Mauro Bernabei

The Baptistry of Saint John in Florence: The Scientific Dating of the Timber Structure of the Dome

ABSTRACT The construction of the Baptistry of Saint John has a debated and uncertain history; the hypothesis on its main construction phases may span from the Roman period to the 13th century, according to different authors. This uncertainty is mainly due to the lack of primary sources and certain dating issues. By combining dendrochronological analysis and radiocarbon dating, some light was shed on the building’s history. Open at least from 897, in 1059 Pope Nicholas II re-consecrated the baptistry after several renovations. Around that period, the octagonal dome was probably built by using chestnut beams to tie the structure together. The dendrochronological analysis dated the silver fir element to 1268. This element possibly represents a replacement coincident with the period, between 1270 and 1300, when a substantial part of the mosaics of the dome was positioned.

Distinguishing root- and stem-wood of Picea Abies

In archaeology, palaeobotany and dendrochronology, it can be important to distinguish between root- and stem-wood. Although numerous studies have described the root-wood of various species in great detail, there is, as yet, no quick and generally accepted wood anatomy-based method to distinguish Norway spruce root- from stem-wood. This study compared the anatomical characteristics of Norway spruce root- and stem-wood, and found it was possible to distinguish these two parts of the tree by differences in the average number of rows of ray tracheids as viewed in radial section, and in the frequency of rays per mm2 as viewed in tangential section. The reliability of these criteria was verified in a double-blind trial. Finally, a cross-comparison between Norway spruce and European larch root- and stem-wood characteristics was carried out, and it was determined that spruce root-wood can be distinguished from larch stem- or root-wood.

Observations on Holocene subfossil tree remains from high-elevation sites in the Italian Alps:

Subfossil tree remains from 38 high-elevation sites in the eastern Alps, which were mostly located in the province of Trentino, Italy, were dendrochronologically analysed. A total of 909 samples were collected, 497 of which were dated to calendar years through dendrochronology and separated into six groups. A further tree-ring series of 20 samples were cross-dated into two groups and their ages established by means of radiocarbon dating. The new Trentino Chronology that was established on the basis of these samples covers more than 80% of the last ca. 11,500 years. The uneven distribution of wood samples through time is most likely caused by different factors, for example, climatic and anthropogenic factors. According to our observations, the trees fell at the sites where they were found. The tree-ring series show that trees often died after a period of pronounced growth decline, for example, as a consequence of variations in groundwater levels. A comparison of the Holocene sample distribution of the new Trentino Chronology with contemporaneous records of other European tree-ring chronologies suggests that, at least partly, the greater scale of climatic variability influenced the depositional frequency. The new data contribute to our understanding of past climatic variability and environmental dynamics.

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

ABSTRACT 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 unfavorable environmental conditions of the attic, which can be attributed to the infiltration of moisture from the top of the roof.

Inside the Dogon Masks: The Selection of Woods for Ritual Objects

At the foot of the Bandiagara cliffs in Mali lives one of the most studied and yet most mysterious ethnic groups of West Africa, the Dogon. According to their religion, masks have a key role in traditional rites, since they are the link between the earthly and the divine. The production and maintenance of such important tools have precise rules handed down by the Dogon secret society called Awa. Fifteen traditional Dogon masks were studied to ascertain the wood species selected to carve them. The analysis shows the occasional use of marula (Sclerocarya birrea, 3 masks) and African grape (Lannea spec., 2 masks) and a preference for ceiba (Ceiba pentandra, 10 masks), a tree revered as sacred by the Dogon. The results suggest potential implications concerning the use of trees and woods in Dogon tradition.

Middle Eocene (Bartonian) Ficus from Monte di Malo (Vicenza - Italy)

The Middle Eocene (Bartonian, ~ 40 Ma) deposits of the Lessini Mountains in the Veneta region are well-known for their well-preserved fossil plants which have been studied since the XVII century. A fossil wood sample recently found in the Val Matta area, in the Municipality of Monte di Malo (Vicenza, Italy), is described. This piece of wood has anatomical characteristics that occur in the extant genus Ficus of the Moraceae, and it is Europe’s oldest known wood of the genus.

The woods of the wooden agricultural sledges in Trentino Region

Dieci tregge, 10 slitte simbolo delle utilizzazioni forestali e montane della tradizione sono state indagate nei loro componenti strutturali. Per ogni elemento e stato raccolto un campione destinato al riconoscimento di specie secondo quanto previsto dalla norma UNI 11118:2004. I risultati dell’identificazione sono stati confrontati con la tradizione popolare e valutati dal punto di vista della tecnologia del legno. I manufatti indagati manifestano un impiego diversificato delle varie specie legnose, generalmente coerente con quanto segnalato dalla tradizione, da considerare corretto alla luce delle esigenze meccaniche a carico dei diversi comparti strutturali. Il lavoro vuole essere un contributo per la valorizzazione della cultura e tradizione popolare fornendo elementi conoscitivi su cui impostare futuri interventi di manutenzione e restauro.