Dendrochronological assessment of chestnut (Castanea sativa Mill.) for dating purposes in Central Italy

Chestnut is the most common species used for building construction in Central Italy, but the built chronologies are still floating. This is due to a lack of long master chronologies built for chestnut in these regions and because of the lack of agreement with the very few up to date chestnut curves published for other areas. Chestnut appears to be a suitable species for performing dendrochronological analysis because it forms annual rings, and is a ring-porous species. Nevertheless it shows a very fast growth rate, which results in the presence of only a low number of annual rings even in large beams. To further the understanding of the dendrochronological characteristics that are important for dating purposes, this paper discusses an investigation based an a dendrochronological assessment of living chestnut trees.

In total 89 trees from five stands were sampled in Central Italy. The analysis was performed by testing the quality of single master chronologies and comparing the dendrochronological behaviour of trees of the same stand, the crossdating of chestnut chronologies of different provenances, and the interspecific synchronization with oak, beech and silver fir. These trees are the most widespread species in Central Italy and for which reference chronologies have been recently developed - useful for dating purposes. Chestnut chronologies show rather mean sensitivity values. The mean values of synchronization, according to the mean Gleichläufigkeit (GLK) value, mean correlation value (RBT) and expressed population signal (EPS), among the single curves of the same site are not high. Nevertheless, the number of pointer intervals calculated in the site chronologies can be considered rather high in some periods, and the coincidence of maximum and minimum ring width allows the individual curves to be fitted into the mean site chronology. The results of intraspecific synchronization among chestnut site chronologies are not encouraging. Nevertheless, the degree of visual matching among the chronologies play an important role. The best interspecific synchronization was obtained with oak. No notable correlation was found with beech and silver fir.