Two well preserved stems of fossil sequoiadendron giganteum excavated in Turkey were studied using electron microscopic and chemical methods. Chemical analysis included determination of main constituents (lignin, cellulose, polyoses) as well as detailed analysis of extractives recovered with different solvents and applying e.g. FTIR, GC, GC-MS techniques. Special attention was paid to the determination of free and ester-bonded acidic groups. The results suggest that the in situ autohydrolysis could have been the major mechanism of degradation which, however, did not reach a very advanced state. The overall look at all the results, particularly at the ultramicroscopic pictures, leads to the assumption that this sample might be not as old as suggested by the common conclusions based on the beginning of the glacial period (> 10(6) a). There could have been small ecological niches near the Mediterranean sea where sequoia species were able to survive several glacial and interglacial periods. Two independent determinations in Italy and Germany using the C-14-method limited the age at 41,000 years or higher.