Climate signals in carbon and oxygen isotope ratios ofPinus cembratree‐ring cellulose from the Călimani Mountains, Romania

Abstract

We analyse annually resolved tree‐ring stable carbon (δ13C) and oxygen (δ18O) isotopic chronologies from Swiss stone pine (Pinus cembra L.) in Romania. The chronologies cover the period between 1876 and 2012 and integrate data from four individual trees from the Calimani Mts in the eastern Carpathians where climatic records are scarce and starts only from 1961. Calibration trials show that the δ13C values correlate with local April–May relative humidity and with regional to larger scale (European) summer precipitation. δ18O correlates significantly with local relative humidity, cloud cover, maximum temperature, as well as European scale drought conditions. In all cases, the climate effects on δ13C values are weaker than those recorded in the δ18O data, with the latter revealing a tendency toward higher (lower) values of δ18O during extremely dry (wet) years. The most striking signal, however, is the strong link between the interannual δ18O variability recorded in the Calimani Mts and large‐scale circulation patterns associated with North Atlantic and Mediteraneean Sea sea surface temperatures. High (low) values of δ18O occur in association with a high (low) pressure system over the central and eastern part of Europe and with a significantly warmer (colder) Mediterranean Sea surface temperature. These results demonstrate the possibility of using tree ring oxygen isotopes from the eastern Carpathians to reconstruct regional drought conditions in eastern Europe on long‐term time scales and larger scale circulation dynamics over the preinstrumental periods.

Stable Isotopes Reveal Climate Signal Hidden in Tree Rings of Endemic Balkan Pines

“…The presented δ 13 C chronology is, to the best of our knowledge, the first stable carbon isotope chronology for endemic Balkan pines (P. heldreichii and P. peuce). Our composite P. heldreichii and P. peuce stable carbon isotope chronology has a similar climate signal in δ 13 C in tree-rings as δ 13 C chronologies from the Carpathians [21], Corsica [22,23], or the south-eastern Alps [24]. Even though our composite δ 13 C chronology correlates best with cloudiness, we decided to test a potential climate reconstruction model of summer temperatures, since the cloudiness dataset is short, with some missing data.…”

“…However, there are δ 13 C chronologies for other tree species in the wider region, although the number of δ 13 C chronologies is smaller than in Western Europe, Fennoscandia, or parts of the Mediterranean region. Nagavciuc et al [21] developed a stable carbon and oxygen isotope chronology for Pinus cembra for the eastern Carpathian timberline and found that δ 13 C was negatively correlated with summer precipitation and three-month SPEI (Standardized Precipitation-Evapotranspiration Index) index. Szymczak et al [22,23] developed a 560-year summer temperature reconstruction for Corsica (France) based on a stable carbon isotope from Pinus nigra tree-rings.…”

Alpine Holocene tree-ring dataset: age-related trends in the stable isotopes of cellulose show species-specific patterns

“…Holocene wood sections were available at the Department of Geography of the University of Innsbruck, where the Eastern Alpine Conifer Chronology (EACC) has been established on the basis of calendar-dated tree-ring-width series (Nicolussi et al, 2009). We have utilized a large number of these sub- T. Arosio et al: Alpine Holocene tree-ring dataset Figure 1.…”

“…Map of the location of the 29 sampling sites (© Google Maps 2020): they are situated in the Swiss, the Austrian, and the Italian Alps. Information on each site is given in Table 1. fossil wood samples that cover nearly the whole Holocene (Nicolussi et al, 2009). They belong to the deciduous larch (Larix decidua Mill.)…”

“…Here we investigated the presence of age trends by utilizing a stable-isotope tree-ring database, which was established on the basis of the Eastern Alpine Conifer Chronology (Nicolussi et al, 2009): (i) the database consists of samples of mainly subfossil wood from 201 trees; (ii) the isotope samples are not pooled; (iii) the isotope time series, with up to multicentennial length, continuously cover the last ca. 9000 years; (iv) the database utilizes two different species, deciduous larch and evergreen cembran pine; (v) the wood material was collected at different tree line sites; and (vi) the database contains only 17 trees with rings that grew after the Industrial Revolution.…”