential infrastructure within future sustainable cities. the case for cpul has to be made by taking into consideration multi-faceted and cross-disciplinary arguments, which collectively provide strong evidence in support offor cpul and urban agriculture. introduction - a cpul overviewcontinuous productive urban landscape (cpul) is a design concept advocating the coherent introduction of interlinked productive landscapes , notably urban agriculture, into cities as an essential element of sustainable urban infrastructure. central to the cpul concept is the creation of multi-functional open urban space networks that complement and support the built environment (fig.1). the conceptit grew out of design research exploring the role of urban agriculture within urban design , was first articulated in 1998 (viljoen and tardiveau, 1998), and was first designed for in 1998 (bohn&viljoen architects) and then definedfirst defined by bohn and viljoen architects respectively in 1998 and in 2005 (viljoen a. 2005). central to the cpul concept is the creation of networks of multi-functional open urban spaces for productive daily use that complement and support the built environment (fig.1). key features of cpul space include productive urban landscapes, in particular urban agriculture, outdoor spaces for people, natural habitats, wildlife and circulation networks for public and non-vehicular traffic (fig.2). the cpul network connects existing open urban spaces, maintaining and in some cases modifying their current use and forming ecological corridors. cpul impacts on the city qualitatively with respect to citizens experience and quantifiably with respect to reduced negative environmental impact (viljoen a. 2005).the concept recognises that each site and city will present a unique set of conditions and competing pressures informing the final shape and extent of the cpul (fig. 3).within the cpul concept, urban agriculture refers in the main to fruit and vegetable production. typical urban agriculture practice ranges from small scale “food gardening” to high yield, space-efficient urban market gardening. urban agriculture is inherently suitable for inclusion in localized zero-waste systems, whereby composting can be used to reduce waste (drechsel and kunze 2002).the cpul design concept is underpinned by a number of robust and interrelated social, environmental and economic arguments for what would amount to a radical change in the configuration and programming of open urban space within an overarching desire to find more self-sustaining ways of living. greenhouse gas emission reduction, peak oil data, and increasing urbanisation all contribute to and challenge the concept.for urban agriculture, a solid body of literature exists describing its social impact with respect to food security, to development policy and the positive social impact of urban agriculture in places with high indices of social deprivation (egziabher et al. 1994; koc et al. 1999; caridad cruz and snchez medina 2003; mougeot 2005; van veenhuizen 2006). other areas of research relevant to cpul are just starting to appear: academic research assessing the impact of green space in the urban environment with respect to human well-being is beginning to be disseminated, as evidenced by presentations at the 2nd international conference on urban landscape and horticulture 2009. in great britain, with the exception of work on localization undertaken by the new economics foundation, research relevant to the economic viability of urban agriculture remains rare; this is a subject area where new research is essential. during the late 1990ies, it was similarly difficult within great britain to access detailed contemporary studies into the embodied energy and associated greenhouse gas emissions of foodstuffs. in recent years, a number of studies have helped address all these concern, and will be discussed below. within design disciplines, the dissemination of new ideas takes place as much through the medium of exhibitions as through the publication of academic papers. in theseis disciplines, a rapid increase in interest, exploration and dissemination of ideas about designing urban space for urban agriculture is evident. figure 4 records, from the perspective of the cpul concept, the relationship between a number of organisations, researchers and key publication advocating, testing and developing urban agriculture. two organisations with a strong web presence, city farmer () and ruaf () have provided a long-standing resource for activists and researchers, each broadly addressing a different constituency with city farmer providing community/activist support and ruaf addressing issues related to urban poverty and development. the publication in 1996 of the book “urban agriculture: food, jobs and security” (smit j. 1996) was a landmark in defining an international role for urban agriculture and may be considered seminal to a sequence of publications, academic and popular. while planning for urban agriculture has already been on the agenda, the publication in 2005 of “cpuls” (viljoen a. 2005) was the first time a book was devoted to presenting a design strategy for the coherent integration of urban agriculture into cities. a further milestone in the exploration of design consequences and