Jean-François Gauthier_Trees First

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The Public Spaces of the Forest-City

Trees First



Tomorrow, we will plant forests in our cities rather than trees. Let’s focus on trees in the city and their needs as a starting point for a better design of public space. Let’s look at the city as a potential forest territory. Let’s establish new public space typologies around tree communities. Forest succession will bring a new temporality and healthy urban living in our densely populated cities.

The Public Spaces of the Forest-City

Trees First


Trees First The Public Spaces of the Forest-City Master of Landscape Architecture Academy of Architecture Author Jean-Franรงois Gauthier Committee Members Jana Crepon (Mentor) Mirjam Koevoet Wiebke Klemm Amsterdam, August, 2019


Index

What is a Forest?

Brussels as a Forest

Where Extremes Meet

14 A Territory

40 Brussels Under Heat Waves

70 The canyon Forest | | BVD Anspach

24 A Community

42 Geographical conditions

88 The Hill forest | Square Anneessens

32 A Time Landscape

44 The Initial Forest

98 The Wetland Forest | Fontainas Park

34 3 Guidelines for the Forest-City

46 The Modern City

118 The Mountain Forest | Brouckere Towers

50 Toward a Forest-City

127 A Matrix for the Forest-City

55 A Hidden Water Structure 58 An Artificial Topography 60 A Pedestrian City Centre 62 A Mosaic of Habitats

A Territory

Wetland Mountain

Experience A Time Landscape

A Community

Canyon Hill


Preface

Trees First My interest in Landscape Architecture started with a fascination for drawings and for the painters from “Barbizon” school, which were the first artists painting “on-site”, in the XIXth century. What strikes me the most is the fact that their only topic was the forest, as if the richness of this environment could never be caught completely and as if the forest was the essence of Art. While doing experimentation myself in the same condition, I realised how difficult it was to draw a tree and how easy it was to paint it. Drawing a tree out of its living context didn’t seem to work while painting it as part of its immediate surrounding seemed right. The painting medium taught me that trees are always connected to their environment and cannot be extracted from it. In landscape architecture; materials, textures and vegetal elements are the basics of our profession. However, the bigger scale brings new layers to deal with. Let’s think of program, car traffic, underground layers, and other pragmatic questions. As a consequence, nature becomes a secondary choice in landscape design. I want to ask myself if a landscape design could be different. Can nature and trees play a leading role in every step of the design process?

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On-site sketching: first step in my understanding of forest

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Increase the Tree Cover

A new goal on the urban agenda Increasingly, adding trees to the city is a new goal on the urban agenda in order to fight climate change. Scientific studies explain that trees are our allies to reach sustainable goals such as: - The heat mitigation and the cool island effect thanks to the evapotranspiration phenomena. - The improvement of the air quality thanks to the photosynthesis phenomena and the Co2 absorption. - The resilience of the city thanks to wind, noise protection and the buffering of rain-water. - The increasing of the quality of life and citizen health thanks to the development of nature and biodiversity within the city.

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News article selection showing the importance of trees in world megalopolis

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A Change of Attitude

The Concrete-City of Today In European cities, trees are still seen through a utilitarian perspective and as urban furniture. As a consequence, the average life span of a tree in urban conditions is only 30 years. As 75 per cent of the population is expected to live in an urban setting by 2050, a radical approach towards urban nature is needed. Planting trees is not enough; planting forest should become a precondition for a healthy living and urban development.

The Forest-City of Tomorrow Tomorrow, we will plant forests in our cities rather than trees. Cities will adapt to forest plant communities needs. Space will be made for forest succession and spontaneous growth to proceed. Cities will receive great benefits in return in terms of ecosystem services, and urban forests will contribute to public health. In this project, we will focus on trees in the city and their needs as a starting point for a better design of public space.

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Urban Heat Islands

Pollution Concrete city

Accidental Nature

Controlled Nature Climate Change

Trees as urban furniture

Nature thought ahead

Forest rather than trees

Sustainability Ecology

Purification Physical Experience

Permeable city

Urban Development

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What is a Forest?



What is a Forest?

An Ecological Definition Looking for a forest definition, one would find hundred of variation, coming from different fields of study such as forestry, literature, landscape architecture or land management. In this project, trees and their ecological needs will be our starting point. To do so, three main themes will help us to give a forest definition. A Territory Environmental conditions define key forest habitats. Trees are adapting specifically to different factors such as the topography, the light, the heat, the hydrology, the soil and the nutrient cycles. A Community A forest is more than a collection of trees competing with each other for light. It is a living organization where trees exchange resources with each other and with animals. Recent book such as The Hidden Life of Trees, explain this new ecological knowledge on forests and their underground social network. A Time Landscape From pioneer stage to climax stage, forests are ever-changing. Ecological succession brings dynamic changes and constant evolution of the plant-community. Walking in the forest, our experience will vary greatly depending on these three themes. In this chapter, we will go through these three themes, and compare forest growth in natural conditions and in urban conditions. In a second time, we will give a definition of the Forest-City, its challenges and its opportunities. Finally, we will define guidelines to build the Forest-City.

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A Territory Habitats

A Community A Forest

Underground Network

A Time Landscape Ecological Succession

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A Territory

Natural Conditions “Almost no habitat on Earth offers ideal living conditions [---]. There are many number of difficult sites, and a tree that can get along in such places can conquer an enormous geographic range. Ideal conditions are nowhere to be found and that is a good thing for diversity.” (The Hidden Life of Trees, 2016, p.75).

Urban Conditions “We have to face the fact that many of the species that have been evolving and adapting to the urban environment most successfully are non-native” (Darwin comes to town, 2018, p.179 ).

What is a Forest?

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Mountain

Plateau

Steep Slope Hill

Canyon

Wetland River

Mountain Plateau Steep Slope Canyon Hill Hill River

Wetland

17


A Territory Environmental Factors

Natural Conditions The adaptation of trees towards very specific conditions result in the formation of forest communities. In every habitat, the light, the heat, the water, the soil and nutrient cycle are key factors for trees development.

