Dendrochronologia 64 (2020) 125763 Available online 24 September 2020 1125-7865/© 2020 Elsevier GmbH. All rights reserved. Original article Climatic responses of Pinus brutia along the Black Sea coast of Crimea and the Caucasus V.V. Kukarskih a, b , N.M. Devi a, *, A.Y. Surkov a , M.O. Bubnov a , L.A. Gorlanova a , Y.A. Ekba c , R. M. Hantemirov a, b a Institute of Plant and Animal Ecology, Ural Branch of the Russian Academy of Sciences, 620144, Ekaterinburg, Russia b Department of History of the Institute of Humanities, Ural Federal University, 620000, Ekaterinburg, Russia c Institute of Ecology, Abkhazian Academy of Sciences, 384900, Sukhum, Abkhazia A R T I C L E INFO Keywords: Pinus brutia Radial growth Climatic response PDSI Crimea Caucasus ABSTRACT Pinus brutia var. pityusa (Steven) Silba (Calabrian pine) is considered a vulnerable species because of reductions in its population sizes linked to habitat decline in recent decades. Global warming alongside the collateral modifcation of precipitation regimes may markedly affect the distribution ranges of this species. In this dendroecological study, we identifed the most infuential climatic factors affecting the radial growth of P. brutia on the northern and eastern coasts of the Black Sea among the northern refugia of this species. Chro- nologies from fve sites located on the Crimea Peninsula and the Caucasian coast and exposed to varying climatic conditions were used in this analysis. The study of environmental factors controlling the growth of P. brutia trees in the coastal populations of Crimea and the Caucasus revealed that within the longitudinal transect, which encompasses a specifc range of climatic conditions, correlations between climate and the growth of P. brutia under analogous orographic conditions are similar. Aridisation of the dry Crimean climate in 1981–2012 led to an increase in the tree growth response. In the same period, populations of P. brutia trees growing in the subtropical climate of the Black Sea coast exhibited a weakened growth response to the point of disappearance. The northern populations of P. brutia, which are at the climatic limit of the species’ distribution, are exposed to a high risk of increasing climate aridisation. Our fndings could provide useful information for further research on the effects of climate change on Black Sea coastal forest ecosystems. 1. Introduction P. brutia is a drought-tolerant, fast-growing, and widely distributed coniferous species native to the eastern coast of the Mediterranean re- gion, extending from Greece to Syria (Boydak, 2004). Several pine species growing along the northern and northeastern coasts of the Black Sea, including Pinus pithyusa Stev., Pinus stankewiczii Sukac., and Pinus eldarica Medwed., were categorised as subspecies of P. brutia by Nahal (1983) and as varieties of P. brutia by Critchfeld and Little (1966) and Vidaković (1991). However, these species are now classifed as being among the same species and populations despite their phenotypic dif- ferences (Semerikova and Semerikov, 2020). Trees growing on steep sea-facing slopes usually have wide crowns, curved stems, and long and coarse branches, whereas those growing on fat slopes usually have narrow and dense crowns and long, straight stems with small branches (Alemdag, 1962; Arbez, 1974; Isik and Isik, 1999). P. brutia forests provide important environmental benefts and services, including soil protection, biodiversity conservation and climate change mitigation and adaptation. Small refugia of this species have been preserved on the eastern and northern shores of the Black Sea (Conkle et al., 1988; Yena et al., 2005), where this species grows at the limit of its resistance to low winter temperatures. P. brutia is a ther- mophilous species that prefers lowland semihumid and humid sites with mean annual temperatures of 12–20 ◦ C (Boydak, 2004; Qu´ ezel and Barbero, 1992). In addition, it is highly drought resistant, has a deep rooting zone, and can grow in areas with mean annual rainfall as low as 400 mm (Nahal, 1983). The unique growth characteristics of P. brutia make it one of the most promising pine species in arid regions. In Crimea, P. brutia grows under the drought-prone conditions of the Mediterranean climate and can be found on steep slopes with poor soil * Corresponding author. E-mail address: nadya@ipae.uran.ru (N.M. Devi). Contents lists available at ScienceDirect Dendrochronologia journal homepage: www.elsevier.com/locate/dendro https://doi.org/10.1016/j.dendro.2020.125763 Received 7 May 2020; Received in revised form 11 September 2020; Accepted 18 September 2020