Timber skyline: The rise of the wooden skyscraper

Rapid urbanisation of cities is becoming more and more apparent. This immediately presents issues in terms of the carbon footprints of buildings. The bigger cities get, the taller buildings get, the more greenhouse gas emissions we produce in their construction. In order for us to make our cities bigger, taller, more environmentally-friendly, cities need to find ways to future-proof themselves.

By 2050, the global population is expected to rise to 10 billion, and around two-thirds of us will live in cities. Of course, the solution to this in terms of space will be high-rise complexes.

The materials we use now to build with, mainly concrete and steel, have a large carbon footprint. The answer may lie in something called cross-laminated timber, or CLT.

We are currently in a somewhat renaissance for timber. Wood, of course, is a renewable resource. Currently, the world’s tallest building at 53m tall is the Brock Commons Tallwood House in Vancouver, which was completed in 2017, just beating the then world’s tallest wooden building, the Treet building, at 52.8m, in Bergen. These however may be left in the proverbial timber dust, with a proposed building in Tokyo known as the W350 Project planned to reach 350m (although this is scheduled for completion in 2041).

In Brummundal, Norway, an 81m high residential building is being constructed from Norwegian timber. Vienna is currently working on an 84m high wooden building. In the Parisian district of Terne, an entire wooden building complex is under construction, and in Germany, an eight-story wooden house was built on an area that used to belong to the United States army in the Bavarian town of Bad Aibling. It is a current showpiece for energy-efficient construction.

Concrete and steel are both costly to produce and heavy to transport, whereas wood can be grown sustainably and is far lighter. Concrete manufacturing is the world’s third largest producer of greenhouse gases, and is also 15 times less thermally efficient as timber.

Another boon to using timber as a construction material is it’s ability to sequester carbon from the atmosphere as it grows, trapping that within it’s makeup. For example, Kielder Forest in Northumberland has 150 million trees. These trees sequester 82,000 tonnes of carbon annually. “This means that as a rough estimate each tree at Kielder is locking up 0.546 kg of carbon per year – equivalent to 2 kg of carbon dioxide.”

Credit: The Economist

It has been shown that a timber building can reduce it’s carbon footprint by up to 75% in contrast to a building of the same size made of conventional building materials. American architectural firm Skidmore, Owings, and Merrell (SOM) , who designed Dubai’s Burj Khalifa, have designed a 42m tower, which, if built, will have a carbon footprint 60% less than a conventional build.

“Wood environments make people happy”, gleefully asserted the exhibition ‘Timber City‘ at the National Building Museum, which ran from 2016 to 2017. The exhibition included “architectural models, a video about managed forests and a world map that highlights more than 30 notable recent wooden buildings.” There was also a selection of tree stumps, wood manufacturing examples, and different types of lumber waste, nearly all of which can be used commercially and are recyclable in some way or another.

Regular timber unfortunately isn’t malleable like steel or concrete – it cannot be poured and set as those materials can. It is not strong enough to build high. This is where CLT comes in. It is a wood-panel product made by gluing layers of solid-sawn lumber together, with each layer glued perpendicular to one another. By gluing the layers perpendicular, the finished panel achieves better structural rigidity in both directions.

Whole sections can be pre-made and erected quickly on-site. Due to the relative strength and lightness of the wood, it is also suitable for closing gaps, or construction projects on existing buildings.

In April, plans were proposed for an 300m high wooden building, consisting of 80 storeys, which would be integrated with London’s Barbican Centre, a scheme which was developed between Cambridge University’s department of architecture alongside PLP Architecture and the engineers Smith and Wallwork. The project, if realised, could create over 1,000 new residential units.

wooden-skyscraper-timber-tower-construction-roundup-designboom-02
The skyline for the proposed timber tower at the Barbican. Image: PLP Architecture / Cambridge University

“If London is going to survive it needs to increasingly densify”, says Dr Micheal Ramage, director of Cambridge’s Centre for Natural Material Innovation. “One way is taller buildings. We believe people have a greater affinity for taller buildings in natural materials rather than steel and concrete towers.”

For those of you whose immediate thought is – are we not forgetting the Great Fire of London? The fires that frequented the city of Edo (The name for 17th century Tokyo)? Fortunately for those afraid of house fires, CLT does not burn like conventional timber, as the above video will testify.

“Every well-trained firefighter knows today that an adequate solid wood construction made from cross-laminated timber will withstand fire long enough for them to rescue the residents,” said architect Tom Kaden.

Using CLT and other wooden materials offers new design potential, and ultimately, space to grow. The transition from concrete and steel to construction using timber may possibly have a wider positive impact on urban environments and build form.

It is possible that these new ideas will allow architects, designers, and engineers to reformulate the aesthetics of architecture, but also the inherent structural methodologies that architecture has generally become accustomed to. New innovations in timber could lead to a greener revolution in architecture for the 21st Century and beyond.

 

 

 

New agricultural methods increase bee populations and yields for farmers

A new strategy aimed at increasing bee populations, devised by the International Center For Agricultural Research In Dry Areas, has been put forward at the UN Biodiversity conference this week.

