Search

Glacier mass balance reconstructions provide a means of placing relatively short observational records into a longer-term context. Here, we use multiple proxies from Pinus cembra trees from God da Tamangur, combining tree ring anatomy and stable isotope chronologies to reconstruct seasonal glacier mass balance (i.e., winter, summer, and annual mass balance) for the nearby Silvretta Glacier over the last 2 centuries. The combination of tree ring width, radial diameter of earlywood cell lumina, and latewood radial cell wall thickness provides a highly significant reconstruction for summer mass balance, whereas for the winter mass balance, the correlation was less significant but still robust when radial cell lumina were combined with δ18O records. A combination of the reconstructed winter and summer mass balances allows the quantification of the annual mass balance of the Silvretta Glacier for which in situ measurements date back to 1919. Our reconstruction indicates a substantial increase in glacier mass during the first half of the 19th century and an abrupt termination of this phase after the end of the Little Ice Age. Since the 1860s, negative glacier mass balances have been dominant and mass losses accelerate as anthropogenic warming picks up in the Alps. [ABSTRACT FROM AUTHOR]

Glacier mass-balance reconstructions provide a means of placing relatively short observational records into a longer-term context. Here, we use multiple proxies from Pinus cembra trees from God da Tamangur combining tree-ring anatomy and stable isotope chronologies to reconstruct seasonal glacier mass balance (i.e. winter, summer and annual mass balance) for the nearby Silvrettagletscher over the last two centuries. The combination of tree-ring width, radial cell wall thickness and δ13C isotope records provide a highly significant reconstruction for summer mass balance, whereas, for winter mass balance, the correlation was less significant but still robust when radial cell lumen was combined with δ18O and δ13C records. Combination of the reconstructed winter and summer mass balances allows quantification of the annual mass balance of Silvrettagletscher, for which in-situ measurements date back to 1919. Our reconstruction indicates a substantial increase in glacier mass during the first half of the 19th century and an abrupt termination of this phase after the end of the Little Ice Age. Since the 1860s, negative glacier mass balances have been dominant and mass losses accelerate as anthropogenic warming picks up in the Alps. This abrupt termination of the Little Ice Age cannot be found if the mass balance reconstruction is obtained from the gridded temperature and precipitation fields (1 × 1 km) available for Switzerland since 1763. [ABSTRACT FROM AUTHOR]

Glacier mass-balance reconstructions provide a means of placing relatively short observational records into a longerterm context. Here, we use multiple proxies from Pinus cembra trees from God da Tamangur combining tree-ring anatomy and stable isotope chronologies to reconstruct seasonal glacier mass balance (i.e. winter, summer and annual mass balance) for the nearby Silvrettagletscher over the last two centuries. The combination of tree-ring width, radial cell wall thickness and δ13C isotope records provide a highly significant reconstruction for summer mass balance, whereas, for winter mass balance, 25 the correlation was less significant but still robust when radial cell lumen was combined with δ18O and δ13C records. Combination of the reconstructed winter and summer mass balances allows quantification of the annual mass balance of Silvrettagletscher, for which in-situ measurements date back to 1919. Our reconstruction indicates a substantial increase in glacier mass during the first half of the 19th century and an abrupt termination of this phase after the end of the Little Ice Age. Since the 1860s, negative glacier mass balances have been dominant and mass losses accelerate as anthropogenic warming 30 picks up in the Alps. This abrupt termination of the Little Ice Age cannot be found if the mass balance reconstruction is obtained from the gridded temperature and precipitation fields (1 1 km) available for Switzerland since 1763. [ABSTRACT FROM AUTHOR]

The medium-high mountain ranges of Western Europe are undergoing rapid socio-environmental changes. The aim of this study is to show that their landscape can be strongly shaped by the actions of avalanche activity, humans and climate. The study area is the Rothenbachkopf-Rainkopf complex, a site representative of avalanche-prone areas of the Vosges Mountains (France). A geo-historical approach documents regular avalanche activity over more than 200 years on 13 paths. A diachronic analysis of historical maps and photographs demonstrates substantial afforestation (from 60 to 80% of the total surface since 1832). LIDAR data and field surveys highlight the existence of a longitudinal and transversal structure of trees. Hence, the avalanche, human and climate activity footprints are retained by the landscape, which rapidly adapts to these changing drivers. Specifically, the pattern of tree species and heights results from a near equilibrium with regular avalanche activity sometimes disturbed by major avalanches that induce quasi-cyclic changes in the landscape mosaic. The afforestation trend is attributable to profound changes in silvo-pastoral practices, supplemented by the impact of climate change. The wider relevance of the results in relation to the local context is discussed, as well as outlooks that can refine our understanding of this complex system. [ABSTRACT FROM AUTHOR]

Sea cliffs represent 80% of the world's coasts and can be found virtually in all types of morphogenetic environments. Most studies on rocky environments focused on the impacts of modern sea level rise on cliff stability derived from sequential surveys, direct measurements or erosional features in anthropogenic structures. In this study, we explore the potential of dendrogeomorphic techniques to quantify multidecadal changes in coastal environments on Porquerolles Island (France). We sampled a total of 56 cross‐sections from 16 Pinus halepensis Mill. roots growing on former alluvial deposits and on sandy‐gravelly cliffs to quantify mean annual cliff retreat rates as well as changes in cliff geometry. Anatomical changes in roots have been used successfully in the past to quantify continuous denudation rates on slopes, channel incision and gullying processes but the approach has not been used so far in a coastal cliff context. At Porquerolles Island, reconstructed rates of cliff retreat cover 30–40 years and show average erosion rates between 0.6 and 3.9 cm yr−1 (average: 2.1 cm yr−1). Highest rates are observed at Pointe de la Tufière (2.6–3.9 cm yr−1), a small rock promontory that is more exposed to wave and storm surges than the remainder of the study area. By contrast, lower erosion rates are recorded at cliffs protected by the La Courtade pocket beach (0.6–1.9 cm yr−1). This contribution demonstrates that dendrogeomorphic analyses of roots clearly have a significant potential and that they are a powerful tool for the quantification of multidecadal rates of cliff retreat in areas where measurements of past erosion are lacking. More specifically, the approach also has clear advantages over the shorter time series obtained with repeat monitoring (e.g. terrestrial laser scanning, sensors, erosion pins) or over longer, but more coarsely resolved records obtained from aerial photographs or radio‐nuclides. © 2018 John Wiley & Sons, Ltd. Determination of exposure years was based on the sharp decrease of cell lumen area of earlywood tracheids. This contribution demonstrates that dendrogeomorphic analyses of roots clearly have a significant potential and that they are a powerful tool for the quantification of multidecadal rates of cliff retreat in areas where measurements of past erosion are lacking. [ABSTRACT FROM AUTHOR]