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The current trend for sustainable utilisation of limited resources is stimulating the scientific research for previously neglected raw materials that could also be used for new value added products. Bark, which is a natural insulation material of trees, could be used as technical insulation material. This paper focuses on the effects of particle orientation in light larch (Larix decidua) bark insulation boards on their physical-mechanical and thermal properties. The experimental design is based on the variation of the particle orientation (orthogonal or parallel to the panel plane) and the board density (200-500 kg/ m 3 ). The mechanical properties, water absorption, thickness swelling and thermal conductivity of the boards were tested. The results showed a significant influence of the particle orientation and the density on the measured properties of the bark panels. This implies that the bark particle orientation is an important factor when producing insulation panels with specific characteristics. Suggestions for efficient use of bark particleboard are given.

Tree bark is an interesting source for various building and furniture materials. It holds a high number of volatile components—resulting in emissions whose effects on building residents have to be considered. Spruce and larch barks were dried using different methods and prepared as loose particles and panels. The VOC (volatile organic compound) emissions after 3 and 14 days were measured in a small chamber using gas chromatography and coupled mass spectroscopy. The influence of bark type, drying method, hot pressing and time on the emissions was quantified. The total volatile organic compounds (TVOC) emissions from spruce bark were higher than those from larch bark. High-temperature treatment and time significantly decrease TVOC emissions from the investigated barks. Terpenes, aldehydes and acids were analysed in the emitting gases. The high temperatures whilst pressing panels are problematic due to furfural constitution. Its emissions and partly those of 2-octenal and acetic acid are relevant for present and upcoming evaluation schemes. Aldehydes are the critical substance when using bark in the interior and must be controlled in product development.