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Ecology and urbanism, an overview. Part 2

Where we encounter three of our heroes, Joseph Paxton, Frederick Law Olmsted and Charles Eliot, Who have introduced three crucial concepts of urban design.

Ecology and Urbanism / 2 Landscape architecture

The heroic phase of Landscape Architecture 1850-1900

In urban planning, and again in the US context, landscape designers experience, within a proto-ecological and romantic vision of nature, the integration between built and natural open spaces (Dumpelmann 2003). American landscape architecture inherits the teachings of the English and German landscape architects of the eighteenth century. It applies these teachings to the dynamic industrial world, where technological and economic development are profoundly transforming the natural landscape. Although it does not have an explicit statute or defined models, US landscape architecture is based on the idea that nature has healing properties, as argued by the founder of the discipline, Frederick Law Olmsted sr.. Olmsted introduced the idea of ​​"sanitation" to describe the relaxing effect of nature on human beings, particularly necessary in urban contexts. 19th century Landscape architecture was not an anti-urban or anti-capitalist movement but a professional activity that tried to equip itself over time and through design experiences with the tools required to design a functional and performative landscape. Olmsted identified these qualities with the English landscape: a picturesque aesthetic, mindful of the sequences of the scenarios, but at the same time based on the knowledge of local biological and hydrological processes. Capability Brown and Joseph Paxton (the Birkenhead Park in particular) were his main references. His was a proto-ecological approach that enhances the dynamism of fruition by constructing the landscape as a sequence of scenarios and uses theoretical models of ecology and forestry, such as succession and selective competition, to let natural processes select the plant species suitable for any context. In the American industrial cities, these principles are translated into new forms of integration of city and landscape, society and nature. Olmsted became the founder of the discipline when he (almost accidetally) won the competition for the design of New York's Central Park in 1858 together with Vaux. In their proposal, the park is not a natural element isolated in the mineral fabric of the dense city, but a man-made landscape, manipulated through earth movements, excavations and natural selection of plant elements, perfectly integrated in the fabric of the city. Olmsted and Vaux's design was in fact the only that solved the issue of keeping some form of connection between the two sides of the park, which would have otherwise a seprating element. Through a system of connections at different levels the design allowed the coexistence of pedestrians, horses, carriages and animals. The Park is an infrastructure that fits into the continuity of the urban fabric without interrupting its connections; on the contrary, it enhances their complexity. The multifunctionaityl of the design solution - park, infrastructure - signals the intent to integrate city and nature: finding an innovative "form" of hybrid urban natural development, in line with the needs of the expanding metropolis.

The Park System

The model of the urban park evolved into the park system: a system of interconnected open spaces that were prefigured in areas not yet reached by urban expansion; an idea that spread to major American cities, starting with the Minnesota system, designed by Horace Cleveland. The park system is a concept, rather than a fixed physical solution: on the one hand it prescribes continuity and connections between green spaces (in this sense it anticipates systems theory, interscalarity and ecological networks); on the other, it shuns rigid schemes. An important innovation of this model is the Boston Metropolitan Park System, conceived by Charles Eliot jr. (a student and later a business partner of Olmsted), The first regional plan for the protection and implementation of natural resources in relation to urban growth. Developed when the city was already among the largest in the United States, the value of the land high, few open spaces, the plan proposed to acquire the residual areas, often degraded and compromised by pedological or hydrological problems, to create punctual and linear system of open spaces for the city. A retroactive intervention strategy that sought to insert itself into the speculative development mechanisms of the American industrial city.

2.1 The Emerald Necklace and the Back Bay Fens

The project of the Emerald Necklace, designed by Frederic Law Olmsted between 1878 and 1890 (Zaitzvesky 1992), is a filament of open spaces that connects the city with the large Franklin Park on the outskirts by configuring an ecological corridor. It highlights the contractual and conflictual dimensions of the land acquisition process: linear and punctual elements of variable size and width through the marginal areas of the city. Olmsted designs the different components of the linear system by integrating hydraulic control devices, connections through parkways, and landscape design. The Back Bay fens (marshes) constituted the last ring of the system, which followed the course of the Muddy River and accompanied it until it entered the Charles River, whose flow was influenced by the ocean tides. The vast wet area of ​​the fens had been progressively reclaimed to make room for urban expansion, causing the disappearance of a landscape and a system of ecological functions of hydraulic regulation and water purification. In the second half of the century the expansion had occurred rapidly and had affected various areas of the Charles basin, where the sewage was discharged; the morphology of the soils and the intermittent trend of the tides caused the accumulation of effluents in the fens. The hydraulic engineer corp had proposed a masonry lock to control the oscillations of the tide. Olmsted instead proposed to tackle the problem of "sanitary improvement of the Back Bay drainage basins" by building sewer infrastructures that divert the flow of wastewater and the Muddy River from the Fens. The move allowed the latter to return its original wet area condition. And yet the system is an eminently artificial one: the connection with the Charles River and the ocean tides is regulated by a weir, which limits the oscillations of the hydraulic level (Krinke 2001). The integration of the "common" landscape into the urban fabric occurs once again through the overlapping of flows: the parkways and promenades that develop along the Emerald Necklace are designed as connecting systems between the two fronts of the linear park. The Necklace is, therefore, at the same time, an ecological corridor and a system of urban crossing and connections. The Fens are structured as a superposition of three layers: an underground skeleton of sewer infrastructures, the modelling of the soil functional to the "natural" wet landscape, the system of urban connections, three layers that make up an urban infrastructure, governed by a lock.

This concept can be paired with the landscape ecological corridor: a linear path connecting large patches of biodiverse landscape, allowing animals to move between patches and therefore increasing the resilience of the system: if something goes wrong animal populations can move to other patches.

2.3 The hybrid urbanisation

The park-infrastrucure, park-system and reclamation strategies point towards a new alliance between urban and natural, that is urgently needed in the context of the rapid rapid growth of the Western city, which came at the risk of completely obliterating vast ecosystems and condemning most of the urban dwellers to a life without nature.

The new hybrid urban-natural highway is the parkway: in Riverside, Illinois, the motorways are remodelled in shape and layout to gently adapt to the landscape, and are accompanied by deep areas reserved to forests: a very early version of ecological corridor, a more pleasant traveling experience, and a system to mitigate noise and pollution effects around the motorways. Landscape architecture, therefore, views the landscape as a perfromative and hybrid element of the human world; a programme and a conceptual model opposed to the neoclassical or baroque garden design, which aimed at the representation of monarchical power or humanistic principles.

The new urban settlement is the suburb, an idea and design typology taken from the English Garden Cities and first experimented in the 1920's Radburn, New Jersey.

Soon after Frank Lloyd Wright will crystallise these ideals in the project of Broad Acre (later Usonia), possibly the most inspired anti-urban or hybrid-urban concept to be ever conceived and the topic of one of the next blog posts.

In conclusion, we have seen three important important concepts emerge from the work of early landscape architects, mostly based in the US.

The first is an open space strategy: a sequence of open (ideally public and green) spaces creates a system that can extend to become a network. The second is the idea of urban regeneration through the coordinated trasnformation of brownfield sites. This processual idea vastly expands the potential for transformation of several territories, while introducing time into the equation of urban transformations: sites are often bought or taken at different moments and will always require different degrees of reclamation or preparation.

The third, only hinted in this post, (I will return to it in more detail) is the idea of stepping stones, where several points form an invisibile continuity just by their proximity.