Isotopic composition ( δ 13 C, δ 18 O) in wood and cellulose of Siberian larch trees for early Medieval and recent periods

We related tree ring width (TRW) and isotopic composition ( δ 13 C, δ 18 O) of wood and cellulose from four larch trees ( Larix cajanderi Mayr.) to climate parameters. The material was sampled in northeastern Yakutia [70°N–148°E] for the recent (AD 1880–2004) and early Medieval (AD 900–1000) periods. During the recent period June, July, and August air temperatures were positively correlated with δ 13 C and δ 18 O of wood and cellulose, while July precipitation was negatively correlated. Furthermore, the vapor pressure deficit (VPD) of July and August was significantly correlated with δ 13 C of wood and cellulose, but VPD had almost no influence on δ 18 O. Comparative analyses between mean isotope values for the (AD 900–1000) and (AD 1880–2004) periods indicate similar ranges of climatic conditions, with the exception of the period AD 1950–2004. While isotopic ratios in cellulose are reliably related to climatic variables, during some periods those in whole wood showed even stronger relationships. Strong positive correlations between δ 18 O of cellulose and Greenland ice‐core (GISP2) data were detected for the beginning of the Medieval period (r = 0.86; p < 0.05), indicating the reliability of isotope signals in tree rings for large‐scale reconstructions.