The influence of climate change on glacier geomorphosites : the case of two Italian glaciers (Miage Glacier, Forni Glacier) investigated through dendrochronology = L’influence du changement climatique sur les géomorphosites glaciaires : le cas de deux glaciers italiens (Glacier du Miage, Glacier des Forni) analysés par dendrochronologie

Global warming is inducing huge changes in Alpine environment: glaciers defined as glacial geomorphosites are affected by severe shrinkage and new territories are progressively becoming suitable for study and evaluation. Landforms related to glacial erosion and deposition are visible at different scales and the consequences of climate change on vegetation (e.g., faster colonisation of new areas) are also evident. Research on the evolution of glacier geomorphosites is significant in order to define their scientific attribute and characteristics as “model of evolution”. This paper presents a proposal to investigate the “natural” evolution of glacier geomorphosites using tree vegetation. The basic concept is that information can be gathered about past and present dynamics by analysing tree-growth on debris-covered glaciers and on their proglacial areas. Moreover, by investigating trees which colonise the glacial forefield of debris-free glaciers, the effects of climate change on tree colonisation can be analysed. New territories deriving from glacial shrinkage are revealed and may be integrated to the glacial geomorphosite defined. The use of dendrochronology for evaluating the evolution of glacial geomorphosites is proposed and discussed on the basis of past studies and of new data collected at two sample sites: the Miage Glacier (western Italian Alps) and the Forni Glacier (central Italian Alps).