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Growing Green Cities: Living on the Hedge
Navn
Alex John Buckthal
Uddannelsesgrad
Kandidat
Fagfelt
Arkitektur
Institut
Bygningskunst og Teknologi
Program
Computation in Architecture
År
2023
Fractured urban green spaces have a multiplicative negative impact on biodiversity in cities. This project aims to reconnect urban green spaces into a holistic, green network using living architecture through a multi-scalar design proposition. The project explores how the system could be constructed and its impacts on the local ecology and community.
The project has several goals: to improve local biodiversity, to improve the lives of urban dwellers, but also to work remedially. The era of Haussmannian-style demolition and construction of huge portions of cities into boulevards and networks is at an end. Construction produces 36% of waste in the EU, and demolition projects like Haussmann's reconstruction of Paris often come at the expense of marginalized communities. The project therefore works to also work remedially and avoid any demolition, and to use living architecture to replace wasteful processes in construction.
Hedgerows
Hedgerows criss-cross the landscape of northwestern and northern Europe. The historical legacy of them makes an interesting topic of study, which reveals a huge number of benefits they provide to the agricultural landscape. This project proposes that those benefits can be transferred into an urban environment to take advantage of the huge number of benefits that they provide, including food production, cultural institutions, and most importantly the basis for an improved amount of biodiversity. Hedgerows act as "highways" for animals and plants, allowing disparate populations to interbreed and migrate. Reconnecting cities will mitigate the effect of fractured urban green spaces, which will improve the lives of humans and animals.
Services provided by hedgerows in rural environments
By anticipating the best growing conditions for plants in the city-network, the hedgerow will be less likely to fail. To find the best routes to reconnect green spaces throughout the city, two approaches are considered. The first, called the Geofactor, takes geometric factors into consideration: street orientation, street width, and building height. These 3 things will affect sunlight infiltration and room for tree canopies.
The second method, called the Biofactor, looks at satellite imagery that can reveal areas of more and less healthy plant growth, called the Normalized Difference Vegetation Index (NDVI). By rating intersections by their relative NDVI score, we can finding the highest scoring streets that are either ideal for plant growth, or have existing plant growth that the hedgerow network can tie into.
To explore possibilities within living architecture, the project needed to have a better understanding of how trees grow and the range of their forms. I chose ac common tree species to investigate, the European Hornbeam, and scanned several species in Copenhagen.
I analyzed the scans through a voxelization method that can turn the tree into a topological skeleton model, and used data from that result to inform an L-System simulation, which is used to simulate plant growth. The goal was to create an idealized set of rules to simulate the European Hornbeam, but the simulation was never as flexible or diverse as the observed species.
My research showed me that the form of a tree is hugely dependent on its growth and care. Trees can be pruned or damaged and have branches removed, they can be formed into shape as the grow to create new, specific, bespoke forms, or can undergo an additive process called inosculation, where two trees grow together so closely that they merge into one organism. The form of a tree is therefore quite flexible and can be used to create either a free, sculptural form or a regular, rational architectural form.
3D scans of several hedgerows, compared.
The services that hedgerows provide are based largely on the form of the hedgerow, in addition to biological function. To better understand the form, I took several 3D scans of hedgerows around Roskilde, Denmark. The forms were related to programs and functions, and I propose that these programs can be translated and utilized in an urban environment.
Potential biodiversity increase, and resident organisms.
The project aims to increase local biodiversity by addressing the material requirements for expansion of the local ecosystem into the new hedgerows. Ecologists will select species to design re-greening efforts around, and this project will use the concept of an Umbrella Species, that is, one who's environment will encompass many other species that also can thrive in that environment as a subset. The project selects the red squirrel, a native species of Denmark that lives in hedgerows. The project analyzes organisms that interact with the red squirrel from data retrieved from the Global Biotic Interactions database and the Global Biodiversity Information Facility, and uses studies of plant succession on walls to anticipate how to create an ecosystem that encompasses the plants that our umbrella species interacts with.
Pattern of ecological succession on walls.
The project proposes the form of the hedgerow to be made of a series of trees planted along the facades of Copenhagen. The flexibility of tree forming is a tool that the local residents of the building can use to create a desirable function, whether it be circulation, a park, a playground, etc, through community driven design. The system grows over time to be a richer, fuller hedgerow and programmatic experience.
Community driven design allows for a huge amount of flexibility in what the hedgerow system gives back to local residents. Here, the residents have created a playground. During the day, the residents use it for recreation, but the system works as a proper hedgerow, giving animals a way to migrate through the city.
View from an apartment at Valkyriegade after the hedgerow infrastructure is added.
The experience of living in an apartment in the hedgerow system is a positive one. Here, circulation outside your window and balcony develops a sense of local community, and improves the view from the window from a street devoid of plants to a rich garden of local plants.
To accelerate ecological succesion, the project proposes wall-mounted "autoecological accelerators" to be included. The pieces function as spaces for plants to grow and colonize over time, as well as giving back function to animals and humans alike.
Det Kongelige Akademi understøtter FN’s verdensmål
Siden 2017 har Det Kongelige Akademi arbejdet med FN’s verdensmål. Det afspejler sig i forskning, undervisning og afgangsprojekter. Dette projekt har forholdt sig til følgende FN-mål
