‘Tree bark is an underutilised resource’
Charlett WenigProfession:
Materials scientist and industrial designer
Position:
Post-doc at the Max Planck Institute of Colloids and Interfaces in Potsdam
Profession:
Materials scientist and industrial designer
Position:
Post-doc at the Max Planck Institute of Colloids and Interfaces in Potsdam
Charlett Wenig is researching the potential of tree bark to establish this previously little recognised raw material as a biomaterial for new applications.
Wood is a sought-after raw material. However, the bark of the tree has so far received little attention and is usually disposed of as waste. In her doctoral thesis, Charlett Wenig therefore analysed the potential of bark from various tree species in more detail. She is convinced that bark is more than just waste and could be used as a biomaterial in both the construction and textile industries.
Why has tree bark been neglected so far and what makes bark interesting for you?
The structure of tree bark varies greatly - both between different tree species and within a single tree, such as the thick bark of pines compared to their mirroring bark. This diversity makes it difficult to make generalised statements about tree bark. Nevertheless, it makes up around 5-20% of the total volume of a tree and therefore represents a considerable, as yet underutilised resource. For me, the potential lies in making tree bark usable in a high-quality, long-term and sustainable way in order to develop it into a valuable material for various areas of application.
In your dissertation, you analysed the properties of the bark of various trees. What findings did you come to?
Each tree bark has specific properties that can be utilised in a targeted manner. Pine bark, for example, can be made more flexible by treating it with a water-glycerine solution. The resulting material is reminiscent of a mixture of leather and wood in terms of its feel and flexibility. These properties open up a wide range of possible applications, for example in the manufacture of accessories or for temporary textile structures in architecture.
What have your tests revealed regarding the processing of the bark? Which products and applications does it specifically affect?
The test results for processing tree bark show that the results vary greatly depending on the type of bark. Panel materials could be pressed from oak, larch, pine and birch that do not require the addition of adhesives and could potentially be used in the furniture industry. Bark panels could be used in interior design, for example as floor coverings. Their natural aesthetics and stability open up a wide range of possibilities for sustainable applications. Flexibilised bark also shows potential, for example for decorative or temporary surfaces in building and interior design. In addition to bark panels and flexibilised bark, porcelain glazes have also been produced from the ash that remains after the bark is burned. The chemical composition of the respective type of bark influences the colour of the glaze and opens up further application possibilities, for example in the field of ceramic design.
In which areas could bark replace traditional raw materials such as wood as a biomaterial in the future?
Bark should not primarily be seen as a substitute for wood, but should rather be used in applications that correspond to its specific material properties. High-quality applications in which the bark is only minimally modified are particularly desirable. This favours long-term cascading use and enables sustainable value creation from this local biomaterial.
Interview: Beatrix Boldt
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