̽��ֱ�� of Cambridge - Faculty of Architecture and History of Art

Sowing seeds for timber skyscrapers can rewind the carbon footprint of the concrete industry

ehs33 — Fri, 28 Jun 2019 12:51:58 +0000

Recent innovations in engineered timber have laid the foundations for the world’s first wooden skyscrapers to appear within a decade, a feat that is not only achievable—according to the Centre for Natural Material Innovation—but one they hope will beckon in an era of sustainable wooden cities, helping reverse historic emissions from the construction industry.

̽��ֱ��research team based at the Faculty of Architecture, is interdisciplinary, composed of architects, biochemists, chemists, mathematicians and engineers, who specialise in plant-based material, including cross-laminated timber, arguably the first major structural innovation since the advent of reinforced concrete, 150 years ago.

Principal Investigator Dr Michael Ramage, said “Until cross-laminated timber, there was simply no building material to challenge steel or reinforced concrete. To construct cities and indeed skyscrapers, we just had to accept the good and the bad of existing materials.

“Concrete is about five times heavier than timber, which means more expense for foundations and transport; it’s resource-intensive, and contributes to tremendous carbon dioxide emissions. After water, concrete is the most consumed material by humanity. But now we have an alternative, and it’s plant-based.”

̽��ֱ��team envisage trees supplanting concrete as the predominant building material for cities, with buildings sown like seeds and cities harvested as crops, a way of simultaneously addressing climate change and global housing shortages.

Dr Ramage explained: “In England alone, we need to build 340,000 new homes each year over the next 12 years to accommodate our population. Concrete is unsustainable. Timber, however, is the only building material we can grow, and that actually reduces carbon dioxide. Every tonne of timber expunges 1.8 tonnes of carbon dioxide from the atmosphere. Doing the calculations, if all new English homes were constructed from timber, we could capture and offset the carbon footprints of around 850,000 people for 10 years.

“ ̽��ֱ��sustainable forests of Europe take just 7 seconds to grow the volume of timber required for a 3 bedroom apartment, and 4 hours to grow a 300 metre supertall skyscraper. Canada’s sustainable forests alone yield enough timber to house a billion people in perpetuity, with forested trees replenishing faster than their eventual occupants.”

Various teams around the world are hoping to produce the tallest wooden skyscraper, however the team from Cambridge is confident they’ll be the first, having done holistic work on three proposals for timber skyscrapers in London, Chicago, and the Hague, all of which are set to be showcased to the public at the Royal Society’s Summer Science Exhibition 2019, freely open to the public from July 1–7.

̽��ֱ��team’s exhibit—Timber towers of tomorrow—will embody their vision, the stand itself modelled after a typical apartment nested within their proposed Oakwood Timber Tower at the Barbican Tower, where visitors can experience life in a treehouse while talking with the team, viewing architectural models of timber towers, learning about the fire performance properties of engineered timber, and hearing about the genetic, cellular, and macroscale innovations which have led to ply in the sky designs becoming a reality.

Beyond tackling climate change and promoting sustainability, the team are eager to outline the branching benefits society stands to gain by embracing timber architecture: the psychological well-being that comes from being surrounded by wood as compared with concrete, as well as the return to an ancient building material, that’s intimate as it is natural.

A bold response to the world’s greatest challenge
̽��ֱ�� ̽��ֱ�� of Cambridge is building on its existing research and launching an ambitious new environment and climate change initiative. Cambridge Zero is not just about developing greener technologies. It will harness the full power of the ̽��ֱ��’s research and policy expertise, developing solutions that work for our lives, our society and our biosphere.

̽��ֱ��Centre for Natural Material Innovation exhibited their proposals for timber skyscrapers at the Royal Society’s Summer Science Exhibition.

Wooden skyscrapers: Sustainable homes of the future?

River Beech Tower Chicago

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Wrong trees in the wrong place can make cities hotter at night, study reveals

ta385 — Tue, 10 Dec 2024 09:45:00 +0000

Temperatures in cities are rising across the globe and urban heat stress is already a major problem causing illness, death, a surge in energy use to cool buildings down, heat-related social inequality issues and problems with urban infrastructure.

Some cities have already started implementing mitigation strategies, with tree planting prominent among them. But a ̽��ֱ�� of Cambridge-led study now warns that planting the wrong species or the wrong combination of trees in suboptimal locations or arrangements can limit their benefits.

̽��ֱ��study, published today in Communications Earth & Environment found that urban trees can lower pedestrian-level air temperature by up to 12°C. Its authors found that the introduction of trees reduced peak monthly temperatures to below 26°C in 83% of the cities studied, meeting the ‘thermal comfort threshold’. However, they also found that this cooling ability varies significantly around the world and is influenced by tree species traits, urban layout and climate conditions.