Global bee populations have been suffering greatly over the last few decades, such as in Germany where a 75% population decline has been seen over the last 25 years, and in Puerto Rico there has been an even sharper decline. Around 80% of food crops require pollination, but the population of insects that carry out this job, mainly bees, lessens every year.

The study recommends that a quarter of all cropland be dedicated to flowering economic crops such as oil seeds, spices, and medicinal plants. This would hopefully represent substantial gains in biodiversity. The report also mentions an increase in income across the board, but we must stress that we believe that the true measure of wealth is in natural biodiversity and the resilience of the living planet against human intrusion.

Pressure has already been put on agricultural industries by environmentalist groups for their farming procedures and intensive use of pesticides, and the responses from world governments have been increasingly varied. Just this year, Brazil’s pro-agribusiness congressmen voted for what has been dubbed as, the ‘poison package’, a lift of restrictions on an amount of pesticides that are currently banned in other countries for their detrimental impact on ecosystems.

Stefanie Christmann, who has headed up the research, has spent the last five years working on what she calls “farming with alternative pollinators”, with trials being carried in out Uzbekistan and Morocco.

“In 2013–2014, therefore, a 18-month-pilot project was set on a participatory basis in Uzbekistan, to test this farming with alternative pollinators approach on field and orchard crops. The practicability and the potential of the approach were tested in collaboration with seven smallholders, two commercial farmers, and two schools. “

“We analyzed the yield and insect diversity (pollinators, predators, and pests) of seven cucumber fields in the Parkent district and four orchards of sour cherry in the Boysun district in Uzbekistan. Here we show that the fields with enhanced habitats faced higher diversity of pollinators and predators, but less pests than control fields. Furthermore, the farming with alternative pollinators approach doubled the yield of sour cherry in 2014 and highly increased the income from cucumber in 2013. “

The technique that Christmann proposes represents an agricultural method closer to the formation of natural green areas such as forests, in constrast to intensive monoculture farming already in place. One in every four cultivation strips should be dedicated to the aforementioned flowering crops. Nesting support for bees and other insects should also be provided to encourage populations to thrive, support such as old wood and beaten soil that can be burrowed into.

“There is a very low barrier so anyone in even the poorest country can do this. There is no equipment, no technology and only a small investment in seeds. It is very easy. You can demonstrate how to do it with pictures sent on a cellphone.”

Ultimately, 94% of the farmers were willing to enhance pollinator habitats after being informed of these higher-yield figures.” During the test periods, the efficiency of crop pollination was increased, and the amount of pests was significantly lower.

The greatest gains in the four differing climatic regions that Christmann studied were found in semi-arid climates, where pumpkin yields rose 561%, aubergine 364%, broad bean 177% and melons 56%. In rainier areas, the harvests of tomatoes doubled in size, and aubergines harvests increased by 250%.

There are many environmental and economic benefits to increasing the amount of wild pollinators by encouraging the planting of more diverse crop rotations. This can also be applied to cities, where the planting of wildflowers, berry bushes, and flowering trees can aid in biodiversity.

“The entire environment would be richer, more beautiful and more resilient to climate change,” said Christmann “We would have many more insects, flowers and birds. And it would be far more self-sustaining. Even the poorest countries in the world could do this.”

It is hoped that there may be, in the near future, support for a multilateral environmental agreement on the wellbeing and promotion of natural pollinators, similar to the international convention on trade in endangered species.

But there will be resistance, Christmann admits “I think Monsanto won’t like this because they want to sell their pesticides and this approach reduces pests naturally,”.

Christmann’s research comes as part of a growing campaign to change the very nature of global food production. In the ‘Ecological Farming versus Industrial Agriculture’ section of Greenpeace’s ‘Plan Bee – Living Without Pesticides’ report, it is written:

“Agricultural intensification in Europe has typically led to more homogeneous landscapes, defined by large cereal fields and a loss of non-cultivated habitats on farms – such as hedgerows, ditches, woodland, and field margins. In addition, there has been widespread loss of semi-natural grasslands due to their conversion into arable fields and coniferous tree plantations (Meeus et al. 1990). Semi-natural habitat loss and degradation on farms and in surrounding areas, together with the increased use of agrochemicals such as synthetic pesticides, has been linked to a loss of wildlife species in agricultural landscapes (Belfrage 2005).”

Things are looking a little brighter, with a recent EU-wide ban on bee-harming neonicotinoids. “Bee health remains of paramount importance for me since it concerns biodiversity, food production and the environment.” Said Vytenis Andriukaitis, European commissioner for Health and Food Safety, after he welcomed the vote.

On organic, pesticide-free farming, Giannis Melos, a farmer from Greece, had this to say: “In the past I have used plenty of chemicals as a conventional producer, but when I started farming organically only then I realised how many mistakes I had made in the past and that I had been trying to fight the symptom and not the cause. […] With the balance brought about by organic farming there are many benefits in your cultivation. You can see that the soil is more lively, you can see the organisms that form the surrounding environment being in a balance that is not disrupted. Of course there are benefits for the planet, because the residues from chemicals take many years to degrade.”