European co-operation in wood research from native wood to engineered materials. Part 1: Chemical modification with native impregnation agents

The paper presents the results of a German – Czech – Hungarian – Slovenian wood research consortium, dealing with wood modification techniques by using renewable modification agents for the outdoor use of local, originally non-durable modified wood species like beech, poplar and pine sapwood. Higher value assortments of naturally durable and dimensional stable wood species, like oak and black locust from European forests, or others from tropical/sub-tropical forests are limited and partly criticized due to their non-sustainable production and harvesting conditions. Other reasons are the usage of non-local wood sources or the biocide treatment of non-durable species which have a higher impact on the environment because of long distance transport and the use of environmental critical chemicals. Due to simultaneously limited raw material volumes from fossil origin and their negative impact on climate and environment, the production and application of sustainable and renewable materials, like wood or further biomass assortments, become more and more important. Not only the sustainable production and use of the CO2-fixing material WOOD itself, but also the production and utilization of renewable liquid agents for the impregnation stage in the wood modification process-chain as well as the finishing or gluing process-steps are additionally helpful to improve the sustainability of the industrial production. The results show, that extracts from plant or tree residues with natural biocide or cross-linking behaviour as well as heat-treatment process residues of biomass materials, like collected liquids from thermal modification processes or hydro-thermal carbonised as well as pyrolysed or liquefied biomass or wood residues can result in a distinct improvement on the wood properties. These enhanced wood qualities enable the outdoor use of originally non-durable or non-dimensionally stable wood assortments.