“Our study busts the myth that trees are the ultimate panacea for overheating cities across the globe,” said Dr Ronita Bardhan, Associate Professor of Sustainable Built Environment at Cambridge's Dept. of Architecture.

“Trees have a crucial role to play in cooling cities down but we need to plant them much more strategically to maximise the benefits which they can provide.”

Previous research on the cooling effects of urban trees has focused on specific climates or regions, and considered case studies in a fragmented way, leaving major gaps in our knowledge about unique tree cooling mechanisms and how these interact with diverse urban features.

To overcome this, the authors of this study analysed the findings of 182 studies – concerning 17 climates in 110 global cities or regions – published between 2010 and 2023, offering the first comprehensive global assessment of urban tree cooling.

During the day, trees cool cities in three ways: by blocking solar radiation; through evaporation of water via pores in their leaves; and by foliage aerodynamically changing airflow. At night, however, tree canopies can trap longwave radiation from the ground surface, due to aerodynamic resistance and ‘stomatal closure’ – the closing of microscopic pores on the surface of leaves partly in response to heat and drought stress.

Variation by climate type

̽��ֱ��study found that urban trees generally cool cities more in hot and dry climates, and less in hot humid climates.

In the ‘tropical wet and dry or savanna’ climate, trees can cool cities by as much as 12 °C, as recorded in Nigeria. However, it was in this same climate that trees also warmed cities most at night, by up to 0.8°C.

Trees performed well in arid climates, cooling cities by just over 9°C and warming them at night by 0.4 °C.

In tropical rainforest climates, where humidity is higher, the daytime cooling effect dropped to approximately 2°C while the nighttime heating effect was 0.8 °C.

In temperate climates, trees can cool cities by up to 6°C and warm them by 1.5°C.

Using trees more strategically

̽��ֱ��study points out that cities which have more open urban layouts are more likely to feature a mix of evergreen and deciduous trees of varying sizes. This, the researchers found, tends to result in greater cooling in temperate, continental and tropical climates.

̽��ֱ��combined use of trees in these climates generally results in 0.5 °C more cooling than in cities where only deciduous or evergreen trees feature. This is because mixed trees can balance seasonal shading and sunlight, providing three-dimensional cooling at various heights.

In arid climates, however, the researchers found that evergreen species dominate and cool more effectively in the specific context of compact urban layouts such as Cairo in Egypt, or Dubai in UAE.

In general, trees cooled more effectively in open and low-rise cities in dry climates. In open urban layouts, cooling can be improved by about 0.4 °C because their larger green spaces allow for more and larger tree canopies and a greater mix of tree species.

“Our study provides context-specific greening guidelines for urban planners to more effectively harness tree cooling in the face of global warming,” Dr Ronita Bardhan said.

“Our results emphasize that urban planners not only need to give cities more green spaces, they need to plant the right mix of trees in optimal positions to maximize cooling benefits.”

“Urban planners should plan for future warmer climates by choosing resilient species which will continue to thrive and maintain cooling benefits,” said Dr Bardhan, a Fellow of Selwyn College, Cambridge.

Matching trees to urban forms

̽��ֱ��study goes further, arguing that species selection and placement needs to be compatible with urban forms. ̽��ֱ��orientation of the ‘street canyon’, local climate zones, aspect ratio, visible sky ratio and other urban features that influence the effects of trees all need to be carefully considered.

Although a higher degree of tree canopy cover in street canyons generally results in more cooling effects, excessively high cover may trap heat at the pedestrian level, especially in compact urban zones in high temperature climates. In such locations, narrow species and sparse planting strategies are recommended.

̽��ֱ��researchers emphasise that we cannot rely entirely on trees to cool cities, and that solutions such as solar shading and reflective materials will continue to play an important role.

̽��ֱ��researchers have developed an interactive database and map to enable users to estimate the cooling efficacy of strategies based on data from cities with similar climates and urban structures.

Reference

H Li et al., ‘Cooling efficacy of trees across cities is determined by background climate, urban morphology, and tree trait’, Communications Earth & Environment (2024). DOI: 10.1038/s43247-024-01908-4

While trees can cool some cities significantly during the day, new research shows that tree canopies can also trap heat and raise temperatures at night. ̽��ֱ��study aims to help urban planners choose the best combinations of trees and planting locations to combat urban heat stress.

Trees have a crucial role to play in cooling cities down but we need to plant them much more strategically to maximise the benefits which they can provide

Ronita Bardhan

hannahisabelnic via Flikr (Public domain)

Trees in an Indian city street. Photo: hannahisabelnic via Flikr (Public domain)

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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A retrofitting revolution

cg605 — Thu, 06 Oct 2022 12:01:37 +0000

Laying the foundations for buildings to stay cool in extreme heat.

