113 WOOD RESEARCH 55 (3): 2010 113-120 COMPARISON OF THE CHEMICAL COMPOSITION OF THE FOSSIL AND RECENT OAK WOOD Krutul Donata, Radomski Andrzej, Zawadzki Janusz, Zielenkiewicz Tomasz, Antczak Andrzej Warsaw University of Life Sciences, Faculty of Wood Technology, Department of Wood Science and Wood Protection Warsaw, Poland ABSTRACT is study was perform to compare the chemical composition of fossil oak wood and recent oak wood. About 2500 years old fossil oak wood and 100 years old recent oak wood were examined. Samples were gained from the outer wood, middle wood and heartwood on the cross section of three stems (both fossil and recent). Contents of extractives, cellulose, 1 % NaOH soluble substances, lignin and ash were analysed. Additionally, concentrations of elements such as Ca, K, Mg, Fe, Mn, Na, Zn and Cu were examined. e results show that there is lower content of cellulose and higher content of lignin in fossil oak wood in relation to recent wood. ere is also much higher amount of calcium and iron, and lower amount of potassium in fossil wood. KEY WORDS: archaeological wood, oak, chemical composition INTRODUCTION Wood undergoes progressive destruction by the action of abiotic and biotic external factors. Wood durability is the time in which wood keeps usable properties. It depends on the wood kind (species) and the environment. Time in the destruction process plays secondary role (Krutul and Kocoń 1982, Dzbeński 1969, 1970, Reinprecht 1992, Dzbeński et al. 1996). High-density wood, which most often corresponds to heartwood, shows higher extractives concentration and is much more durable than sapwood. e living cells are the most susceptible to decomposition. Pectins and hemicelluloses are the components of cell walls, which undergo degradation the most readily (Fengel 1971, 1991). Lignin is much more resistant for destruction as it contains phenolic groups which hinder expansion of majority of microorganisms (Prądzyński and Cichocka 2002). e oak heartwood possesses the highest natural durability among deciduous species of temperate zone. It is confirmed by examples of excavation wood samples of perfect constitution, (2500 years old) from gravel mine in Latoszyn. e aim of this work is the comparison of chemical composition of wood on the cross-section of oak stem received from Latoszyn and recent oak wood (100 years old).