Activities on hardwood and alternative wood species

The forest conversion over the last decades is an answer to climate change which provokes alterations of the growing conditions. Therefore, the number of mixed stands with more deciduous trees has been highly increased, for instance in Lower Saxony.

As a consequence, coniferous wood lands decrease. This has intensified in recent years because of the drought and the bark beetle calamities. Softwoods like spruce and pine trees have been substituted by hardwoods, mainly beech, in order to develop stable mixed stands in accordance with the habitat. Also, alternative tree species could be used for reforestation.

However, deciduous trees, in particular beech, und coniferous trees like spruce differ in their biological, physical and technological properties. Therefore, increasing significance of deciduous trees provokes research work in the field of hardwood. Since spruce and pine wood are more common in construction, for the cellulose and paper industries or in furniture manufacturing, it is necessary to find ways and means to substitute softwood by hardwood. Therefore, research and development work is necessary for a guaranteed supply of the wood-processing industries.

The initiation, promotion and support of corresponding studies, research projects and development work is a key challenge for the forestry and timber industries. For that reason, the International Association for Technical Issues Related to Wood (iVTH e. V.) together with the Lower Saxony Sustainable Wood Usage Competence Network (NHN e. V.) founded the Hardwood Research Interest Group (IGLHF) in 2011.

The IGLHF was started to promote and support technology oriented scientific studies and projects. Its intention is to initiate and support projects which ascertain the potential and composition of hardwood stocks, marketing possibilities from an economic and commercial viewpoint and new products and processes for using hardwood as a raw material. Projects in the hardwood research field assist in the development of new products in this sector. They will enable both a directed dissemination of results into the practical field and a bundling of knowledge from the practical field for further research. The message here is to strengthen high-quality usage of the renewable and environmentally friendly resource that wood is.

The iVTH continues to initiate and promote research work at the Fraunhofer WKI regarding the use of hardwood, e. g. in layered wood-based materials. Within the scope of the characterization of different hardwoods, the manufacture of rotary cut beech and robinia veneer was examined as well as various aspects of gluing these veneers. The characteristic values of laminated veneer lumber (LVL), made from the beech veneer, were also determined.

The mechanical and hygric properties of local hardwoods and softwoods are well known. This is, however, less true for the emissions of volatile organic compounds (VOCs) from hardwoods and less used softwoods. Studies and research projects in this field have mainly been carried out on softwoods and materials made therefrom. In the case of hardwoods, in contrast, only isolated measurements have been performed to date. Gaps exist primarily in the so-called pioneer wood species, which have hardly been used up to now, if at all. Within a small investigation program of the Fraunhofer WKI and the iVTH, the VOC emissions of the wood species birch and robinia were therefore investigated and compared with available results from beech and oak. Currently, alternative coniferous species such as thuja and various fir species are the focus of the investigations.

Contact:

Prof. Dr. Rainer Marutzky