Urban Conditions Looking at city habitats, soil is often very compact and the space for roots development is limited. Heat island effect, droughts and floods create extreme urban conditions. Native species are struggling to survive in this harsh environment. Urban habitats studies will allow us to select suitable trees for our city forests. Radical city transformations are required to allow new nature to settle.

What is a Forest?

18


Light and Heat heliophytes

mi-shadow

sciophytes

Water

hygrophytes

mesoxerophytes

mesophytes

Soil and Nutrient

Light and Heat

urban heat island

limited sun

Water

flood and pollution

drought

Soil and Nutrient

impermeability and lack of nutrients compact and covered clay

sandy soil and fast water runoff

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A Territory Habitat Mosaic

Natural Conditions Challenges coming from the environmental condition define contrasted key forest habitats. Depending on these habitats, forest spatial organisation can varies greatly.

Urban Conditions Human activities have deeply transformed landscapes to create modern cities. Artificial conditions in the city are closer to extreme habitats in natural landscape than to the initial landscape where cities were built. In the new urban conditions extreme habitats can be find next to each other on a small scale. It is an opportunity for a new type of nature to settle in the city.

What is a Forest?

20


Mountain

Plateau

Canyon

Steep Slope

Hill

Wetland

Mountain

Plateau

Canyon

Steep Slope

Hill

Wetland

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A Territory Ecological Network

Natural Conditions On a broader scale, forest habitats are organised through sources, corridors and stepping stones. Together, these populations form an ecological network and meta-populations as described in the book Landscape ecology principles in landscape architecture. The forest territory is not a uniform landscape but rather a mosaic of habitats. Gradient from open grassland to woodland create dynamics from open to closed space. Edges between habitats are as important as the habitats itself.

Urban Conditions In urban conditions nature is fragmented and highly disturbed by human activities. However, looking at the city as a potential territory, parks could be seen as forest sources; streets could be seen as corridors and squares could be seen as stepping stones. To protect this urban ecological network, the interface between forest communities and public space becomes key and requires design attention.

What is a Forest?

22


Source Stepping stone Corridor

Source

source Park

Corridor Streets

Stepping stone Squares

Source

Forest remains

23


A Community

Natural Conditions As discovered by Suzann Simard in the Architecture of the Wood Wide Web, a forest is an interwoven system rather than a collection of trees. Older trees are connected with each other thanks to underground mycorrhizal networks and share resources and informations.

Urban Conditions “Whereas forests cool themselves on hot summer nights, streets and buildings radiate the heat they soaked up during the day, keeping temperatures elevated [---] Many of the companions that look after trees’ well being in the forest (such as micro-organisms that make humus) are missing. Mychorrhizal fungi that help collect water and food are present only in low numbers. Urban trees, therefore, have to go it alone under the harshest conditions” (The Hidden Life of Trees, 2016, p.175).

What is a Forest?

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stability: trees supporting each other wind is stopped at the edge

sunlight is not reaching the ground

micro-climate: soil generating humidity in trees shade 50.00m

water absorption is progressive

high and fast transpiration

artificial light

heat reflection

building shadows (reduced photosynthesis) hydrocarbons

limited space for the root system and dry soil

Diagram adapted from the Architecture of the wood-wide web, Kevin J. Beiler, Suzanne Simard

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A Community Mother Trees

Natural Conditions Mother trees help younger trees from their own species by giving them nutrients through funghi exchange. They bring shade for the seedlings to grow slowly and steadily.

Urban Conditions Urban trees from nurseries are growing solitary, receiving intensive care in their younger years. The contrast with the urban conditions is extremely high in terms of soil quality, access to water and heat. As a consequence, trees from nurseries are not adaptive to the harsh urban conditions they will met when moved to the city.

What is a Forest?

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genetic diversity

mother tree great photosynthesis

young tree being nursed in the shade

water and sugar exchanges

NURSERY

CITY full sun

Spoiled tree facing harsh city conditions fast growth abundant water

monoculture container

instability and horizontal growth

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A Community Veteran Trees

Natural Conditions The older a tree gets, the more important it becomes for biodiversity and for the plant-community living around.

Urban Conditions Veteran trees are ideal shelter for the biodiversity we need in our cities (mushrooms, symbiotic bacteria, plants growing on the tree, lichen, moss and animals living around). However, the average life span of a tree in urban conditions is 30 years. It is a design challenge to create better conditions in cities for trees to grow older.

What is a Forest?

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0

200 - 1600 years

Biodiversity

high potential for urban benefits

average life span of a tree in urban conditions

acceptance 0

27 years

200 - 1600 years

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A Community The Forest floor - Plant community

Natural Conditions Looking closer to the forest floor, the first 30 cm below ground are the richest thanks to organic material and loose soil. It is also the place for mychorrhization to happen, funghi reach water sources and share it with trees; in exchange trees share produced sugar from photosynthesis. Roots diameters can be 2 to 3 times wider than the tree crown.

Urban Conditions “When trees are planted in these restricted spaces, conflicts are inevitable. [...} When trees in urban areas run up against ground as hard as concrete wherever they turn, they get desperate, and it is only as an absolutely last resort that they finally find a way out into sloppily backfilled trenches.� (The Hidden Life of Trees, 2016, p.175).

What is a Forest?

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photosynthesis O2

Richer soil in the first 30cm

H2O evapotranspiration

CO2

organic material

water run-off

tree litter mycorrhization infiltration

minerals and water absorption

bedrock

First 30cm covered

unspoiled bedrock

paving on top of the richer soil compact soil

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A Community Forest Edge

Natural Conditions “At the edge of the forest, the rules for straight trunk growth are not quite strict. Here, light comes in from the side, from a meadow or a lake - places where trees just don’t grow. Smaller trees can get out from under larger ones by growing in the direction of the open area. Deciduous trees, in particular, take advantage of this.” (The Hidden Life of Trees, 2016, p.41).

