Aging and fossilization of wood and its components |
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| Authors: | Prof Dr Dietrich Fengel |
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| Institution: | (1) Institut für Holzforschung der Universität München, Winzererstr. 45, 40 München, Germany |
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| Abstract: | Summary Aging of wood begins with the cutting of a tree. The subsequent changes of the wood substance proceed very slowly and depend on environmental conditions. In a hot, dry desert climate wooden objects and cellulose textiles are preserved for several millenia, whereas their degradation is accelerated by conditions which favor the attack of microorganisms.Two conditions under which aging processes take place can be distinguished: a) aerobic conditions as prevailing in wooden buildings, sculptures etc.; b) anaerobic conditions valid for wooden items buried in the ground or submerged in water such as foundation pillars, ships etc. Submersion and underground embedding initiate the very slow process of fossilization in which the cell wall substance is transformed into highly condensed compounds (coalification) or is substituted by minerals (silicification).The various wood components are subjected to different kinds of degradation and conversion. The polysaccharides disappear with aging and seem to be more sensitive than lignin. Although more resistant, the lignin is converted chemically and its structure differs increasingly from its original state. Even extractives may survive millions of years.Academy Lecture presented at the IAWA IUFRO Wood Anatomy Symposium 1990, in Zürich, Switzerland, on 24th July 1990I wish to express my gratitude to members of my staff who have been involved in the study of ancient and fossilized wood as well as of Egyptian linen for the past 23 years: Monika Friedl, Margarete Przyklenk, Manfred Stoll, Ulrike Wegener, Maria Wenzkowski. Many thanks to the guests in my laboratory who worked in this field and whose results were included in this report: Yoon Soo Kim (Kwangju, Korea), Renzo Tomellini (Rome, Italy). And last but not least I am much indebted to several colleagues who provided me with slides or gave permission to reproduce their figures for the Academy Lecture: Takeshi Furuno (Matsue, Shimane, Japan) Dietger Grosser (Munich, FRG), John I. Hedges (Seattle, Wash., USA), Per Hoffmann (Bremerhaven, FRG), John R. Obst (Madison, Wisc., USA). Sylvia Schoske (Munich, FRG) |
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