The growing assumption that buildings should not only be sustainable, but also have a positive impact on their surroundings, is forcing the search for new technologies and materials. The answer to part of the challenge of reducing the destructive role of building on the environment is supposed to be the development of wooden architecture. But is wood really a sustainable material?
Although the thesis that sustainability is not enough is reaching the architectural mainstream with considerable delay, avant-garde building technologies are often beginning to take on the role previously assigned to the icons coming off the drawing boards of starchitects. More countries, companies and architectural firms are outdoing themselves in building the tallest, largest, most technologically advanced skyscrapers out of wood. Such buildings are intended by their authors to have limited environmental impact, a reduced carbon footprint, and responsible stewardship of raw materials written into their DNA.
production chain
Photo: Peter Fiskerstrand / Wikimedia Commons
It's not just about the use of the building itself - the entire architectural production chain from design to operation becomes important. What is important is where the raw materials for the materials are sourced from and how they are manufactured, processed, and the used materials are disposed of and recycled.
Photo: Øyvind Holmstad / Wikimedia Commons
One of the trends in contemporary architecture that is starting to enter the implementation phase more and more boldly is wooden structures. Until recently mainly associated with traditional architecture, swimming pools and sports arenas, today they are considered by many experts to be the future of residential construction. In 2019, the Mjøstårnet in Brumunddal, Norway, was completed. The over 85-meter-high tower designed by Voll Arkitekter, in addition to concrete ceilings, is almost entirely made of glulam - from the superstructure to the elevator shafts to the stairs and trim.
Japan's tallest
W350 in Tokyo
photo: Sumitomo Forestry Co
Meanwhile, a 350-meter-tall skyscraper is already being planned in the Japanese capital with a hybrid structure made of 90 percent wood. It will become the country's tallest building. The construction itself will be a testing ground - designed jointly by architects and specialists associated with the production of engineered wood (Nikken Sekkei and Sumitomo Forestry Tsukuba Research Institute), it is likely to become a symbolic opening of a new chapter in Japanese modern architecture. Constructing skyscrapers out of wood presents many challenges. Still, the technology remains more expensive than traditional steel and concrete structures. Quite a different approach is required for fire safety, structural deflection and corrosion protection, or finishing elements.
W350 in Tokyo
photo: Sumitomo Forestry Co
deforestation
In the discussion of new ways to use wood, however, it is worth asking the question - where do the raw materials for glued-laminated beams and ceilings come from. Maximizing the use of wood in residential and commercial construction can help clean the atmosphere of some 21 million tons of CO2 per year - equivalent to the emissions from 4.4 million cars. Just isn't reducing greenhouse gas production at the expense of extensive deforestation? As the WWF report indicates, the amount of timber harvested is expected to triple by 2050. Such large cuttings are caused by demand coming from the bioenergy, pharmaceutical and cosmetics or textile industries.
more and more logging
Increasing area of logging
photo: Nature
Although it may seem that Poland is an intensively forested country, its forests, which cover about 30 percent of the country's area, rank us only 19th in the European Union. Although the annual increase in timber harvesting in EU countries is about 1.5 percent (2.6 percent in Poland), when comparing data from longer periods, the increments reach significant values. To compare, between 2004-2015 and 2016-2018, we got a 24 percent increase in logging in Poland (compiled by forest-monitor.com). The problem, in addition to the sheer scale of the harvesting, is its location. For the timber does not come only from crops and artificial afforestation, but more and more often the victims of harvesters are primeval forests - Białowieża or Karpacka. In this way, entire ecosystems and habitats of animals and plants are destroyed. No new plantings can compensate for this loss.
speculation
photo by Rafał Chudy - forest-monitor.com
The problem with the volume of timber harvesting is also pointed out by industry institutions. They are struggling with the problem of speculation on the market. This is caused, among other things, by the huge demand from the Chinese industry and other European countries, which have already introduced mechanisms to restrict exports of their own timber, after the price of the raw material hit its highest level ever. Chambers of commerce and associations have been calling for a ban on exports related to the timber industry since 2017.
sustainable cultivation
photo by Rafal Chudy - forest-monitor.com
Thestigma on the environment is imprinted by every design decision. So is the use of wood a way to reduce the negative effects of the architecture industry? It seems that despite problems with sourcing, wood remains a more environmentally friendly material than concrete, steel or aluminum. Assuming, however, that structural timber comes from certified crops, animal rights and natural ecosystems can be safeguarded in this way. Such cultivation, however, must not replace natural forests, but only be carried out on previously unforested land.
environmental impact
Photo: Soil-Science.info / Wikimedia Commons
Timber production itself can have a positive impact on the environment, thanks to photosynthesis, which reduces the level of CO2 contained in the atmosphere. Carbon sequestration (i.e. carbon capture and storage) is more efficient in the early stages of plant growth, and so can be used in sustainable tree crops. The embodied carbon level for wood is about 180 kg CO2/m³, and for concrete 240 kg CO2/m³. However, it should be remembered that these materials require different types of construction which consumes different amounts of materials.
The level of so-called embodied energy is also important. Embodied energy is the total energy required for extraction, processing, production and delivery of construction materials. Unlike a life-cycle assessment, which evaluates all impacts over the life of a material or component, embodied energy takes into accountno handling or disposal of materials. Wood, with values of around 3.4-6.0 GJ/m²,performs significantly better than brick (6.5-29 GJ/m²), the concrete component cement (16.4 GJ/m²) or steel (70-270 G J/m²)(source).
As scientific studies suggest, completely replacing other construction materials with wood would reduce CO2 emissions between 14 and 31 percent and fossil fuel consumption between 12 and 19 percent(source).
It can be predicted that the coming years in architecture will bring further development of green solutions related to wood construction and expansion of technological adaptability of existing structures. Increasing awareness of environmental and social burdens will force new solutions already at the stage of design and production of materials, and a new look at common spaces can bring surprising visual and functional results.
