Ranking of tree-ring based hydroclimate reconstructions of the past millennium

PIERMATTEI, ALMA; BÜNTGEN, ULF; LUTERBACHER, JÜRG; STAHLE, DAVID W.; ESPER, JAN; SEIM, ANDREA; HE, MINHUI; SCHNEIDER, LEA; VILLALBA, RICARDO; LJUNGQVIST, FREDRIK CHARPENTIER; KRUSIC, PAUL J.; KIRDYANOV, ALEXANDER V.; SEFTIGEN, KRISTINA; YANG, BAO

QUATERNARY SCIENCE REVIEWS

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2020 vol. 230

0277-3791

To place recent hydroclimate changes, including drought occurrences, in a long-term historical context,tree-ring records serve as an important natural archive. Here, we evaluate 46 millennium-long tree-ringbased hydroclimate reconstructions for their Data Homogeneity, Sample Replication, Growth Coherence,Chronology Development, and Climate Signal based on criteria published by Esper et al. (2016) to assess treeringbased temperature reconstructions. The compilation of 46 individually calibrated site reconstructionsincludes 37 different tree species and stem from North America (n ¼ 29), Asia (n ¼ 10); Europe (n ¼ 5),northern Africa (n ¼ 1) and southern South America (n ¼ 1). For each criterion, the individual reconstructionswere ranked in four groups, and results showed that no reconstruction scores highest orlowest for all analyzed parameters. We find no geographical differences in the overall ranking, but reconstructionsfrom arid and semi-arid environments tend to score highest. A strong and stable hydroclimatesignal is found to be of greater importance than a long calibration period. The most challengingtrade-off identified is between high continuous sample replications, as well as a well-mixed age classdistribution over time, and a good internal growth coherence. Unlike temperature reconstructions, a highproportion of the hydroclimate reconstructions are produced using individual series detrending methodsremoving centennial-scale variability. By providing a quantitative and objective evaluation of all availabletree-ring based hydroclimate reconstructions we hope to boost future improvements in the developmentof such records and provide practical guidance to secondary users of these reconstructions.