Urban Conditions At the edge between open and closed habitats, the highest biodiversity can be found. However forest edges are absent in the urban paved areas. As a consequence fauna is limited. Understory is also absent in public spaces. The cool-island effect around trees is therefore less intense.

What is a Forest?

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30m

50m

30m

Forest Edge

Forest Community

Forest Edge

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A Time Landscape

Natural Conditions Before reaching a stable social structure, trees are colonizing new areas. In this pioneer stage, Populus, Betula and Salix will grow fast and regenerate the soil. Acer, Fagus, Carpinus, will grow slowly in the shade of the pioneer trees and later replace them. In a climax forest, different succession can be seen next to each other and form a mosaic of stages.

Urban Conditions Dense urban area create fragmentation within woodlands. Pioneer trees are often visible in left-over spaces. Older trees in european capitals can often be seen in private areas such as gardens or cemeteries. If we want to bring back old trees in public spaces, it is important to define clear spaces and borders for trees to grow old. Different urban typologies require different strategies for succession to happen. Depending on the constraints, the maintenance will be higher or lower.

What is a Forest?

34


1 Year: from Annual to Perennial Grasses

10 Years: Pioneer Forest

30 Years: Pioneer Replacement

40 Years: Replacing Forest

90 Years: the First Natural Generation Dies

100 to 200 years: Climax Forest

1 Year: Tree Nurseries

10 Years: City Leftovers

30 years: Street and Square

40 years: Parks

90 years: Courtyard and Garden

Stages Fragmentation

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3 Guidelines for the Forest-City

Trees First A Territory Urban habitats studies will allow us to select suitable trees for our city forests where extreme habitats can be find next to each other on a small perimeter. It is an opportunity for a new type of nature to settle in the city. A Community The interface and edges between natural areas and public areas is key to protect forest communities from urban disturbance. By creating clear edges, nature is given a holy character. These woodland edges will vary greatly depending on the forest and the urban typologies. A Time Landscape Different urban typologies require different strategies for succession to happen. Depending on urban constraints, the maintenance will be higher or lower. Natural process in public space brings a new temporality and social inclusiveness around urban forest.


A Territory Urban Habitats Mountain Plateau Steep Slope Canyon Hill Hill

River

Wetland

A Community A Forest-City

A Time Landscape Succession Strategies

Dissemination Strategy

Diversification Strategy

Composition Strategy

Vertical Growth Strategy

Minimum Forest


Brussels as a Forest



Brussels as a Forest


The forest-city as dreamt by Brussels inhabitants Rue du Grand-Serment, mural by Brecht Evens


Cities Under Heat Waves What can we do?

In this project, we will take the very centre of Brussels as a case study for an urban forest to settle. As shown in this extract taken from the VRT news, it is urgent to bring nature back in our city-centre:

“Temperatures are rising, especially in the city. Also in Brussels, where parts of the city turn into urban heat islands. Marie-Leen Verdonck is expert in city climate and has studied this theme for years. Marie-Leen Verdonck: Everywhere around us there are buildings and paving, and all this stone absorbs heat. Next to this, there is almost no vegetation, no trees, no grasses. This absence of green makes sure that the city absorbs heat the whole day and in the evening the city becomes a source of heat. All the rough materials are excessing heat during the evening, which ends up in the city cooling down really slowly during the night. Even during late hours at night, the city stays warm and can hardly lose its own heat. When your body is constantly exposed to high temperatures, you will experience a constant feeling of stress, you can hardly concentrate and become easily grumpy. We should really think about how to let green be a bigger part of our cities, creating a more healthy living environment.� Translated from Dutch | VRT news, July 25th, 2019

What is a Forest?

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Screenshot taken from VRT news, July 25th, 2019

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Geograhical Condition

The Broad-Leaved Forest Brussels is located between the Northern edge of the Ardennes and the coastal plains of Antwerp. In this area, many small rivers shape a gentle topography before flowing in the Senne which is one of L’Escaut river‘s watershed. These geographical conditions are typical of Western european broad-leaved forests growing in submontane areas, valleys and lowlands.

Brussels as a Forest

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The Coastal Plain Sea and Scheldt influence in Antwerp

The Central Plateau The Broad leaved Forest: • Gentle topography and side valleys shaping Brussels • River Senne part of the river Escaut watershed

The Northern Edge of the Ardennes Charleroi highlands and Hilly landscape

N

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The Initial Forest

Natural Conditions Looking closer at Brussels geology, a clear contrast can be noticed between the West and the East part of the Senne River. In the Eastern lowlands, tributaries and sandy-clay soils create conditions for wetland forest to grow. On the West side, the topography is more striking. Limestone hills and plateau define a landscape more suitable for mixed Beech forest. In roman time, the city has been built at the edge between the valley and the higher lands of Brussels West. As a consequence, most of the wetland forests have been cut during the creation of the city.

140 m 60 - 80 m

0 - 20 m

West Wetlands (sand and clay)

Brussels as a Forest

East Hills and Plateau (sand and limestone)

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N

47


The Modern City

Grey versus Green city Walking in the modern City, is it still possible to experience the initial Brussels forest? Natural remains can still be found in parks located in the tributaries valleys and in forest left-overs in the outskirts of the city (for example the Sonian forest). However, city development has transformed the initial landscape dramatically. The Senne Valley has been completely industrialised. In the city centre, the water system is artificial and the environment is mineral. As a consequence, trees are nowhere to be found in the heart of the city.

Initial Forest Remains

Artificial water cycle

Brussels as a Forest

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N

49


Opportunity

Heat Island and Impermeability City transformations has led to a dramatic decrease of nature, especially in Brussels city-centre. It is a paradoxical situation, where the initial lifeline of Brussels, the Senne Valley, has become the harshest and driest environment of the city. This is an opportunity as well as a challenge to bring back nature here and to invent new forest typologies serving the resilient city.

