Stable Isotopes in Tree Rings of Pinus heldreichii Can Indicate Climate Variability over the Eastern Mediterranean Region

Abstract

A long-term context is important for understanding past climatic variability. Although tree-ring widths (TRWs) are widely used as a proxy for reconstructing past climate, the use of annually-resolved values of δ13C and δ18O tree-ring stable isotopes (TRSIs) is increasing and may provide further valuable information. Here, we present a 487-year-long TRW chronology and 240-year-long TRSI chronology for Bosnian pine (Pinus heldreichii H. Christ) and compare them to each other. We demonstrate that both δ13C and δ18O values are better proxies for temperature, precipitation, and drought than TRW. The correlations between these climate parameters and TRSIs are strongest for the combined summer (JJA) period. The results of temporal and spatial field correlation indicate that TRSI chronologies are stable, reliable proxies for JJA precipitation reconstruction over the whole Balkan Peninsula and surrounding eastern Mediterranean region. However, the stability of the temperature signal of the both δ13C and δ18O chronologies declines after the 1950s. Our work supports the emerging evidence that TRSI data track climate variability more accurately than a conventional TRW approach and can be subsequently used for the reconstruction of past climate.

Wood anatomy and tree-ring stable isotopes indicate a recent decline in water-use efficiency in the desert tree Moringa peregrina

“…The first-differenced data for δ 18 O shows tendencies toward a common signal, which suggests that the trees are sensitive to a common environmental factor(s), e.g., drought. The range of δ 18 O in the present study (29.2-36.3‰) is consistent with that recorded for trees in semi-arid regions (Xu et al 2011;Qin et al 2015) or in the subtropical belt of the Eastern Mediterranean (Lukač et al 2021). It indicates uptake of enriched water sources or high isotopic enrichment of δ 18 O leaf water caused by high transpiration rates and subsequent assimilation (Sarris et al 2013;Treydte et al 2014).…”

Anthropogenic warming has exacerbated droughts in southern Europe since the 1850s

“…This difference may be because, in this study, we used the whole wood cellulose from black pine (Pinus nigra) trees, which would contain the climate signal recorded during the early growing season, whereas other studies used latewood cellulose from oak trees (Quercus robur) 20,30 . A negative relationship between our pine δ 18 O and spring-summer precipitation has been found in the adjacent regions of Montenegro, Bosnia, and Herzegovina 32 .…”

A Tree Ring Proxy Evaluation of Declining Causes in Pinus sylvestris L. and Pinus nigra J.F. Arnold in Northeastern Romania

“…Nowadays, various studies demonstrated strong species-specific sensitivity to environmental drivers evaluated through tree ring stable isotopes [21,22]. The tree rings stable carbon isotopes are widely used to retrospect trees response to climate change due to carbon dioxide increase.…”