THEORETICAL CONTENT

The transformation of cities into self-sustainable environments can not only depend on the introduction of eco-technologies. A social commitment for sustainability is needed. This commitment can be reached through collective participation, social debate, and educational diffusion. Urban agriculture is an ecological farming that occurs within the city. It allows growing food for local consumption, managed by the local community, renting the land to the municipality for private use or for commercial purposes inside the same local framework. The market and consumption of food (vegetables and fruit) is seasonal and organic. Increases biodiversity inside the city, reduces atmospheric pollution, saves energy consumption in transportation. However, urban agriculture will never be self-sufficient to sustain the alimentary needs of a city. Despite this fact, urban agriculture allows a social interaction with the environment based in a close physical experience, helping to educate new generations, introducing new sustainable habits, especially beneficial for elderly, facilitating social and cultural cohesion, based on the principle of ecological awareness. André Viljoen and katrin Bohn introduced in 2005, the concept of "Continuous Productive Urban Landscapes" (CPULS) as the proposition of a new urban design strategy, based on a continuous landscape inside cities. CPULS are open spaces running the city transversally, as a continuously carpet through the built urban environment, connecting all kind of open spaces, covering the urban tissue (including roofs of buildings), without erasing its qualities. This continuous landscape, depending on the setting, can be a park, a forest, or spaces for urban agriculture, managed to be environmentally and economically productive, providing food for the close communities, establishing a healthy and sustainable balance of production and consumption. These continuous productive landscapes may change the lifestyle of people, facilitating connectivity inside cities, working and leisure habits (A. Vijoen, K.Bohn, 2005).

Urban parks, green open areas or any uncertain spaces in the city (empty vacant spaces, old buildings, brownfields, spaces left aside of urbanization) have the potential to become productive landscapes, green engines that provide resources (energy, rainwater recycling, seasonal ecological food) to the close neighborhood, self-maintained by processes of communal self-organization. Independently of their connectivity inside the city, these green engines are green islands, self-sustainable urban agro-ecosystems. Processes of transformation and change inside the city can come from bottom up, from people making the city. According to Complexity Science and Self-organization theories (Manson 2001; O'Sullivan 2004), self-organization is an autonomous action, based on complex and uncertain relationships happening between organizations and individuals. The individuals play a role in the creation of urban space and they have the potential to reflect and respond critically to their environment and develop themselves through learning. A landscape planning strategy establishes those designed actions that will trigger processes of change and social involvement with the environment. In this way there is an interaction between the formal and the informal planning, appearing a complex system that evolves over time with new stages that are not predictable by a linear causality but by a circular one that is constantly readapting.

A CASE STUDY: TRES TURONS PARK

The area of "Tres Turons" (includes the hills of Creueat del Coll, Carmel, and La Rovira) is a strategic green space in the northern part of the city of Barcelona, and because of its orographic characteristics, it is a unique balcony to the city, with great environmental, historical and social values. Inside the area, there are three consolidated parks: Park Güell, part of the UNESCO world heritage, designed by Antoni Gaudí, Park La Creuta del Coll, and Guinardó Park by Jean-Claude-Nicolas Forestier, together with small gardens. The original landscape of the hills, once agro-forest, has been transformed by the human activity, containing old quarries, an anti-aircraft civil war battery, and informal urban occupation of self-constructed settlements during the post-war rural migrations, together with shanties, wastelands and sightseeing public platforms. The urban fabric surrounded this open area is dense and intensive populated without any planning, mainly by self-constructed houses, and later real estate developments, creating a mixing of different construction typologies. The Modification of the Metropolitan Master Plan, approved in January 2009, consolidates the space of 122 ha in Tres Turons, in its majority of public ownership, as a Park with a green area of 94 ha. The Master Plan for the new urban Park includes the demolition of illegal constructions, mainly in the top of the hills, and the resettlement of the existing inhabitants to new housing areas in the perimeter of the area. One of the main objectives of the Plan is the reinforcement of the perimeter of the park to revitalize the neighbourhoods; therefore, new facilities will be built around it. However, this Master Plan faces a big social opposition of the neighbours, because since 2004, the neighbourhood bodies propose a counterproposal, showing that the park is capable of meeting its objectives and respecting at the same time a mixed structure of housing and green spaces.

INTERDISCIPLINAR APPROACH

In this first decade of the twenty first century, and due to the increased awareness in ecological and environmental concerns, scholars, architects, urban planners and landscape architects became involved in the emergence of a new hybrid practice, involving urban planning and landscape. This new practice and discipline was anticipated in the Symposium "Landscape Urbanism" in 1997, organized by Charles Waldheim. Later, he, as an editor, collected essays by practitioners in all the mentioned disciplines, in the book Landscape Urbanism Reader (2006). Especially James Corner's article, "Terra Fluxus" (2006), outlines the qualities of this new practice. First, it considers urban processes over time, second anticipates strategic scenarios and operational logics through a wide range of scales, third reconsiders representational and operative techniques, and fourth takes in account the phenomenal richness of physical life (social imaginary, collective memory, desires, the tactile and the poetic). The new practice of Landscape Urbanism has been experimented in postgraduate courses at the Architectural Association since 2004, centered in the representation of time-based urban processes using new representational techniques by visual modeling, and malleable graphics. It has also been discussed in roundtables and workshops, like in the Colloquium "Articulating Landscape Urbanism" organized by the Chair of Landscape Architecture in Wageningen University in 2007. Recently, the Conference at Harvard University Graduate School of Design, "Ecological Urbanism: Alternative and Sustainable Cities of the Future" in April 2009, aimed to point issues surrounding the sustainability of the city, recognizing the need for an ecological approach to the rehabilitation of the contemporary city and an organizing principle for the development of new cities.