Brussels as a Forest

50


N

51


Towards a Forest-City

Where extremes meets In this project area we will focus on the challenging Brussels city-centre and especially on the surrounding of the former Senne river valley. Here, urban transformation has been so radical that extreme potential forest habitats can be found within a very small perimeter. A hidden water system, artificial topography and remains of the initial Brussels valley define a potential forest territory. Different urban situations and very contrasted forest habitats can be found within the perimeter of the Boulevard Anspach and its surroundings. It is an opportunity for a new experience of nature in the most dense part of the city. On a broader scale, it is a chance to study exemplary conditions for Brussels development.

Brussels as a Forest

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N

53


Project Area

Former Industry | River Senne

Fontainas Park

Brouckère Towers

Annessens Square

Anspach Boulevard

Former Industry | River Senne

Brussels as a Forest

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Former Industry | River Senne

Brouckère Towers

Anspach Boulevard

Fontainas Park

Annessens Square

Former Industry | River Senne

N

55


A Hidden Water Structure

The Life-line of the City Center? As in many european cities, Brussels Senne river has been covered in the 19th century. Streets in the lowest part of the city follow the river Senne initial water course. In the Boulevard Anspach and Maurice Lemmonier, the river Senne is canalised 1 meter below ground. Its is a combined system mixing rainwater and sewage. By separating rain water and sewage water, there is an opportunity to create a water reservoir for the newly planted forest. At the same time, it will act as a water buffer zone for the city-centre.

River Senne initial water course Canalised River Senne Open-air River Senne

Where Extremes Meet

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SECTION LINE

N

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A Water Reservoir for the Forest-City

Proposal Existing situation • A Combined rainwater and sewage system in the lowest part of Brussels Proposal • To separate rain water and sewage water Rain Water Buffer in Winter • A water reservoir for the new forest • A water buffer zone in the lowest part of the city collecting and retaining water from roofs and public spaces • To clean the collected rain water before letting it flow back into the river Senne Cool Island Effect in Summer • Healthy forest and evapotranspiration • A water storage for drought emergency

Where Extremes Meet

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Existing Situation

Proposal

Rain Water Buffer in Winter

Cool island in Summer

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An Artificial Topography

Opportunity for New Nature In Brussels, modernist towers were built right next to historical buildings. At the same time, metro lines were constructed and are running right under the city-centre. These urban layers bring a new topography and verticality in the former Senne valley. It creates a “canyon effect� in the centre boulevards and opportunities for new mountain forest habitats to settle.

Modernist Towers M

Metro Station Metro Lines

Where Extremes Meet

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N

61


A Pedestrian City-Center

Experiment the New Nature Brussels municipality is developing projects to give more space to pedestrian in the city-centre. A plan is being realised to turn Boulevard Anspach into a pedestrian shopping Boulevard. We propose to extend the pedestrian area untill the Boulevard Maurice Lemmonier. The traffic could be reorganised thanks to a loop system. Minimum amount of crossings could be carefully chosen within the future forest area. A peaceful area will allow pedestrian to discover the new nature.

Where Extremes Meet

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N

63


A Mosaic of Habitats

River Forest

Wetland Forest

Mountain Forest

Hill Forest

Canyon Forest

River Forest

Brussels as a Forest

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River Forest Former industry

Mountain Forest Brouckère Towers

Canyon Forest Anspach Boulevard Wetland Forest Fontainas Park

Hill Forest Annessens Square

River Forest Former industry

N

65


Where Extremes Meet Boulevard Maurice Lemonnier | Boulevard Anspach

Wetland Forest Mountain Forest Canyon Forest Hill Forest



Where Extremes Meet

A hidden water system, artificial topography and remains of the initial Brussels valley define a potential forest territory. Different urban situations and very contrasted forest habitats can be found within the perimeter of the Boulevard Anspach and its surroundings. Four main forest typologies are defined: the Canyon Forest Boulevard, the Hill Forest Square, the Wetland Forest Park and the Mountain Forest Towers. A green network will be built around these four forest typologies. New urban programmes can be developed around them. Soil continuity and permeability are the precondition for the new forest to settle as well as for the city to become resilient.

Elementary school

The Wetland Forest

Pre-School

The Hill Forest Institut Cooremans Institut Anneessens-Funck

Boulevard Maurice Lemonnier

Boulevard Anspach

Place Fontainas

Palais du Midi

Where Extremes Meet

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Béguinage

Sainte Catherine

Halles de Saint-Géry

The Mountain Forest

Notre-Dame aux Riches Claires

The Canyon Forest

Place de la Bourse

Place de Brouckère

Boulevard Anspach

Centre Monnaie

Saint Nicolas underground river Senne La Monnaie


The City-Forest

Just like in a forest “meta-population”, the Canyon-Boulevard serves as a “corridor” for fauna and flora, as well as a water reservoir. Thanks to theirs important size, the Mountain-Towers and the Wetland-Park are important “forest sources”. The HillSquare is a “stepping sone” in this networks. Roof-top and green facades can be seen as “forest edges”. Clear edges are defined to protect forest-communities. Soft or hard boundaries around natural areas are created according to the urban pressure. These plant-communities are reacting to the scale of the spaces they settle in. For each habitats, a successions strategy is defined.

