Comparisons of the Performance of δ¹³C and δ¹⁸O of Fagus sylvatica, Pinus sylvestris, and Quercus petraea in the Record of Past Climate Variations

Abstract

Climate reconstructions in temperate Europe have been widely based on oak species. However, other co‐occurring species, largely distributed in Europe, may be used for recording climate variability. In this paper, we documented the intertrees and interspecies variations over 1960–2007 of oxygen and carbon isotopic compositions in ring cellulose of Fagus sylvatica, Pinus sylvestris, and Quercus petraea co‐occurring in the Fontainebleau forest (France). Our results indicated that large levels of series replication (11 trees on average) were required to generate isotopic mean series representative of the populations. We calculated mean isotopic ratios higher in pine than in the deciduous species and hypothesized that these contrasts resulted from differences in stomatal conductance, phenology, and canopy structure and, for oxygen, also in water uptake depth and isotopic exchange rate. We found that δ18O and δ13C chronologies were significantly correlated to one another in the three species and responded primarily to air moisture and Tmax, which indicated that stomatal conductance was an important driver of changes in both types of records. We determined that the correlations were strong with the May to July climate variables in F. sylvatica and with the July and August ones in Q. petraea and P. sylvestris. We showed that the oxygen records were systematically more coherent than those of carbon. This study demonstrated that δ18O, and to a lesser extent δ13C, from the three different species are reliable proxies for reconstructing past hydroclimatic variations in Europe.

Contrasting patterns of tree species mixture effects on wood δ13C along an environmental gradient

“…Carbon isotope composition in tree rings was systematically higher in pine than in beech (Figure 3), pointing to greater intrinsic water use efficiency for pine compared to beech; this is consistent with previous studies (Daux et al 2018;Hemmings et al 1998;Szczepaneck et al 2006). Several explanations for these differences are possible.…”

Absence of Age‐Related Trends in Stable Oxygen Isotope Ratios From Oak Tree Rings

“…The oxygen isotope ratios in the latewood (summer wood) of UK oak trees and timbers thus record past changes in the amount of May to August rainfall (Young et al, 2015). Oaks in France appear to record a similar signal (Daux et al, 2018;Labuhn et al, 2016).…”

Observed and modelled historical trends in the water‐use efficiency of plants and ecosystems

“…Other sources of uncertainty may affect estimates of WUE, including random and systematic errors for the eddy‐covariance flux measurements (Knauer, Zaehle, et al, ; Richardson et al, ), and analytical error and sampling bias for stable carbon isotopes in tree rings (Daux et al, ; Gessler et al, ). However, these sources of uncertainty do not necessarily have an impact on trends (see Table ).…”