possibilities arising from urban agriculture was reached in 2007, when the netherlands architecture institute (nai) maastricht curated an exhibition titled “die eedbare stad / the edible city. this brought together an international group of leading architects and artists all, at that time, exploring urban agriculture within their work. since then, the number of similar exhibitions and “public works” hosted by leading international design institutions has continued to increase and includes the uk design council led dott 07 urban farming project in middlesbrough (2006/07), the canadian centre for architectures exhibition actions: what you can do with the city (2008), the vertical farming exhibition at exit art, new york (2009) and the dutch art organisation strooms foodprint programme commencing in june 2009 in the city of den haag.these activities are likely responsible for urban agriculture and cpul beginning to be integrated into planning policy within the uk. evidence for this can be found in the greater london authoritys / design for londons proposals for the “green grid”, a network of open spaces within the city integrating significantly amounts ofincluding provision for productive landscapes (bldgblog, 2009). concurrently, the greater london authoritys planning and housing committee is planning to undertakundertakinge an investigation into the role of the planning systems role in supporting and encouraging commercial food growing in london (jones j., pers. commun. 2009).notwithstanding these developments, the publication, “agriculture in urban planning” (redwood 2009) concludes that architects and planners require further “awareness of and sensitivity to including “green” and agricultural features into the design process”.for discussion: new and emerging research ghg emissions and urban agricultureurban agriculture has the unique potential to reduce ghg emissions by reducing the energy use required to transport food from source to consumer. the various reports on greenhouse gas emissions indicate the variety of studies undertaken and that these often use different categorisations and measures of environmental impact. for practitioners in the fields of urban and landscape design, accessing and contextualizing this information impact is not always straightforward.within the united kingdom, a detailed study of food miles was published in 2005 (defra 2005). this report noted that, in total, food transport in the uk produced 19mt of carbon dioxide in 2002 of which 10mt were emitted in the uk, and that the food chain was responsible for 17% of uk greenhouse gas emissions. in 2008, a report commissioned by the greater london authority assessed the greenhouse gas emissions associated with londons food sector and concluded that transport, storage and distribution accounted for 19% (3.6 mt co2 e/yr) of londons food related ghg emissions, while primary production and manufacture of food accounted for 59% (11 mt co2 e/yr) (brook lyndhurst 2008). the report also noted that the european commission estimated that 31% of european union consumption emissions are food related (european commission 2006).a recent study from the usa (weber et al. 2008) contextualises the relative impacts of a localized food supply system with respect to food type and degree of processing and manufacture. weber et al. used input/output life cycle analysis to assess the ghg emissions associated with food production and supply chains for the usa which is, like in many industrialised countries, dominated by remote industrialized production methods. weber et al.s study categorised ghg emissions by food type and production stage and concluded that, on average, transportation represented 11% and the production phase 83% of life-cycle ghg emissions. the study shows that a majority of foods climate impact is due to non-carbon-dioxide emissions, mainly due to nitrogen fertilizer application, other soil management techniques and manure management. while these non-carbon-dioxide impacts are found in all food sources, they are especially concentrated relative toin meat and dairy production. weber et al. conclude that “a dietary shift can be a more effective means of lowering an average households food-related climate footprint than “buying local.” shifting less than one-day-per-weeks worth of calories from red meat and dairy products to chicken, fish, eggs, or a vegetable-based diet achieves more ghg reduction than buying all locally sourced food” (weber et al. 2008, pp3508). if it is accepted, then weber et al.s paper shows that fruit and vegetables have the second highest ghg emissions impact per household and the highest ghg transport impac (weber et al. 2008, fig 1 pp3510). this conclusion makes it clear that urban agriculture cannot be viewed or assessed in isolation, and only makes sense from a ghg emissions standpoint if it is seen as part of a general behaviour shift that includes a reduction in the consumption of meat and dairy products. if it is accepted that meat and dairy product consumption should be reduced, then disregarding their impact, weber et al.s paper shows that fruit and vegetables have the second highest ghg emissions impact per household, and furthermore they have the highest ghg transport impact. (weber et al., 2008 fig 1 pp 3510). all