In service, wood foundation poles are subjected to water level fluctuation in soil. While wood is saturated by water only bacterial decay occurs. When oxygen content increases and moisture content decreases, severe fungal attack may occur. To evaluate the long term fungal durability of wood foundation pole in the context of service, 300 years waterlogged archaeological wood poles were used. The oak wood was characterized and subjected to fungal degradation in controlled conditions. Upper part of the pole was only subjected to water. It was analysed separately of the buried part. Before fungal attack, mechanical resistance of wood was similar to current oak. Global chemical composition showed only small alterations in wood polymer contents. Extractive and ashes amounts exhibited the highest differences when compared to current oak. Transmitted infrared spectroscopy showed that cell wall carbohydrates content was decreased at low level in archaeological samples compare to current heartwood. The ashes composition analysis of archaeological wood samples revealed unusual high level of iron and calcium. Scanning electron microscopy with microanalysis analysis showed that wood anatomy was altered. Minerals were homogeneously localized in wood structures. When subjected to fungal degradation, archaeological woods were more degraded by white and brown rots than current oak heartwood samples. Role of iron in oxalate mediated Fenton degradation mechanism was investigated. In archaeological wood samples degraded by Poria placenta and Coniophora puteana high number of crystal structures surrounding hyphae were observed and identified as calcium oxalate. The possible inhibitory role of high iron content on Trametes versicolor wood degradation is also discussed. Finally, this work point the role of metal cations adsorbed in wood during the fungal degradation of the material.

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