Sustainable, renewable, and beneficial for the environment: Wood is the future’s material. But how much wood do we really have, and how can we utilize it effectively? Recent research has meticulously examined the wood flows in Switzerland and identified untapped potential.
Switzerland has ambitiously aimed for net zero emissions by 2050. Wood is a crucial raw material in achieving a climate-neutral future. This renewable resource captures CO2 from the atmosphere during its growth. It serves as both a material and an energy source, providing alternatives to fossil fuels. Consequently, various industries, including construction, textiles, electronics, chemicals, and pharmaceuticals, are planning to increase their reliance on wood in the future.
However, there is limited knowledge about the available wood for these intended uses and its forms. To address this, researchers from Empa and WSL have thoroughly examined all documented wood flows in Switzerland. Their findings were recently published in the journal Industrial Ecology as part of SCENE, a joint initiative within the ETH Domain (see box).
Comprehensive Data for Precise Evaluation
In their assessment, the researchers utilized data from 2020 sourced from 21 different references. This posed a methodological challenge, as the numbers did not always align across these sources. Wood is a versatile raw material, appearing in various forms throughout its journey from harvest to consumption, differing in size and moisture levels: raw timber, sawn wood, wood chips, wood pulp for paper, and more. Aligning these different material flows was a significant challenge.
Yet the effort proved worthwhile. “International comparable studies often rely on models. They gather data on how much wood is cut in forests and use that to estimate further material flows,” explains Nadia Malinverno, lead author of the study from Empa’s Technology and Society lab. Conversely, the Empa team primarily employed “actual” data ranging from timber harvesting and trade to processing, recycling, and disposal. This approach yields a more precise understanding — though not flawless, as Malinverno notes. “We owe gratitude to our colleagues at WSL and the Federal Office for the Environment (FOEN) for providing quality data available in Switzerland,” adds co-author and Empa researcher Claudia Som.
Maximizing Wood’s Lifespan
The findings indicate that Switzerland has substantial room for improving the sustainable usage of wood. For instance, the recycling rate for wood is slightly under eight percent, whereas the rate for paper is around 70 percent. Additionally, “Of the five to seven million cubic meters of wood harvested in Switzerland annually, approximately 40 percent is directly used for energy production — essentially being burned,” states Malinverno. The researchers argue that this practice is not optimal. “For wood to act as a long-lasting CO2 store, it should be maintained in the technosphere as a material for as long as possible,” explains Som.
The researchers and the SCENE initiative advocate for a method of utilizing wood known as cascading use. In this model, a harvested tree would first be transformed into the largest possible high-quality product — such as beams and boards for construction. This wood should then be reused in its primary role for as long as practical. Only when reuse is impractical should the wood be broken down into smaller materials, like smaller boards, wood chips, or wood composites. It should only be incinerated when it has exhausted its material uses.
This is one example of a wood cascade. As part of SCENE, the researchers plan to further explore which wood uses are most effective from both ecological and economic viewpoints. Their objectives include a closer investigation into selected wood flows: What forms does wood take in a specific flow? Where is it produced? How is it processed? And what alternative uses could be possible? Over the next few years, Nadia Malinverno, Claudia Som, and their colleagues will be looking into these questions.