Elementary school

The Wetland Forest

Pre-School

The Hill Forest Institut Cooremans Institut Anneessens-Funck

Boulevard Maurice Lemonnier

Boulevard Anspach

Place Fontainas

Palais du Midi

Where Extremes Meet

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Béguinage

Sainte Catherine

Halles de Saint-Géry

The Mountain Forest

Notre-Dame aux Riches Claires

The Canyon Forest

Place de la Bourse

Place de Brouckère

Boulevard Anspach

Centre Monnaie

Saint Nicolas La Monnaie


The Canyon Forest

A Territory

A Community

• Contrasted seasonal changes from flood to extreme drought

• Linearity and pioneer clumps • Open under-story

• Sandy soil, maximum drainage • Tree roots tolerant to water-logging • Minimum root space • Green Walls • Moisture gradient

Where Extremes Meet

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A Time-Landscape

Program and Urban Benefits

• Composition Strategy

• Pleasant pedestrian boulevard

• Combining pioneer trees and target species

• Living and shopping area • Water buffer for the city centre • Water squares • Cool island effect from green walls • Ecological corridor

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The Canyon Forest Boulevard Maurice Lemonnier Sequence 1

Contrasted seasonal changes from flood to extreme drought, green walls, open perspective, sunken forest, clumps and open under-story define the Canyon Forest Boulevard.

underground river Senne

trees in planters boulevard Maurice Lemonnier

metro access car traffic

cafĂŠ

Where Extremes Meet

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Prunus

A

Aln

Forest Fringe

ndula

Salix alba

The Canyon Forest Boulevard Maurice Lemonnier

M

Alnus glutinosa

Plan Existing - Plan Project

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The Canyon Forest Boulevard Maurice Lemonnier Sequence 1

The Canyon Forest typology preserves the monumental aspect of the boulevard as the central perspective remains open. Bridges crossing the sunken areas allow people to meet in the centre of the Boulevard where views are kept open. Canyon green walls enhance the historical façades. Pleasant edges and steps between the terraces and the forest clumps allow people to experience the water buffered in the heart of the Boulevard.

boulevard Maurice Lemonnier

monumental perspective

trees in planters

sewage

trees in planters

River Senne collector

cafĂŠs

sewage

Sidewalk

Car Traffic

Sidewalk

5.90

16.70

5.90

Where Extremes Meet

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green faรงade

retained monumental perspective

Betula pendula Salix aurita

bridge

overflow

2% >

< 2%

gully

Canyon Facade

Pedestrian

Canyon

Pedestrian

1.50

4.50

16.40

6.00

Section Existing - Section Project

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The Canyon Forest Boulevard Maurice Lemonnier Sequence 2

In this sequence, the Canyon Forest becomes minimum since the metro station is located 1 meter below ground. Swales are created on top of the canalised river Senne which flows along the facades, on both sides of the street.

underground river Senne

cafĂŠ

car traffic

boulevard Maurice Lemonnier

trees in planters cafĂŠ

Where Extremes Meet

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forest playgrounds Sorbus a

Pre-School

Acer pseudoplat

t Cooremans

Quercus b

Hill Forest e Anneessens

Dryland Vaccinium myrtillus

platanus

Forest Fringe

Tilia cordata

etulus

a

Hotel Barry Café Swales

alba

Betula pendula

Space for Events

Green Façade

Plan Existing - Plan Project

Café

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The Canyon Forest Boulevard Maurice Lemonnier Sequence 2

In the center of the Boulevard, space for events such as local market is kept. Soil continuity comes from a linear dry prairie meadow. Little by little wild flowers and shrubs will grow and form an early forest succesion in the canyon area.

BVD Maurice Lemonnier

metro access

river Senne collector

metro

sewage

river Senne collector sewage

Sidewalk

Car Traffic

Sidewalk

5.60

16.70

5.60

Where Extremes Meet

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green faรงade open space for event

swale

Pedestrian

Swale

Dry Meadow

Swale

Pedestrian

4.00

1.60

13.60

1.60

4.00

Section Existing - Section Project

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The Canyon Forest Place de la Bourse Sequence 3

“Place de la Bourse” is a meeting point for people coming from higher city district and going down to the city-center. It’s also a big metro station and an important space for events and demonstration. Here the canyon effect will be even stronger than in the rest of the Boulevard as the Forest will sunken untill the metro station leel.

M

M

Place de la Bourse

Bourse de Bruxelles

underground river Senne

Where Extremes Meet

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Sunken Forest

M

Forest Fringe

M Salix aurita

Salix alba Boulevard Anspach

The Canyon Forest Place de la Bourse Large Open Space for Events

Bourse de Bruxelles

Église Saint Nicolas

Plan Existing - Plan Project

83


Where Extremes Meet

84


The Canyon Forest Place de la Bourse Sequence 3

Walking out from the metro, people will already experience the verticality and green walls of the Canton Forest. On the square, nature is well protected thanks to the spatial configuration. Maximum space is kepts for big events on ground floor. The forest canopy becomes an attraction and a landmark.

Place de la Bourse

Metro Access

River Senne collector

sewage

Section Existing

River Senne collector

sewage

85


Platanus orientalis Salix aurita

Metro Access

River Senne collector sewage

Sunken Forest 13.50

Where Extremes Section Meet Existing Boulevard - Section Anspach Project - Place de la Bourse | 1-200e

86


Place de la Bourse Bourse de Bruxelles

Wide Open Space for Events

River Senne collector sewage

Urban Square 48.00

Section Project

87


The Canyon Forest Plant Community

Stones giving stability to trees

Platanus orientalis

Alnus glutinosa

Populus nigra

Canyon Green Wall

Salix aurita

Melissa officinalis

Parietaria erecta

Salix Alba

Urtica dioica

Gradient from dry to wet meadows

Pioneer roots network growing horizontally

Pioneer ability to grow on steep surface

Alnus cordata regenerating soil fertility through symbiotic nitrogen fixation

Where Extremes Meet

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89


The Canyon Forest Time Landscape

Today: Boulevard Maurice Lemonnier

Pioneer Settlement

Rain Water Buffer in Winter

Cool island in Summer

Where Extremes Meet

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The Canyon Forest | Development in Time

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The Hill Forest

A Territory

A Community

• Lowlands and lower slopes of hills

• Tree community at the edge between low and high land

• Space for roots development • Gradient of conditions, from wet to dry

Where Extremes Meet

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A Time-Landscape

Program and Urban Benefits

• Renewal strategy

• Reinforce urban life (existing cafés, hotel)

• Diversification around Mother Trees

• Cool island in the heart of the city

• Under-story development

• Stepping stone for urban fauna

• Careful tree selection in the secondary succession

• Enhance historical buildings • Move existing market to the Boulevard

• Maintenance close to natural processes

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The Hill Forest

The Hill Forest square can be found at the edge between the valley and higher land; a gradient of moisture defines a specific habitat where Tilia cordata is the key community species.

