Climate signals in a multispecies tree-ring network from central and southern Italy and reconstruction of the late summer temperatures since the early 1700s

• Published in: Climate of the past 2017-11, Vol.13 (11), p.1451-1471
• Main Authors: Leonelli, Giovanni, Coppola, Anna, Salvatore, Maria Cristina, Baroni, Carlo, Battipaglia, Giovanna, Gentilesca, Tiziana, Ripullone, Francesco, Borghetti, Marco, Conte, Emanuele, Tognetti, Roberto, Marchetti, Marco, Lombardi, Fabio, Brunetti, Michele, Maugeri, Maurizio, Pelfini, Manuela, Cherubini, Paolo, Provenzale, Antonello, Maggi, Valter
• Format: Article
• Language: English
• Subjects: 20th century; Annual variations; Archives & records; Chronology; Climate; Climate change; Coniferous trees; Conifers; Correlation analysis; Divergence; Drought; Drought conditions; Ecosystems; Environmental aspects; Growing season; Latitudinal variations; Measurement; Precipitation; Precipitation and drought; Precipitation patterns; Rainfall; Reconstruction; Seasonal variations; Standardized precipitation index; Summer; Summer precipitation; Summer temperatures; Temperature; Temperature effects; Temperature variability; Tree rings; Trees; Variability
• ISSN: 1814-9332; 1814-9324; 1814-9332
• DOI: 10.5194/cp-13-1451-2017

A first assessment of the main climatic drivers that modulate the tree-ring width (RW) and maximum latewood density (MXD) along the Italian Peninsula and northeastern Sicily was performed using 27 forest sites, which include conifers (RW and MXD) and broadleaves (only RW). Tree-ring data were compared using the correlation analysis of the monthly and seasonal variables of temperature, precipitation and standardized precipitation index (SPI, used to characterize meteorological droughts) against each species-specific site chronology and against the highly sensitive to climate (HSTC) chronologies (based on selected indexed individual series). We find that climate signals in conifer MXD are stronger and more stable over time than those in conifer and broadleaf RW. In particular, conifer MXD variability is directly influenced by the late summer (August, September) temperature and is inversely influenced by the summer precipitation and droughts (SPI at a timescale of 3 months). The MXD sensitivity to August–September (AS) temperature and to summer drought is mainly driven by the latitudinal gradient of summer precipitation amounts, with sites in the northern Apennines showing stronger climate signals than sites in the south. Conifer RW is influenced by the temperature and drought of the previous summer, whereas broadleaf RW is more influenced by summer precipitation and drought of the current growing season. The reconstruction of the late summer temperatures for the Italian Peninsula for the past 300 years, based on the HSTC chronology of conifer MXD, shows a stable model performance that underlines periods of climatic cooling (and likely also wetter conditions) in 1699, 1740, 1814, 1914 and 1938, and follows well the variability of the instrumental record and of other tree-ring-based reconstructions in the region. Considering a 20-year low-pass-filtered series, the reconstructed temperature record consistently deviates