Research on wood protection problems in Latvia

The forest sector is an important area in Latvia from all three traditional aspects – economic (contribution to GDP, import-export balance, employment), ecological (“the Lungs of the Earth”, CO2 sequestration, renewable resources) and social (jobs, recreation). In the broadest aspect, a pioneer in wood research, including wood protection in Latvia, was Professor Arvīds Kalniņš (1894–1981). Already in the 1920s–1930s, he became intensely acquainted with forest and wood science, visiting all the leading centres of Europe. Along with forestry, wood as an important forest value, and the possibilities of its use from woodworking to chemical processing became a lifelong task of A. Kalniņš’ research. After the Second World War, in 1946, under the initiative of A. Kalniņš, under the auspices of the Latvian Academy of Sciences (LAS), the Institute of Forestry Problems of the LAS was established. In 1966, it became the leading institute of the field throughout the USSR. Over time, the Institute transformed into the Institute of Wood Chemistry of the LAS (now – Latvian State Institute of Wood Chemistry, LSIWC), standing out in forest research as a separate organisation. This year, the laboratory, along with the Institute, celebrates the 75th anniversary of its existence, like one of the world’s leading wood protection research centres – Forest Products Lab at Mississippi State University. Along with deep practical studies, such as the protection of supports of power transmission lines and sleepers, new wood preservatives and wood impregnation methods were developed, and wood biodegradation processes and mechanisms were studied. In 2020, the laboratory’s research in the field of wood protection was announced by the LAS as one of the most significant achievements in Latvian science of the year. Today, more and more stringent requirements are imposed on wood preservatives, similar to chemical compounds in other areas. At the beginning of this century, a significant breakthrough in the chemical protection of wood took place – the use of the most widely used arsenic and chromium compounds was banned, under the question is the use of creosote. As a matter of urgency, new, so-called second-generation preparations have been developed, which contain basic copper compounds as the dominant biocide, and organic biocides to broaden the spectrum of protective efficacy. During this time, also the Laboratory of Wood Biodegradation and Protection, LSIWC started the study of thermal modification processes and the optimisation of technological parameters for the improvement of biodurability and physical properties of wood of different tree species. In the Laboratory, experimental pilot equipment (WTT, Denmark) was purchased for modification, and a comprehensive study of TM wood and wood composite materials (plywood) was conducted. There has been already relatively a lot of data on coniferous wood TM, so we started a detailed study of deciduous wood – alder, aspen, ash, and birch – TM in order to expand the possibilities of using these species in construction – indoors and outdoors. As a result of the studies, the optimal technological parameters of TM for obtaining deciduous wood with improved and predictable durability characteristics were elucidated.