Nature on the side of the road :
The case of community gardens in the greater Grenoble area
This research deals with the roadsides and rail-sides’ community gardens. They are the consequences of a layering urban development from which noteworthy “ambience shocks” emerge. The purpose of this unexpected cohabitation’s study is to evaluate the mitigating roles of transport infrastructures’ community gardens within the present and future territories. In other words, is it possible to design a sustainable roads and railways network that could shelter an infrastructure-side nature with a social and ecological vocation?
Approaching the territorial scale of the green urban frame as well as the local scale of dwelling, we tried to give answers to this question by crossing, theoretically and methologically, the knowledge of ambiances, urban design and ecology. Five town property and illegal community gardens and six “feral”1 grounded spaces, located along the road and/or the railway and often linked to social housing have been studied through this crossed approach at Echirolles and Saint Martin d’Hères cities (France, Rhône-Alpes department).
At the scale of gardens and feral spaces, a method to cross the ambience and the ecological criteria bas been set in order to question and define analysis and design criteria. With the focus on dwelling, garden ambience units have been revealed through ethnographic observations, sound recordings and Leq sound level measures within and around the gardens. These ambience units link social interactions, urban settings morphologies and sensory (sound, light and climate) qualities. On the garden plot, gardening and social practices are linked and their influence on biodiversity evaluated. From the ecological point of view, a wild fauna and flora inventory have been realized and ecosystemic formations characterized in order to evaluate the local biodiversity (species diversity) friendly contribution. Gardens’ biodiversity is ordinary but otherwise interesting.
At a larger scale, functional ecology is approached through green urban frame in order to evaluate the gardens and feral roadsides’ role of reinforcement of this frame. Finally the crossed questionings have been debate with experts (chemists, ecology engineers, gardens’ developers and managers, transport infrastructures designers) and municipality actors. Thus, on the feral roadsides, scenarii transformation has been explored in order to question the development of gardens on them through the twofold approach: ambience and ecology.>
Our results show that roadsided gardens and feral roadsides contribute to distend the ecological continuities that are along the roads and railways. In terms of experienced ambiences, those gardens create distinctive places allowing dwellers as well as walkers to escape momentarily the sound and visual annoyances of the road and the railway.
The collaboration between the ecological subject and the urban design subject requires the creation of criteria adjusted to particular socialization spaces, promenade spaces and grounded spaces. These criteria are both a goal and a means to understand these multiform, complex and paradoxical situations and to consider a more sustainable way to design transport infrastructures fitted in the urban territory. Otherwise, some obstacles to the roadside and rail-side gardens and to their integration within the green and social frame appear and require more scientific investigations (especially in terms of air and soil pollution) as well as the continuation of the dialogue with the institutional actors.