Decay of a Roman age pine wood studied by micro magnetic resonance imaging, diffusion nuclear magnetic resonance and portable nuclear magnetic resonance

Wood is a hygroscopic biodegradable porous material widely used by men in the past to create artworks. Its total preservation over time is quite rare and one of the best preservation modalities is waterlogging. Observing the anatomy of waterlogged archaeological wood could also be complicated because of its bacterial degradation. However, the characterization of wood morphology and conservation state is a fundamental step before starting any restoration intervention as it allows to extract information about past climatic conditions and human activities. In this work, a micro-invasive approach based on the combined use of high-resolution magnetic resonance imaging (MRI) and diffusion-nuclear magnetic resonance (NMR) was tested both on a modern and an ancient pine wood sample. Furthermore, a completely non-invasive analysis was performed by using portable NMR. This multi-analytical NMR approach allowed to highlight the effect of decay on the wood microstructure, through alterations in the pores size, tortuosity, and images contrast of the ancient pine compared to the modern one. This work pointed out the different but complementary multi-parametric information that can be obtained by using NMR and tested the potential of high-field MRI and low-field portable NMR in the detection of wood diagnostic features.