Chemical Characterisation of Wood of Roman Ships Brought to Light in the Recently Discovered Ancient Harbour of Pisa (Tuscany, Italy)

Chemical analyses of wood samples from two ships of the ancient harbour of Pisa have shown that they are drastically degraded by the environment where they have lain. Holocellulose contents are reduced to very low values (between 4.9 and 27.3%) in comparison with reference species (55.9–68.1%). Accordingly, the lignin contents are enhanced, following the trend shown by aged wood in moist environments. The effect of time on the ships is evident since the older one, ship L, is more degraded than the younger one, ship C.The dehydroabietic acid found in ancient oak samples is evidence of the ancient caulking of hull. The high degradation of Pisa woods is also shown by basal density values ranging between 0.13 and 0.23.