Tilia roots searching for lose soil in existing situation

underground river Senne

Haute ĂŠcole Francisco Ferrer

Prunus avium

Tilia cordata

hotel Barry metro access boulevard Maurice Lemonnier trees in planters cafĂŠ

Where Extremes Meet

94


Institut Cooremans

The Hill Forest Square Anneessens

Vaccinium myrtillus Prunus avium

Acer pseudoplatanus

Forest Fringe

Tilia cordata

Carpinus betulus Alnus glutinosa

M

Swales

Salix alba

CafĂŠ

Plan Existing - Plan Project

Hotel Barry

Space for Events

Green Façade

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Where Extremes Meet

96


The Hill Forest

Three steps going down towards the former valley define the hill forest edges, creating a gradient from wet to dry conditions. Three crossing are designed to allow pedestrian to experiment these natural gradients and forest conditions.

boulevard Maurice Lemonnier Haute ĂŠcole Francisco Ferrer

2% >

Section Existing

hotel Barry

car traffic

Sidewalk cafĂŠ


Tilia cordata

Quercus borealis

Haute ĂŠcole Francisco Ferrer

Tilia

Prunus avium Acer pseudoplatanus

Vaccinium myrtillus Crossing and Seating Edge

Pedestrian 12.40

Where Extremes Meet

Dry edge

The Hill Forest

17.50

98


Tilia cordata

a cordata

Carpinus betulus Alnus glutinosa Crossing and Seating Edge

hotel Barry Bridge

Seating Edge

River Senne collector

River Senne collector sewage

Section Project

sewage

Wet edge

Pedestrian

37.00

6.00

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The Hill Forest Plant Community

Allium ursinum

Narcissus pseudonarcissus

Tilia cordata

Melampyrum pratense

Prunus avium

Vaccinium corymbosum

Anemone nemorosa

Acer pseudoplatanus

Tilia as mother trees giving nutrients to siblings thanks to mycorrhizal exchange

Dry edge crossing

Bridge

Wet edge crossing

Where Extremes Meet

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101


The Hill Forest Time Landscape

Today: Tilia cordata as Mother Trees

Enhancing the Hill Forest Habitat

Dry and Wet Edges development

Secondary succession

Where Extremes Meet

102


The Hill Forest | Development in Time

103


The Wetland Forest

A Territory

A Community

• Lowest part of the city landscape

• Constant moisture

• Island and wetland territory

• Habitat mosaic: valley, wet fringe, plain

• Brussels initial Forest

Where Extremes Meet

104


A Time-Landscape

Program and Urban Benefits

• Spreading strategy

• Social Forest (involving schools and inhabitants)

• Natural regeneration Protected and holly islands

• Forest edges cultivated by the inhabitants • New types of sports at the edge of the Forest

• Protecting nature and slowly moving edges • Water sponge for the city • Maximum biodiversity

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The Wetland Forest

The Wetland Forest Park lies in the lowest part of Brussels; it is a mosaic of wet habitat to be found in the plain, the valley and the wet fringes. The main re-creative path cross these different habitats. Parking at the edge of the park are reclaimed and turned into a continuous swale collecting water from the neighbourhoods. A pedestrian loop explores the different forest edges: wetland, playgrounds and food-forest create social interaction between the city and the Forest.

underground river Senne

rue Van Artevelde

buildings recently removed private garden

football

ping-pong tables pre-school basketball

playground

playground institut AnneessensFunck

trade union building playground

place Fontainas

Where Extremes Meet

rue de la Grande Ile

boulevard Anspach

106


forest gardens

Alnus glutinosa

forest playgrounds Sorbus aucuparia

Salix alba Salix pentandra

Pre-School

Wetland Acer pseudoplatanus

Quercus borealis

Tilia cordata The Wetland Forest Fontainas Park

Dryland

Institut Annees

Place Fontainas

CafĂŠ

Salix alba Populus nigra

Betula pendula

The C Boule CafĂŠ

Plan Existing - Plan Project

107


The Wetland Forest

Thanks to its generous size, the wetland forest is an important forest source in the project area. The park becomes a social forest where time and space is given to inhabitants to experiment natural regenaration and forest dynamics.

Acer pseudoplatanus Sorbus aucuparia

Salix alba

Alnus glutinosa Salix pentandra

Forest Fringe Recreative Path

Pedestrian

Wetland

10.00

74.00

Where Extremes Meet

108


Tilia cordata

Quercus borealis

Populus nigra

Entrance

Seating Edge

Dryland

Wetland

Pedestrian

91.00

52.00

12.90

Section Existing - Section Project

109


The Wetland Forest Plant Community

Alnus glutinosa

Veteran Trees are ideal shelters for symbiotic bacteria

Lysimachia vulgaris

Mentha aquatica

Iris pseudacorus

Caltha palustris

Equisetum telmateia

Salix Alba

Central path crossing habitats

Later succession occurs in dryer ground

Populus as landmark for the Bouevard

“Ahah� principle as soft border for the park

Where Extremes Meet

110


111


The Wetland Forest Time Landscape

Today: Scattered sports and playgrounds

Celebrating Trees

Pioneer Development

Secondary Succession

Where Extremes Meet

112


The Wetland Forest | Development in Time

113


The Mountain Forest

A Territory

A Community

• Contrasted and extreme conditions

• Communities of specialists

• Steep slope and vertical territory • Limited soil

Where Extremes Meet

114


A Time-Landscape

Program and Urban Benefits

• Vertical growth strategy

• Modernist building to transform (architectural typology with loading capacity) • Governmental offices and shopping centre to reinvent • New public space in the dense city • Collecting rain water and cool island from roof landscape •Fauna development

115


The Mountain Forest

The Mountain Forest Towers is a vertical and contrasted territory where very specific tree communities can survive. Modernist towers are ideal structure to be transformed into steep forest territory. Space is reclaimed in the tower. The strict structure of poles and beams is used to create forest space from the ground towards the top of the mountain tower.

