High elevation mountain forests in the European Alps are strongly affected by climate change. In this study we aimed to investigate the long- and short-term effects of climate on radial stem growth and tree hydraulics of the two dominant tree species at the forest line of the Eastern central Alps, European larch (Larix decidua Mill. and Swiss stone pine (Pinus cembra L). To this end, we analyzed tree ring widths from stem cores from five sites between 1990 and 2320 m above sea level (a.s.l.) and measured sap flow for three years and radial stem variation for four years at three sites between 1990 and 2100 m a.s.l. in an inner alpine dry valley in Northern Italy. We found that tree ring width of larch responded stronger to temperature and increased more with warming in the last decades than in Swiss stone pine. In the short term, low soil moisture reduced sap flow during the summer in Swiss stone pine but not in larch. Additionally, air vapor pressure deficit clearly reduced the number of days with radial stem growth in Swiss stone pine, leading to lower annual growth than in larch. Consequently, larch at high elevation might actually benefit from climate change at the expense of Swiss stone pine.

欧洲阿尔卑斯山的高海拔山地森林受到气候变化的强烈影响。在这项研究中，我们旨在调查气候对中部东部阿尔卑斯山林线的两种优势树种欧洲落叶松（落叶松落叶松和瑞士石）径向茎生长和树木水力的长期和短期影响松树 ( Pinus cembra)L)。为此，我们分析了 1990 年至 2320 米海拔 (asl) 之间五个地点的树干芯的树轮宽度，并在 1990 年至 2100 米 (asl) 之间的三个地点测量了三年的树液流和四年的径向茎变化意大利北部的一个内高山干燥山谷。我们发现，在过去的几十年里，落叶松的年轮宽度对温度的反应更强，并且随着变暖而增加的幅度大于瑞士石松。在短期内，低土壤水分减少了瑞士石松的夏季液流，但落叶松没有。此外，空气蒸汽压不足明显减少了瑞士石松径向茎生长的天数，导致年生长低于落叶松。因此，高海拔落叶松实际上可能会以牺牲瑞士石松为代价从气候变化中受益。