stable isotopes; plant physiology; dendroecology; tree ring; transpiration; soil moisture; photosynthesis; Swiss Alps; larix decidua; picea abies; Carbon isotopes; climate change; larch; mechanistic model; oxygen isotopes; spruce; stomatal conductance; temperature
Treydte Kerstin, Boda Sonja, Graf Pannatier Elisabeth, Fonti Patrick, Frank David, Ullrich Bastian, Saurer Matthias, Siegwolf Rolf, Battipaglia Giovanna, Werner Willy, Gessler Arthur (2014), Seasonal transfer of oxygen isotopes from precipitation and soil to the tree ring: Source water versus needle water enrichment, in New Phytologist
, 202, 772-783.
Simard Sonia, Giovannelli Alessio, Treydte Kerstin, Traversi Maria Laura, King Gregory, Frank David, Fonti Patrick (2013), Intra-annual dynamics of non-structural carbohydrates in the cambium of mature conifer trees reflects radial growth demands, in Tree Physioloy
, 33, 913-923.
Ullrich Bastian, Graf Pannatier Elisabeth, Saurer Matthias, Simard Sonia, Treydte Kerstin (2013), Stable oxygen isotopes in xylem water and soil water of alpine trees, in Tree Rings in Archeology, Climatology and Ecology
, Potsdam 11, 11.
Gessler Arthur, Brandes Elke, Keitel Claudia, Boda Sonja, Kayler Zachary, Granier Andre, Barbour Margaret, Farquhar Graham, Treydte Kerstin (2013), The oxygen isotope enrichment of leaf-exported assimilates - does it always reflect lamina leaf water enrichment?, in New Phytologist
, 200(1), 144-157.
Treydte Kerstin, Sauerstoff-Isotope in der Paläoklimatologie, in Geografische Rundschau
Gessler Arthur, Ferrio Juan Pedrio, Hommel Robert, Treydte Kerstin, Werner Roland, Monson Russell, Stable isotopes in tree rings: towards a mechanistic understanding of isotope fractionation and mixing processes from the leaves to the wood, in Tree Physiology
Temperatures in Switzerland increased about 0.57°C over the last three decades (Rebetez & Reinhard 2007) and even though considerable uncertainty exists in future projections, General Circulation Models predict that this increase will continue during the 21st century and beyond (IPCC 2007; Stott et al. 2006). Accompanied by changes in the water supply due to the expected increase in the frequency and intensity of heavy precipitation and/or drought events, these effects will strongly force changes in forest productivity, spatial distribution of tree species, and changes in the species composition within forests. Projections of the future dimensions and interactions of these effects require detailed understanding of short and long-term changes in eco-physiological responses to past and present climate variation. Stable isotopes in tree rings have become a significant tool in obtaining retrospective insight into the plant physiological response to climate and other environmental variables. The increasing number of isotope records, however, also highlights important unsolved questions and current limitations of this tree-ring parameter. Obviously, an improved understanding of the mechanisms leading to variations in the tree’s internal carbon and water cycle in relation to climate, soil moisture conditions, transpiration and expansion of the root system is urgently needed. Moreover, disentangling the physiological processes and meteorological variables associated is a prerequisite for an accurate interpretation of d13C and d18O in tree-ring ecology. ISOPATH aims to decipher the origin and variability of the isotopic signal in the tree rings of two alpine species, frequently used in climate reconstructions, and to understand the environmental and physiological information encoded. We will develop weekly resolved records of d18O and d13C in xylem and needle water, needle sugars, phloem sugars and stem wood/cellulose of two physiologically differing species (Larix decidua and Picea abies) growing under varying temperature, soil moisture and relative humidity conditions. Those data will be related to a large suite of external variables including precipitation and soil water d18?, temperature, and vapour pressure deficit, partly measured in another SNF-project at the same sites (INTEGRAL). We systematically act (i) on a spatial scale by following the complete pathway of stable isotopes from the atmosphere into the tree ring under varying environmental conditions and (ii) on a temporal scale by studying seasonal cycles of the isotope signals in all these different components, covering four growth seasons (2008-2011). This unique dataset in terms of length, resolution and number of measured variables will be used to test and improve advanced models for isotope fractionation at the leaf level and in the tree ring, in relation to species-specific traits, temperature and soil moisture conditions. The measured and modelled isotope signatures will allow to predict plant physiological adaptation in the alpine environment to climate change of the 21st century.