The Timber Dating of Giotto's Bell Tower in Florence (Italy)

The Bell Tower of the Florence Cathedral is an outstanding example of Italian Gothic architecture and is one of the most famous buildings of Florence. This study aims at characterising the wooden structures of its roof by determining its tree species, dating the structural timber and, thereby, identifying the restoration phases and maintenance operations. Silver fir (Abies alba Mill.) was the only species found, which was floated downstream to Florence from the Casentino area in the Apennines along a network of rivers. Dendrochronological analysis showed that none of the roof timber specimens date back to the 14th century, when the Bell Tower was built. The present structure is therefore the result of repairs and replacements that continually occurred over the last 200 years. As a cause of frequent restoration our analysis indicates fast wood decay under the unfavourable environmental conditions of the attic, which can be attributed to the infiltration of moisture from the top of the roof.