ORIGINAL PAPER Climate signals in the ring widths and stable carbon, hydrogen and oxygen isotopic composition of Larix decidua growing at the forest limit in the southeastern European Alps Polona Hafner • Iain Robertson • Danny McCarroll • Neil J. Loader • Mary Gagen • Roderick J. Bale • Ho ¨gne Jungner • Eloni Sonninen • Emmi Hilasvuori • Tom Levanic ˇ Received: 21 February 2011 / Revised: 28 June 2011 / Accepted: 1 July 2011 / Published online: 17 July 2011 Ó Springer-Verlag 2011 Abstract The southeastern border of the European Alps is not well resourced with high-resolution climate proxies and experiences a distinct climatic regime from the northern and western Alpine zones. Here, we present new high-resolution climatic proxies (AD 1907–2006) from ring widths and stable carbon (d 13 C), non-exchangeable hydrogen (d 2 H) and oxygen (d 18 O) isotope ratios of cellulose extracted from Larix decidua tree rings, growing at the forest limit in the southeastern European Alps (Slovenia). d 13 C, d 2 H and d 18 O are strongly (p \ 0.001) and positively correlated with each other. June temperature has the strongest control on tree ring width (TRW), while later summer conditions (July– August) influence the stable isotope composition. All four proxies are strongly correlated (r [ 0.4; p \ 0.001) with summer temperature and also sunshine hours, while pre- cipitation has less impact. A combination of TRW and d 13 C provides the greatest potential for reconstructing past temperatures (June–August) with significant (p \ 0.001) correlations with gridded temperatures extending across a very large part of southern and western Europe west of the Carpathian Mountains. The water isotopes (oxygen and hydrogen) record conditions in the Adriatic and Mediter- ranean, which are the source area for the air masses that bring precipitation to this region giving strong correlations with temperatures in southern Italy and the western part of the Balkan Peninsula. Combining proxies with different spatial and temporal signals allows the strength and spatial footprint of climate signals to be enhanced. These findings open new perspectives for climate reconstruction in the southeastern European Alps and Western Balkans. Keywords Dendroclimatology Á Dendrochronology Á European larch Á Slovenia Á Tree ring Á Stable isotopes Introduction European larch (Larix decidua Mill.) is a long-lived and temperature-sensitive (Rolland et al. 1998, Carrer and Urbinati 2006) species distributed over the European Alps, Tatra Mountains, Poland and the Sudetan region (Maier 1992). The mountains of Slovenia, in the southeastern corner of the European Alps, represent the southeastern border of the Alpine Larix decidua population (EUFORGEN 2009). Since any changes in tree growth and ecological equilibrium are likely to occur first in stands at the boundaries of the ecological range of a species (Tessier et al. 1997), this area offers potential for reconstructing past changes in climate and environment and for predicting the impact of environ- mental change on the forest ecosystem. One of the concerns about using larch as a palaeoclimatic archive is the regular occurrence of the larch bud-moth (Zeiraphera diniana Gn.) Communicated by G. Wieser. P. Hafner (&) Á T. Levanic ˇ Department of Yield and Silviculture, Slovenian Forestry Institute, Vec ˇna pot 2, 1000 Ljubljana, Slovenia e-mail: polona.hafner@gozdis.si I. Robertson Á D. McCarroll Á N. J. Loader Á M. Gagen Á R. J. Bale Department of Geography, Swansea University, Swansea SA2 8PP, UK R. J. Bale Department of Archaeology, University of Wales, Trinity Saint David, Lampeter SA48 7ED, UK H. Jungner Á E. Sonninen Á E. Hilasvuori Dating Laboratory, Finnish Museum of Natural History, University of Helsinki, P.O. Box 64, 00014 Helsinki, Finland 123 Trees (2011) 25:1141–1154 DOI 10.1007/s00468-011-0589-z