Wood Modification for Under-Utilised Hardwood Species

Abstract

The different wood modification processes give the opportunity to improve the applicability of such wood materials, which due to their lower biological resistance and/or weather resistance and/or dimension stability have a limited application field. Beside several plantation grown species (e.g. poplars or black locust), there are some species that are not plantation grown but available in considerable quantities, but with low added value during their utilization. These species are mainly used for energy recovery, but they have also the potential for the utilization with higher added value (e.g. furniture, claddings, etc.). These hardwood species are Turkey oak (Quercus cerris L.), hornbeam (Carpinus betulus L.) and tree-of-heaven (Ailanthus altissima Mill.). They have in general high density, strength values and surface hardness. By improving of the properties their application could be widened by substituting more valuable wood species. Different modification techniques were used for the improvement of the properties of these wood species, namely heat treatment and oil heat treatment. In this paper selected wood properties were investigated which are important by the specification of the application fields of the treated material.