An integrated approach for tracking climate-driven changes in treeline environments on different time scales in the Valle d’Aosta, Italian Alps

Both biotic and abiotic components, characterizing the mountain treeline ecotone, respond differently to climate variations. This study aims at reconstructing climate-driven changes by analyzing soil evolution in late Holocene assessing climatic trends for last centuries years a key high-altitude (2515 m a.s.l.) on SW slope of Becca di Viou (Aosta Valley Region, Italy). approach is based science dendrochronological techniques, together with daily air/soil temperature monitoring four recent growing seasons. Direct measurements show that ongoing temperatures during season, above, are higher than predicted reference values Alpine treeline. Thus, they do not represent limiting factor tree establishment growth, including highest altitudes potential (2625 a.s.l.). Dendrochronological evidences marked sensitivity tree-ring growth early-summer temperatures. During 10-year period 2006–2015, trees around 2300 a.s.l. have grown rate approximately 1.9 times 1810–1819, one coolest periods Little Ice Age. On other hand, soils only an incipient response warming, likely because its resilience regarding changeable environmental conditions different factors influencing development. The rising air temperature, consequent upward shift, could be cause shift from Regosol more Umbric characteristics, but profiles located N facing slopes. Overall, results this integrated permitted quantification responses components through time, emphasizing influence local station responding past change.