0000000001311660
AUTHOR
Matthias Saurer
Spatio‐temporal patterns of tree growth as related to carbon isotope fractionation in European forests under changing climate
Aim The aim was to decipher Europe‐wide spatio‐temporal patterns of forest growth dynamics and their associations with carbon isotope fractionation processes inferred from tree rings as modulated by climate warming. Location Europe and North Africa (30‒70° N, 10° W‒35° E). Time period 1901‒2003. Major taxa studied Temperate and Euro‐Siberian trees. Methods We characterize changes in the relationship between tree growth and carbon isotope fractionation over the 20th century using a European network consisting of 20 site chronologies. Using indexed tree‐ring widths (TRWi), we assess shifts in the temporal coherence of radial growth across sites (synchrony) for five forest ecosystems (Atlantic…
Water-use efficiency and transpiration across European forests during the Anthropocene
Considering the combined effects of CO2 fertilization and climate change drivers on plant physiology leads to a modest increase in simulated European forest transpiration in spite of the effects of CO2-induced stomatal closure. The Earth’s carbon and hydrologic cycles are intimately coupled by gas exchange through plant stomata1,2,3. However, uncertainties in the magnitude4,5,6 and consequences7,8 of the physiological responses9,10 of plants to elevated CO2 in natural environments hinders modelling of terrestrial water cycling and carbon storage11. Here we use annually resolved long-term δ13C tree-ring measurements across a European forest network to reconstruct the physiologically driven r…
A 350 year drought reconstruction from Alpine tree ring stable isotopes
[1] Climate reconstructions based on stable isotopes in tree rings rely on the assumption that fractionation-controlling processes are strongly linked to meteorological variables. In this context, we investigated the climate sensitivity of 350 years of carbon and oxygen isotope ratios of tree ring cellulose from European larch obtained at a high-elevation site in the Swiss Alps (∼2100 m above sea level). Unlike tree ring width and maximum latewood density, which contain only summer temperature information at this site, we found that our stable isotope series reveal additionally to temperature a striking sensitivity to precipitation (mainly for carbon) and sunshine duration (mainly for oxyge…
Long-term summer temperature variations in the Pyrenees from detrended stable carbon isotopes
Abstract Substantial effort has recently been put into the development of climate reconstructions from tree-ring stable carbon isotopes, though the interpretation of long-term trends retained in such timeseries remains challenging. Here we use detrended δ13C measurements in Pinus uncinata tree-rings, from the Spanish Pyrenees, to reconstruct decadal variations in summer temperature back to the 13th century. The June-August temperature signal of this reconstruction is attributed using decadally as well as annually resolved, 20th century δ13C data. Results indicate that late 20th century warming has not been unique within the context of the past 750 years. Our reconstruction contains greater …
Low-frequency noise inδ13C andδ18O tree ring data: A case study ofPinus uncinatain the Spanish Pyrenees
[1] Isotopic discrimination measurements in tree rings are becoming increasingly important estimators of past environmental change. Potential biases inherent to these parameters, including age trend and level offset are, however, not well understood. We here perform measurements on a new millennium-long data set of decadally resolved δ18O and δ13C discrimination from 25 high-elevation pine trees in the Spanish Pyrenees to investigate whether such low-frequency biases exist and how they alter the long-term behavior of derived time series. Alignment of the tree ring data by biological age reveals age trends over the first one to four centuries after germination. On average, isotope values cha…
Climate Sensitivity and Parameter Coherency in Annually Resolved δ13C and δ18O from Pinus uncinata Tree-Ring Data in the Spanish Pyrenees
We explore the 20th century climate sensitivity of annually resolved carbon and oxygen isotope ratios in five Pinus uncinata individuals from the upper treeline in similar to 2400 m asl of the Span ...
Stable carbon isotope ratios of tree-ring cellulose from the site network of the EU-Project ‘ISONET’
The ISONET project has been striving to improve greatly our understanding of European climate systems providing independent quantitative data for model verification and policy making. A network of 24 sites provides dendrochronological coverage from Iberia to Fennoscandia, Caledonia and the Tyrol. The stable isotope (C, H, O) ratios of these annually resolved time series shall be analysed within this project, to reconstruct past climate regimes (temperature, relative humidity and precipitation characteristics) for the last 400 years. Climate variability shall be addressed on three timescales; decade-century (source water/air mass dominance); inter-annual (quantifying baseline variability, ex…
Stable oxygen isotope ratios of tree-ring cellulose from the site network of the EU-Project ‘ISONET’
24 European annually resolved stable isotope chronologies have been constructed from tree ring cellulose for the last 400 years (1600CE – 2003CE) for carbon and oxygen and for the last 100 years for hydrogen. Data was produced within the ISONET project (400 Years of Annual Reconstructions of European Climate Variability Using a Highly Resolved Isotopic Network,) to initiate an extensive spatiotemporal tree-ring stable isotope network across Europe funded as part of the fifth EC Framework Programme “Energy, Environment and Sustainable Development”. This data set comprises the ISONET δ18O records.