Pinus cembra L. tree-ring data as a proxy for summer glacial mass balance variability in the Rhaetian Alps

Glacial extent and mass balance are sensitive climate proxies providing solid information on pastclimatic conditions. However, series of annual mass-balance measurements of more than 60 yearsare scarce. To our knowledge, this is the first time the latewood density data (MXD) of the Swissstone pine (Pinus cembra L.) have been used to reconstruct the summer mass balance (B s ) of anAlpine glacier. The MXD-based B s well correlates with a B s reconstruction based on the May toSeptember temperature. Winter precipitation has been used as an independent proxy to infer thewinter mass balance and to obtain an annual mass-balance (B n ) estimate dating back to the gla-ciological year 1811/12. The reconstructed MXD/precipitation-based B n well correlates with thedata both of the Careser and of other Alpine glaciers measured by the glaciological method. Anumber of critical issues should be considered in both proxies, including non-linear responseof glacial mass balance to temperature, bedrock topography, ice thinning and fragmentation,MXD acquisition and standardization methods, and finally the 'divergence problem' responsiblefor the recently reduced sensitivity of the dendrochronological data. Nevertheless, our resultshighlight the possibility of performing MXD-based dendroglaciological reconstructions usingthis stable and reliable proxy.