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Interpreting species‐specific variation in tree‐ring oxygen isotope ratios among three temperate forest trees
Author(s) -
SONG XIN,
CLARK KENNETH S.,
HELLIKER BRENT R.
Publication year - 2014
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12317
Subject(s) - temperate climate , isotopes of oxygen , oxygen 18 , isotope , stable isotope ratio , temperate forest , dendrochronology , cellulose , ecology , botany , biology , chemistry , paleontology , physics , quantum mechanics , nuclear chemistry , biochemistry
Although considerable variation has been documented in tree‐ring cellulose oxygen isotope ratios (δ 18 O cell ) among co‐occurring species, the underlying causes are unknown. Here, we used a combination of field measurements and modelling to investigate the mechanisms behind variations in late‐wood δ 18 O cell (δ 18 O lc ) among three co‐occurring species (chestnut oak, black oak and pitch pine) in a temperate forest. For two growing seasons, we quantified among‐species variation in δ 18 O lc , as well as several variables that could potentially cause the δ 18 O lc variation. Data analysis based on the δ 18 O cell model rules out leaf water enrichment (Δ 18 O lw ) and tree‐ring formation period (Δ t ), but highlights source water δ 18 O (δ 18 O sw ) as an important driver for the measured difference in δ 18 O lc between black and chestnut oak. However, the enriched δ 18 O lc in pitch pine relative to the oaks could not be sufficiently explained by consideration of the above three variables only, but rather, we show that differences in the proportion of oxygen exchange during cellulose synthesis (p ex ) is most likely a key mechanism. Our demonstration of the relevance of some species‐specific features (or lack thereof) to δ 18 O cell has important implications for isotope based ecophysiological/paleoclimate studies.