Circular Economy

Wood: An Economy of Cycles

Not only is wood a wonderful construction material, with more and more architects, buildings owners, and engineers recognizing its possibilities and advantages. Wood is also a truly genius invention of nature: The more wood we use, the more the environment and nature profits.

The non-renewable resources of our planet keep decreasing at the same pace as the number of global consumers trying to see their demands fulfilled keeps increasing. This mainly relates to energy, which is needed to produce construction material just as much as it is for driving cars, heating apartments, or air travel. We all know: The energy we use today is the energy our children will not have tomorrow. And: The energy we use today is changing the climate of tomorrow.

This rule is true for almost every product, but it is not true for wood. Nature has bestowed extraordinary traits on this renewable resource. Its production uses abundantly available base substances: sunlight and carbon. Nature’s ingenious growth process infuses the wood of the trees with free energy from the sun. At the same time, carbon, which otherwise only contributes to the further warming of our atmosphere (as CO2), is absorbed. Nature makes it possible to produce over a cubic meter of wood with a ton of CO2, saving around 2,800 kWh of solar energy in the process.

[Picture 01: Wood as a CO2 sink]



The Positive Paradox of Wood

One ton of CO2 results in over a cubic meter of wood. This process results in a phenomenon that sets wood apart from almost every other composite and construction material: The more we wood we take from sustainably managed forests, the more our environment profits. As trees grow and regrow, they keep consuming CO2 (mainly entering our atmosphere through the burning of fossil fuels).

But it is not only the trees regrowing in the forests which serve as CO2 sinks – but also whatever is created from them. A building, a bridge, a fence, or a piece of furniture made of wood thus are much more than just beautiful structures or articles of daily use. They too are CO2 deposits, storing greenhouse gases often for a very long time.

The forest and timber industry handle this brilliant resource with care. None of the biomass harvested in the forest goes to waste, as all of it is put to use. Large roundwood is processed into sawn timber, which in turn is used to produce construction material, but also panels, slats, furniture, and so on. Thinner timbers and raw wood chips, leftovers from the production process, are used as base material for composite panels. Bark and wood shavings are excellently suited as fuel, covering most of the energy demand of sawmills (e.g. for the drying facilities) or paper mills. 

[picture 02 Wood Life Cycle] 

A Brilliant Climate and Energy Balance

Due to the low primary energy demand for the production of wood products, wood as a composite and construction material compares very well to other materials produced on an industrial scale with much higher energy demands. This means that the environment profits double when a house is built with wood instead of other materials: By storing CO2 in every cubic meter used and by saving CO2 in production, avoiding greenhouse gas emissions that otherwise would have resulted from the use of fossil fuels in the production process of conventional construction materials. On top, a house built with wood saves CO2 over its entire lifetime, as timber is very well suited for energy-efficient buildings with substantially less greenhouse gas emissions per heating period.

Many construction materials made from timber have a second use after their “first life”, such as serving as base material for boards. And at the very end, wood can still be used for heating. When being burned, the stored solar energy is released along with the exact same amount of carbon dioxide that was used for the wood’s growth. At this point, the perfect cycle of the resource wood is complete.


Credits

Text: Joachim Brauer, Bad Segeberg, Lignum – Holzwirtschaft Schweiz

Bilder und Grafiken

No.CaptionCredits
01 Solar energy  
02Life cycle of wood  
03 Timber harvesting   
04 Loading   
05 Debarking of roundwood  
06 Wood cutting  
07 Desiccation   
08 Production in the workshop  
09 On-site delivery  
10 Woodworking residues  
11 Raw material for production  
12 Recycling   
13 Oriented Strand Board OSB  
14 Shutters ready for processing