EDUCATIVE METHODOLOGY: RESEARCH BY DESIGN

In order to introduce the methodology of work of the practice of landscape urbanism, the students had to familiarize, in a short period of time, with an interdisciplinary approach. The students had to learn to develop a design proposal that was not shaping a predictable form for the future of a space, but offering an alternative future. Their proposal had to be a planning strategy that took in account flexible dynamics, scenario thinking, and processes in time that relate with changes and re-adaptation. Because of the short period of time to develop the work, we made clear that we were not interested in the excellence of the proposal representation but in the ideas, and the learning by dialogue. The students were concentrated, not in their presentations, but in communicating everyday what they had discovered, using sketches, digital collages and renders. What is important in the practice of landscape urbanism is to be able to move in the surface of the area of study, as a strategic platform, with an operational logic, speaking about tactics, and how those actions produce changes in the space over time. Therefore, it was necessary that the students familiarized with the exercise of moving through different scales of work simultaneously. Going from the big picture, to the intermediate scale, and the detail of a specific designed action, n order to go again back to the big picture and tell the story from the beginning again. It is then, when the students realized that the environment was not a designed object, but a complex system of elements that create a network of interactions between them. We also insisted about another important topic, basic in the understanding of how a sustainable environment works, that is, the consideration of the qualities of a phenomenal space that is lived, looking at memories, identity, and the tactile materiality of the space.

In the Experiential Learning Theory (ELT), there are four phases. In Concrete Experience (CE) phase, learners prefer to learn by experiencing and in Reflective Observation (RO), learners have the tendency to learn by reflecting. In Abstract Conceptualization (AC), learn by thinking, through the analysis of ideas, is the preferred learning style, and in Active Experimentation (AE), learn by doing, through active experimentation, is chosen by learners (Kolb, 1984; A?kar, Akkoyunlu, 1993). The major phases that occur in the learning process of the students who participated in the workshop were stated as Concrete Experience (CE) and Abstract Conceptualization (AC). In Concrete Experience (CE), we have seen how students learned from feelings and life experiences with the contact with the real location. Therefore, they learned how they should use the environment and the current social and physical context, with sustainable, affordable and realistic solutions. Features such as learning by thinking, analysis, systematical approach, making new proposals were important in Abstract Conceptualization (AC) phase. As a consequence of this phase, they mostly improved their design skills as well as they learned ways of express ideas. The workshop was also a good environment for collaborative learning. t involved a coordinated design activity that was the result of continuous attempts to construct and maintain a shared understanding of the design problem.

WORKSHOP STRUCTURE

The workshop was structured in five parts. Each day the students were receiving a single task in order to help them to handle the complexity of moving through different scales. The idea was to learn by progress, testing day by day the results. With the analysis, the students were asked to evaluate the qualities and problems of the site, looking at the existing biodiversity and topography, infrastructure, existing public facilities and social use, character of the neighbourhood, boundaries, and definition of distinctive areas. Based on the analysis, the students were asked to find a planning strategy to implement a self-sustainable urban agro-ecosystem, looking at the improvement of accesses from the neighborhood to the site and the permeability of boundaries, allowing easy connections and a fluid circulation. The students had to take in account the time implementation of programmatic areas, clean energy-sources, water and waste recycling, community facilities, plot food garden division, preservation of biodiversity, new plantations, and the system of roads and paths. Different scenarios were tested to decide a clear strategy: education, tourism, recreation-health, community work (family and elderly oriented), young platforms for self-expression and commerce. Based on the strategy, the students were asked to elaborate a conceptual design that translated the planning strategy into a landscape atmosphere, which was experienced by the senses and the mind. Some guidelines were suggested, like Conservationist conceptual design approaches (Restoration of Croscat Volcano, Girona 1993, Martirià Figueras - Joan Font); Radical (Yverdon-les-bains, Expo 02, Switzerland, West8); Ecology - machinery (Ecoboulevard in Vallecas, Madrid 2007, Ecosistema Urbano); Market-profit oriented (Explanada Forum, Barcelona 2004, J.A. martinez lapeçna- Elias Torres); or Iconographic-emblematic (La Vilette Park, Paris 1982, Bernard Tchumi). Based on the conceptual design of the landscape, different design actions were asked to be developed in detail in order to trigger change in the site, and activate the community involvement and participation. The students were asked to think those minimum necessary actions that can improve the quality of the space, guide self-organization, and activate imagination together with the ability of the user to interact with the space. The results were abstract sections and details. With the complete landscape design proposal, the evaluation helped them to compare the results of the three groups, estimating weaknesses and strengths of each proposal and elaborating a conclusion regarding the implementation of a community self-organized agro-ecosystem in Tres Turons Park.