Brouckère Tower

Boulevard Anspach

Brouckère Tower

Place de la Monnaie

La Monnaie

Where Extremes Meet

underground river Senne

116


M

Alnus glutinosa

Vertical Forest

The Ca Place d

The Mountain Forest

alba Quercus petraea Pinus nigra

Prunus mahaleb

M

Centre Monnaie

Horizontal forest

Betula pendula

Plan Existing - Plan Project

La Monnaie

117


Where Extremes Meet

118


The Mountain Forest

Thanks to their size, spatial configuration and sun orientation, the towers gives opportunities for very specific mountain forest habitats to settle.. From the canyon level to higher elevations, the forest flows into the building horizontally and vertically. New working environment is designed around canyon, caves or grasslands. It is new type of public space, a scale-down landscape system to experience which offers new views on the city-scape.

Section Existing

119


Pinus nigra

Betula pendula

The Vertical Forest

sewage

River Senne collector

sewage

Full Shadow Habitat

Rock Habitat

Mountain Cave Habitat

30.00

49.00

60.00

Where Extremes Meet

120


The Horizontal Forest

Betula pendula

Place de la Monnaie

Pinus nigra

Prunus mahaleb

Section Project

Full Sun Habitat

Rock Habitat

27.00

53.00

121


The Wetland Forest Plant Community

Pinus nigra

Prunus mahaleb

Betula pendula

Quercus petraea

Asplenium trichomanis

Epipactus palustris

Asplenium adiantum

Experiencing the vertical forest from soil to camopy

Where Extremes Meet

122


123


The Mountain Forest Time Landscape

Today: Monolith towers

Buildings transformation

Mountain Pionneers

Vertical and Horizontal Growth

Where Extremes Meet

124


The Mountain Forest | Development in Time

125


A Matrix for the Forest-City

A set of design rules is defined from these case studies, exploring key urban habitats, tree communities, succession strategies and urban benefits. These guidelines can become the base for a matrix for the European Forest City.

Where Extremes Meet

126


127


A Matrix for the Forest-City

Where Extremes Meet

128


129


A Change of Attitude

Looking at the city as a potential forest territory, a new type of public space can be invented. It is a process of discoveries for a landscape that can only be met in the city: - The experience of contrasted forest habitats to be found on a very small scale. - The poetry of unknown forest communities finding there ideal landing in the most dense urban areas. - The excitement of an ever-changing picture and atmosphere in the heart of the city. The built programme will have to adapt to the specificities of these new public space creating new opportunities and challenges for architecture, urbanism and landscape architecture. A coherent green-structure can be displayed around key habitats and connect to its bigger scale surroundings. Trees First is a new attitude for urban development, where happy trees meet happy people.

Where Extremes Meet

130


131


Acknowledgement and Sources

Working on this topic, I had the chance to learn from inspiring and talented people. Many thanks to: Graduation Committee Jana Crepon | Mentor Mirjam Koevoet | Committee Member Wiebke Klemm | Committee Member Head of Landscape Architecture Maike van Stiphout Hanneke Kijne Experts Hans Kaljee | Expert Urban Forestry Marco Roos | Researcher Urban Biodiversity Michiel Mol | Expert Urban Forestry Regis Ursini | Architect Martin Knuijt | Landscape Architect Pierre-Alexandre Marchevet | Landscape Architect Friends and Family Charlotte van der Woude Koen Hezemans Antonia Cangosz Antoine Thevenet Gaila Costantini Lourdes Barrios Ayala Giuliana Sibilia Florian Fakkert Philippe Allignet Arjan Leenstra Carlijn Klomp Paul Kersten Serge van Berkel Frank Vonk Willian Vonk - de Beer Katharina von Unold Elise Gauthier Sarah Gauthier Paul Gauthier

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New Phytologist

Research

Architecture of the wood-wide web: Rhizopogon spp. genets link multiple Douglas-fir cohorts

Urban trees are thriving

Kevin J. Beiler1,2, Daniel M. Durall1, Suzanne W. Simard2, Sheri A. Maxwell3 and Annette M. Kretzer4 1

Biology and Physical Geography Unit and SARAHS Centre, University of British Columbia Okanagan, Kelowna, BC V1V 1V7, Canada; 2Department of

Forest Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; 3Department of Biology, University of Western Ontario, London, ON N6A 5B8, Canada; 4SUNY College of Environmental Science and Forestry, Faculty of Environmental and Forest Biology, One Forestry Drive, Syracuse, NY 13210-2788, USA

An explanation of the innovation of the Stockholm soil system Jonathan Nyman

Summary Author for correspondence: Kevin J. Beiler Tel: +1 250 826 1002 Email: Kevin.Beiler@gmail.com Received: 17 June 2009 Accepted: 9 September 2009

New Phytologist (2010) 185: 543–553 doi: 10.1111/j.1469-8137.2009.03069.x

Key words: ectomycorrhizas, forest stability, fungal genet, microsatellites, mycorrhizal network, Pseudotsuga menziesii (Douglasfir), Rhizopogon, stand dynamics.

