When Trees Meet Buildings | The B1M

In an effort to create a more pleasant, healthier and sustainable built environment, architects, engineers and developers are creating increasingly.


In an effort to create a more pleasant, healthier
and sustainable built environment, architects, engineers and developers are creating increasingly greener structures and doing it in a more literal way than ever before. This is what happens when trees meet buildings. Buildings with trees are actually nothing
new. The mythical Hanging Gardens of Babylon are often imagined as a stepped palace of
terraces containing numerous trees, shrubs and exotic flowers. Although no such building was found during
excavations in Mesopotamia, and its existence has been subject to much debate, artists have
kept this imagery alive in their paintings throughout the centuries. The current revival of green architecture
began in the 1970s, when the energy crisis, coupled with growing awareness of humankind’s
impact on the environment, propelled architects and engineers to think more carefully about
sustainable development. Although there are many different ways
to approach sustainable building design, an increasing number of architects and engineers
began to incorporate green roofs and other energy saving measures into their projects. A prominent example of this is the Willis
Faber and Dumas Headquarters in Ipswich in the United Kingdom, designed by Sir Norman
Foster and completed in 1975. The building features a reflective double-leaf
facade and a grass-covered roof, which could be used as breakout space for the firm’s
employees. Other approaches advocate integrating trees
and plants within buildings, often to soften the psychological impact of living in modern
cities. One of the most idiosyncratic proponents of this approach was Austrian artist Friedensreich Hundertwasser, who designed an apartment building and a number of hotels throughout the 1980s and 90s incorporating mature trees in Vienna and elsewhere across his native country. Since then, research has demonstrated that
green space can have a substantial physical and psychological impact on our urban environments. Studies have shown that even a small park can reduce local surface temperatures by as much as 7 degrees Celsius, while urban trees planted along streets can reduce temperatures by up to 3.9 degrees Celsius. Green roofs also perform well their temperatures can be as much as 4.4 degrees
Celsius cooler than conventional roof finishes and – if used across an urban area – could
reduce temperatures by as much as 7 degrees Celsius. The benefits of temperature regulation can
also be found in deciduous trees, which offer passive solar shading in the summer, while
allowing the sun’s rays to penetrate deep into a building’s floor plan during winter
months. Trees can also reduce the amount of exhaust
gases and particles in the air, with some studies claiming that they help reduce
local concentrations of nitrogen oxide by up to 57%. Aside from their physical impact, there is
powerful evidence that the inclusion of plants within our built environment can deliver psychological
benefits too. Hospital patients with views of green spaces
have had faster recovery times and plants have been shown to reduce stress amongst office
workers, which in turn increases their productivity. This can often lead to extensive planting
being added to existing structures, either as a way to replace lost habitats or decrease
urban island heat effect, or to create green spaces for the benefit of people living and
working in dense urban areas. Projects of this kind include Chicago’s
green roofs project launched in 2001, as well as linear parks, such as the 1993 Promenade Plantee in Paris This was the precursor to the hugely popular High Line that now occupies a disused elevated freight railway in Manhattan, which first opened in 2009 and Thomas Heatherwick’s unrealised Garden Bridge in London, proposed in 2013. Arguably more exciting is the growing trend
of integrating entire trees into built structures – leading to increasingly ambitious projects
with deep, strategically placed planters that provide enough space for tree roots to develop. One of the most impressive examples of this
is ACROS, a cultural centre in Fukuoka, Japan. First opened to public back in 1995, this
14-storey building designed by Emilio Ambasz steps down to meet the city’s Tenjin Central
Park. The building contains deep planters alongs the edges of its terraces that allow trees to take root and grow. Its 5,400 square metres (or 58,000 square feet) of greenery contained some 37,000 plants representing 76 different species when it first completed. Today, it contains more than 120 varieties
of plant and over 50,000 individual specimens. Architectural office MVRDV took a similar
approach when designing the Netherlands’ pavilion for the 2000 Expo in Hanover, Germany. Here, the entire fifth floor of the structure
was given over to a ‘forest’ in which deep planters accommodated mature trees. Although the structure has since fallen into
disrepair, with the mature trees dying off, a new generation of shrubs and trees has since colonised the structure proving the soundness of the principle Later in the decade, architecture and engineering firm WOHA designed the Royal Pickering Hotel in Singapore, which included extensively planted
terraces at four storey intervals featuring tropical shrubs, vines and palm trees. This building completed in 2013, just a year
before the twin towers of “Bosco Verticale” or the “Vertical Forest” in Milan. Conceived by Stefano Boeri Architects, these residential towers – standing 112 metres and 76 metres tall respectively in central Milan – are the first successful example of tall buildings fully covered in trees. Standing between 3 and 6 metres tall when they were first planted, the trees will be allowed to reach maximum height of 9 metres
before being pruned. In order to ensure their stability in the wind, the trees are tethered to the building using steel wires Structurally, buildings that incorporate trees
will of course require special consideration and additional strengthening and reinforcement
in areas. In the case of Bosco Verticale the additional
cost of this reinforcement was clearly offset by benefits and did not prevent the project
proceeding. There are other issues to consider when mixing
trees with buildings too – such as the embodied carbon of the steel used in reinforcement
or building superstructures and the increased demands placed on maintenance. In this example, the project team were able
to use Milan’s excess underground water to cultivate the trees, minimising the towers’
ecological footprint. Another challenge posed by this new building
type, with large amounts of potentially flammable organic matter attached to facades, is fire. Principally, engineers use established guidelines
for green facades and green roofs to ensure their buildings meet fire safety regulations. Regular pruning and irrigation also help to
mitigate the risk of fire, as does ensuring that the soil contains a relatively low percentage
of organic matter. Learning from his work in Milan, Stefano Boeri
is currently working on a number of similar projects in places such as Switzerland, China
and the Netherlands. The concept of incorporating trees into buildings
is also employed across South-East Asia and features heavily in the work of Vietnamese
studio Vo Trong Nghia – who have incorporated trees into buildings as diverse as private
residences through to a university office in Hanoi Currently under construction in Taipei, Belgian
architect Vincent Callebaut’s Agora Tower, based on the form of a DNA double helix, will
feature extensively planted balconies. Meanwhile in Shanghai, British designer Thomas
Heatherwick’s 1,000 Trees, a mixed-use building that features trees and shrubs on
its structural columns is nearing completion …and in the UK, Heatherwick’s Maggie’s
Center in Leeds uses its roofs to create a stepped garden, complete with trees and lush
vegetation. In Singapore, WOHA continue to design green
architecture, including the Oasia Hotel Downtown, a 27-storey tower that features a trellis-like facade and three large sky terraces with swimming pools and palms This innovative structure was named “Best
Tall Building Worldwide” in 2018 by the Council on Tall Buildings and Urban Habitat. The designers and engineers working on the latest generation of treescrapers have also
decided to tackle the issue of embodied carbon and the considerable amounts of energy consumed
when manufacturing steel and concrete. Increasingly, carbon-negative materials such
as Cross Laminated Timber (CLT) or glue laminated timber, commonly known as glulam, are being
used. High rise structures such as the proposed
18-storey Tree Tower Toronto by Penda or this 350 metre tall theoretical proposal for Sumitomo Forestry’s headquarters in Tokyo by Nikken Sekkei demonstrate the continually
growing trend of incorporating trees into buildings and the work of today’s architects
and engineers to push this concept to its very limits If you enjoyed this video and would like to get more from the definitive video channel for construction subscribe to The B1M.

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