Age-Effect on Intra-Annual δ13C-Variability within Scots Pine Tree-Rings from Central Siberia

Abstract

Intra-annual tree-ring parameters are increasingly used in dendroecology thanks to their high temporal resolution. To better understand the nature of intra-ring proxy signals, we compared old and young trees according to the different ways in which they respond to climate. The study was carried out in central Siberia (Russia, 60 • 75 N, 89 • 38 E) in two even-aged Pinus sylvestris L. stands of different ages (20 and 220 years). Ring width, cell size, and intra-annual δ 13 C were measured for 4 to 27 tree rings, depending on age group (young vs. old) and tree-ring parameter. Wood formation was monitored to link tree-ring position to its time of formation. Results indicated more distinct intra-annual δ 13 C patterns at both the beginning and end of the ring of young trees compared to old ones. Older trees showed a stronger significant correlation between δ 13 C across the ring border, indicating a stronger carry-over effect of the previous year's growing conditions on current year wood production. This suggests that tree age/size influences the magnitude of the transfer of mobile carbon reserves across the years.

Age‐Related Climate Response of Tree‐Ring δ13C and δ18O From Spruce in Northwestern China, With Implications for Relative Humidity Reconstructions

“…The strong autocorrelations we found in tree‐ring δ 13 C and the response to climate in the previous year support this hypothesis (Figures 4 and 5). Similarly, 0.3–0.9‰ lower tree‐ring δ 13 C values in very young trees (20 years) compared to medium‐aged trees (200 years) have been reported for pine in central Siberia (Fonti et al, 2018).…”

“…Such age‐related differences in climate response may be related to differences in photosynthetic rates, stomatal conductance, ratios of leaf area to sapwood, timing and duration of xylogenesis, and hydraulic capacity in old versus young trees (Farquhar et al, 1982; McCarroll & Loader, 2004; Rossi et al, 2008). Specifically, young trees have higher photosynthesis rates and stomatal conductance (Ryan et al, 2006; Ryan & Yoder, 1997), which results in their tree‐ring δ 13 C being more closely coupled with photosynthesis rates and stomatal conductance compared to old trees exposed to the same climate conditions (Fonti et al, 2018; see also section 4.1).…”

“…For instance, age‐dependent climate‐growth relationships have been detected in tree‐ring width in Schrenk spruce from the Tianshan mountains in China (Jiao et al, 2017; Wu et al, 2013). Progressive changes with tree age in growth rate, photosynthetic capacity, growing season, and other tree‐physiological factors may differentiate the influence of climate on old versus young trees for tree‐ring δ 13 C and δ 18 O, resulting in different plant physiological response and long‐term intrinsic water‐use efficiency ( iWUE ) variability (Esper et al, 2010; Fonti et al, 2018; Wu et al, 2018). For instance, Fonti et al (2018) found that tree‐ring δ 13 C of Scots pine from younger trees was more sensitive to climate compared to older trees in central Siberia.…”

“…Progressive changes with tree age in growth rate, photosynthetic capacity, growing season, and other tree‐physiological factors may differentiate the influence of climate on old versus young trees for tree‐ring δ 13 C and δ 18 O, resulting in different plant physiological response and long‐term intrinsic water‐use efficiency ( iWUE ) variability (Esper et al, 2010; Fonti et al, 2018; Wu et al, 2018). For instance, Fonti et al (2018) found that tree‐ring δ 13 C of Scots pine from younger trees was more sensitive to climate compared to older trees in central Siberia. However, other studies have not detected age‐related differences in climate response (e.g., tree‐ring δ 18 O in spruce from the Tibetan Plateau; Shi et al, 2011).…”

Direct and correlated responses to artificial selection for growth and water‐use efficiency in a Mediterranean pine

“…Future studies using molecular tools for genotyping will permit pedigree reconstruction and, therefore, more accurate estimates of realized heritability of iWUE (Gaspar et al, 2009). Other potential influences on the heritability estimates were (1) sampling for iWUE was performed in different tissues in the parental and offspring populations (wood and needles, respectively) (Klein et al, 2005;Hommel et al, 2014), (2) parental and offspring populations differed considerably in age at sampling, potentially leading to ontogenetic interferences (Castillo et al, 2018;Fonti et al, 2018;Cavender-Bares and Bazzaz, 2000), and (3) parental and offspring populations lived under different environmental conditions, possibly also contributing to different range scales of δ 13 C (Cernusak et al, 2013). Although we attempted to minimize the bias from this sampling variation by standardizing the variable separately for the parental and the offspring population, the realized heritability reported here for TABLE 1.…”