• The role of mycorrhizal networks in forest dynamics is poorly understood because of the elusiveness of their spatial structure. We mapped the belowground distribution of the fungi Rhizopogon vesiculosus and Rhizopogon vinicolor and interior Douglas-fir trees (Pseudotsuga menziesii var. glauca) to determine the architecture of a mycorrhizal network in a multi-aged old-growth forest. • Rhizopogon spp. mycorrhizas were collected within a 30 · 30 m plot. Trees and fungal genets were identified using multi-locus microsatellite DNA analysis. Tree genotypes from mycorrhizas were matched to reference trees aboveground. Two trees were considered linked if they shared the same fungal genet(s). • The two Rhizopogon species each formed 13–14 genets, each colonizing up to 19 trees in the plot. Rhizopogon vesiculosus genets were larger, occurred at greater depths, and linked more trees than genets of R. vinicolor. Multiple tree cohorts were linked, with young saplings established within the mycorrhizal network of Douglas-fir veterans. A strong positive relationship was found between tree size and connectivity, resulting in a scale-free network architecture with smallworld properties. • This mycorrhizal network architecture suggests an efficient and robust network, where large trees play a foundational role in facilitating conspecific regeneration and stabilizing the ecosystem.

Introduction

Division of Landscape Architecture Department of Urban and Rural Development Master´s Thesis 30 HEC Landscape Architecture Programme – Ultuna Uppsala 2017

Mycorrhizal networks (MNs), or the mycorrhizal fungal mycelia that connect two or more plants, are increasingly recognized as mediators of interactions among trees through their effects on tree survival, growth and competitive ability (Simard & Durall, 2004; Selosse et al., 2006; Whitfield, 2007). Mycorrhizal networks provide a source of mycorrhizal fungal inoculum for establishing seedlings (Finlay & Read, 1986; Nara, 2006), and a potential conduit for interplant transfer of water, carbon and nutrients (Simard et al., 1997; He et al., 2005; Smith & Read, 2008; Warren et al., 2008). Three major challenges of MN research are determining the architecture, function and ecological significance of MNs; considerable debate exists on all levels (Whitfield, 2007). Historically, interest in MNs has focused on their formation and function in

� The Authors (2009) Journal compilation � New Phytologist (2009)

controlled artificial systems (Wu et al., 2001) and in natural ecosystems (Simard et al., 1997; Lerat et al., 2002). However, little remains known regarding the architecture of MNs in the field. Architecture includes the physical components (e.g. nodes and links) of the network and their genetic complexity, the relationships among the components, and the spatial extent and topology of the components and their relationships. Describing these attributes is a prerequisite to understanding how MNs function (e.g. in fungal colonization of plants, mycelial growth dynamics, or nutrient uptake ⁄ exchange between plants) and how they affect plant populations, communities, and forest dynamics (e.g. in tree regeneration, competition and mortality) (Nara & Hogetsu, 2004; Simard & Durall, 2004; Selosse et al., 2006). Network theory provides a useful framework for describing the structure, function and ecology of MNs (Bray, 2003;

New Phytologist (2010) 185: 543–553 543 www.newphytologist.org

Future City 9

Cecil C. Konijnendijk

Issue 1.1/2018

The Forest and the City The Cultural Landscape of Urban Woodland

Written by: Dr Andrew Hirons and Dr Henrik Sjöman

Second Edition Primary Project Funder

Academic Partners

Guidance Sponsors

TDAG

Journal of Landscape Architecture Journal of Landscape Architecture ISSN: 1862-6033 (Print) 2164-604X (Online) Journal homepage: https://www.tandfonline.com/loi/rjla20

The touch of the world: dynamic vegetation studies and embodied knowledge Roland Gustavsson To cite this article: Roland Gustavsson (2009) The touch of the world: dynamic vegetation studies and embodied knowledge, Journal of Landscape Architecture, 4:1, 42-55, DOI: 10.1080/18626033.2009.9723412 To link to this article: https://doi.org/10.1080/18626033.2009.9723412

ISSN: 1862-6033 (Print) 2164-604X (Online) Journal homepage: https://www.tandfonline.com/loi/rjla20

Urban forest and landscape infrastructure: towards a landscape architecture of openendedness Stefan Darlan Boris To cite this article: Stefan Darlan Boris (2012) Urban forest and landscape infrastructure: towards a landscape architecture of open-endedness, Journal of Landscape Architecture, 7:2, 54-59, DOI: 10.1080/18626033.2012.746089 To link to this article: https://doi.org/10.1080/18626033.2012.746089

Published online: 06 Feb 2012. Published online: 30 Nov 2012.

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Abstract

Trees First The Public Spaces of the Forest-City Master of Landscape Architecture Academy of Architecture Author Jean-François Gauthier Committee Members Jana Crepon (Mentor) Mirjam Koevoet Wiebke Klemm Amsterdam, August, 2019

Increasingly, adding trees to the city is a new goal on the urban agenda in order to fight climate change. There is an interesting contrast when looking at the average lifespan of trees in the cities: 30 years. The reason is that trees are still being seen from a utilitarian perspective and as urban furniture in European cities. As 75 per cent of the population is expected to live in an urban setting by 2050, a radical approach towards urban nature is needed. Forest should become a precondition for a healthy living and urban development. Tomorrow, we will plant forests in our cities rather than trees. Cities will adapt to forest plant communities’ needs. Space will be made for forest succession and spontaneous growth to proceed. Cities will receive great benefits in return in terms of ecosystem services, and urban forests will contribute to public health. Let’s focus on trees in the city and their needs as a starting point for a better design of public space. Let’s look at Brussels as a potential forest territory and let’s establish new public space typologies around tree communities. Forest succession will bring a new temporality in the densely populated Belgium capital. This project will take the very centre of Brussels as a case study, which is the most transformed area of the city. A hidden water system, artificial topography and remains of the initial Brussels valley define a potential forest territory. Different urban situations and very contrasted forest habitats can be found within the perimeter of our project area: the Boulevard Anspach and its surroundings. Four main forest typologies are defined: the Canyon Forest Boulevard, the Hill Forest Square, the Wetland Forest Park and the Mountain Forest Towers. A green network is built around these four forest typologies thanks to soil continuity and permeability. New urban programmes can be developed around them. A set of design rules is defined from these case studies, exploring key urban habitats, tree communities, succession strategies and urban benefits. These guidelines can become the base for a matrix for the european Forest City.

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