Bamboo bats... Howzat?!

ta385 — Mon, 10 May 2021 05:00:00 +0000

Cricket bats should be made from bamboo rather than traditional willow, say researchers from Cambridge’s Centre for Natural Material Innovation. Extensive tests showed that bamboo performs better than willow as well as being more sustainable and cheaper.

Digital resurrection: bringing one of Italy's most important lost churches back to life

ta385 — Mon, 03 Aug 2020 11:30:00 +0000

Art historians have created a new app which allows users to roam around one of Florence’s oldest and most important churches, San Pier Maggiore, 240 years after it was demolished.

Cambridge academics elected to British Academy fellowship

Anonymous — Mon, 27 Jul 2020 12:49:00 +0000

They are among 86 distinguished scholars to be elected to the fellowship in recognition of their work in the fields of law, economics, Middle Eastern studies, geography, history of science, art and architecture, classics, and English literature.

̽��ֱ��Cambridge academics made Fellows of the Academy this year are:

Professor Catherine Barnard (Faculty of Law; Trinity College) has been elected to the fellowship in recognition of her work on European Union law, especially the single market; Brexit and the UK-EU future relationship; employment law, especially equality law, and its European dimension.
Professor Giancarlo Corsetti (Faculty of Economics; Clare College) has been elected to the fellowship in recognition of his work in the field of economic policy and international economics, with focus on currency, financial and debt crises, European monetary union and open economy macroeconomics.
Professor Khaled Fahmy (Faculty of Asian and Middle Eastern Studies; King's College) has been elected to the fellowship in recognition of his work on modern Middle Eastern history, history of Islamic law, the Arab-Israeli conflict.
Professor Sarah Radcliffe (Department of Geography; Christ's College) has been elected to the fellowship in recognition of her work on critical development and political geography; postcolonial and decolonial geography; indigeneity; intersectionality in socio-spatial inequalities; these themes in relation to Andean lives, contestations and knowledges.
Professor James Secord (Department of History and Philosophy of Science; Christ’s College) has been elected to the fellowship in recognition of his work on history of science; science communication; natural history, evolution and geology in the 18th and 19th centuries.
Professor Caroline van Eck (Department of History of Art; King’s College) has been elected to the fellowship in recognition of her work on the history of European art and architecture c. 1800 in a globalising world.
Professor Timothy Whitmarsh (Faculty of Classics; St John's College) has been elected to the fellowship in recognition of his work on ancient Mediterranean literature, culture and thought; Greek literature, especially of the Roman Empire; cultural contacts in the ancient world; ancient religion and scepticism; literary and cultural theory.
Professor Clair Wills (Faculty of English; Murray Edwards College) has been elected to the fellowship in recognition of her work on 20th-century British and Irish cultural history; contemporary writing; the literature and social history of migration.

̽��ֱ��British Academy has also welcomed four new honorary Fellows, among them Bridget Kendall MBE, Master of Peterhouse Cambridge. Kendall is a broadcaster and writer with a particular interest in Russia, international diplomacy and security and promotion of language learning.

̽��ֱ��new Fellows join a community of over 1,400 leading minds that make up the UK’s national academy for the humanities and social sciences. Current Fellows include the classicist Professor Dame Mary Beard, the historian Professor Sir Simon Schama and philosopher Professor Baroness Onora O’Neill, while current honorary Fellows include Dame Joan Bakewell, Sir Tim Berners-Lee and Baroness Brenda Hale.

Professor Whitmarsh said: “I have owed much, along the way, to the British Academy, who funded my postgraduate studies and awarded me a Mid-Career Fellowship in 2012-2013, which allowed me to write my book Battling the Gods. I am now greatly honoured, and genuinely humbled, to have been elected a Fellow.”

Professor Sir David Cannadine, President of the British Academy, said: "I would like to extend a warm welcome and hearty congratulations to the individuals who have joined the British Academy Fellowship. This is a time to reflect on the many invaluable contributions these academics have made to their disciplines. It is also a time for celebration, and I hope that, social distancing measures notwithstanding, each of our new Fellows is able to do so in ways great or small."

As well as a fellowship, the British Academy is a funding body for research, nationally and internationally, and a forum for debate and engagement.

Eight academics from the ̽��ֱ�� of Cambridge have been made Fellows of the prestigious British Academy for the humanities and social sciences.

I have owed much, along the way, to the British Academy ... I am now greatly honoured, and genuinely humbled, to have been elected a Fellow

Timothy Whitmarsh

̽��ֱ��British Academy

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Life-saving origami

ta385 — Tue, 21 Apr 2020 12:30:12 +0000

Cambridge researchers are sharing a quick and easy way to mass produce face shields for health workers in the poorest countries.

Fixing India’s slum rehabilitation housing

ta385 — Thu, 13 Feb 2020 08:00:00 +0000

Millions of new houses being built for former slum-dwellers are failing their residents and fuelling unnecessary energy use. New research aims to improve their design before it’s too late.