Journal Article

Tree height strongly affects estimates of water-use efficiency responses to climate and CO2 using isotopes

4100100411, Heaton, T, Laboratory of Chronology, Finnish Museum of Natural History-Luomus, University of Helsinki, Gloor, E, Luke / Luonnonvarat ja biotuotanto / Ympäristövaikutukset / Ilmastonmuutoksen hillintä ja sopeutuminen, School of Earth and Environment, University of Leeds, Arppe, L, Natural Resources Institute Finland (Luke), 4100300313, Centre for Environmental Geochemistry, University of Nottingham, NERC Isotope Geosciences Facilities, British Geological Survey, Mielikäinen, K, Oinonen, M, Newton, R, Leng, M. J, Luke / Uudet liiketoimintamahdollisuudet / Uudet tuotteet ja teknologiat / Bioraaka-aineet ja tuoteominaisuudet, Clerici, S, Brienen, R. J. W, Bottrell, S, School of Geography, University of Leeds, Helama, Samuli, Boom, A, GFZ - german Research Centre for Geosciences, Section 5.2 Climate Dynamics and Landscape Evolution, School of Geography, University of Leicester, Timonen, Mauri, Callaghan, M, Helle, G

2017

Overview

Various studies report substantial increases in intrinsic water-use efficiency (Wi), estimated using carbon isotopes in tree rings, suggesting trees are gaining increasingly more carbon per unit water lost due to increases in atmospheric CO2. Usually, reconstructions do not, however, correct for the effect of intrinsic developmental changes in Wi as trees grow larger. Here we show, by comparingWi across varying tree sizes at one CO2 level, that ignoring such developmental effects can severely affect inferences of trees’ Wi. Wi doubled or even tripled over a trees’ lifespan in three broadleaf species due to changes in tree height and light availability alone, and there are also weak trends for Pine trees. Developmental trends in broadleaf species are as large as the trends previously assigned to CO2 and climate. Credible future tree ring isotope studies require explicit accounting for species-specific developmental effects before CO2 and climate effects are inferred.

• Publisher: Nature Publishing Group,London,gb,Nature Publishing Group UK,Nature Portfolio
• Subject: 704/158/2466 / 704/47/4113 / Carbon dioxide / Carbon isotopes / Climate / Climate effects / Drought / Humanities and Social Sciences / Isotope studies / Isotopes / multidisciplinary / Pine trees / Science / Science (multidisciplinary) / Tree rings / Trees / Water use