reports in ghg emissions in relation to food confirm that urban agriculture cannot be viewed or assessed in isolation and only makes sense, if it is seen as part of a general behaviour shift. in a “low carbon” economy and one that attempts to reduce energy consumption, a valid case can be made for urban agriculture, in particular when it integrates waste minimization techniques, such as composting, or the minimising of heating/refrigeration during the growing or storage process. this requires the careful selection of production and processing systems and their integration into the urban infrastructure and food supply systems, if savings due to reduced transport are not to be eliminated by energy use elsewhere.such a conclusion does not come as a great surprise, as, after all, historic arguments made prior to the petro-chemical era provide evidence for the advantages of locating fruit and vegetable production adjacent to urban areas. the writings of johann von thnen (chisholm 1972), in particular, deserve revaluation. behaviour change potential of urban agricultureat another scale, that of the individual non commercial grower, evidence is emerging for behaviour change potential related to food growing. in the uk, the allotment has shown itself to be a catalyst for changes related to diet and health. surveys undertaken by one of the authors, denny, within cambridge and middlesbrough, reveal the allotments continuing influence across all socio-economic ranges. most notable are a substantial increase in the quality and quantity of food being consumed by allotment gardeners during the growing-season, and decreased dependency on grocery stores as a source for fresh produce: 70% in growing-seasons and 24% during the off-season. changes in food-miles reduced personal carbon emissions by an average of 950 kg co2/year, even while still predominantly utilizing grocery stores during off-season months and maintaining an overall dependence on fossil fuelled transport year round. allotment tenants also surpass the recommended 30 minutes/day of daily activity, through time spent within the allotment itself and through active-commuting related to food procurement. furthermore allotment holders who ate less than the recommended daily intake of fruit and vegetables before they had an allotment, increased their fruit and vegetable intake once they started growing food, and this increase was reflected in an increased proportion of fruit and vegetables purchased thought the year. if this trend is validated in further research, it will indicate the significant behaviour change impact that may be attributed to even relatively modest urban agriculture interventions.the croydon experiment: ideas for using the city as a laboratorycroydon is a borough of greater london covering 88,064 sq km, often characterised by post war large-scale office blocks, multi-storey car parks and road developments. the croydon experiment was set up by tomkins in 2009 to explore the relationship between how individuals practice urban agriculture at a small scale and the design and form of contemporary urban space. the authors were interested in the evident contradictions between the often opportunistic way people grow food in cities, and the formal layout of towns and cities. .the research work undertaken in croydon looks at a 25 ha test site to the west of its well-established fruit and vegetable market on surrey street. research into croydons potential to grow food locally suggests that the markets position within the town centre could be exploited as part of a network in support of ua. the experiment addressed two questions, firstly how viable is roof top food growing within an urban environment and secondly what type of growing (commercial or individual / community based) would be most appropriate for this location?rthe research projects began with an analysis of the underlying physical urban geography, where all suitable horizontal food growing areas where mapped for their potential to grow food. this analysis showed that 7.25 ha of the 25 ha site where suitable for food growing. interestingly, the majority of this (4.25ha) is accounted for by the roof top space including two multi storey car-park roofs. using potential yields of 31 tonnes a hectare, the site is potential a net exporter of 43.65 tonnes of vegetables for the test sites 1425 residents. the activity of food growing within the built environment is often undertaken as a contradictory activity, not envisioned by the original architects and designers. residents ability to adopt post-occupancy activities of altering or transgressing is clearly evident in public parks and open space. here we commonly witness many user defined pathways or “desire-lines” that criss-cross the grassed areas often ignoring the tarmac pathways laid down by urban and landscape designers. another way of critically analysing this is to consider the original design as having embodied-desire (the desire to keep people off grassed areas literally “embodied” in tarmac) and the users desire-lines as evidence of desire-in-use (the incremental everyday activity of a preferred walking path from a to b).in 2008, this critical and somewhat philosophical thinking was tested within the 25ha test site in central croydon. a visualisation too