EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Climate warming does not adequately translate to increased radial stem growth of coniferous species along the Alpine treeline ecotone

Walter Oberhuber1, Ursula Bendler1, Vanessa Gamper1, Jacob Geier1, Anna Hölzl1, Werner Kofler1, Hanna Krismer2, Barbara Waldboth1, and Gerhard Wieser3
Walter Oberhuber et al.
  • 1Department of Botany, University of Innsbruck, Botany, Innsbruck, Austria (;
  • 2Department of Forest- and Soil Sciences, Institute of Silviculture, University of Natural Resources and Life Sciences, Vienna, Austria (
  • 3Division of Alpine Timberline Ecophysiology, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Innsbruck, Austria (

It is well established, that tree growth at high elevations is mainly limited by low temperature during the growing season and climate warming was frequently found to lead to more growth and expansion of trees into alpine tundra. However, dendroclimatological studies revealed contradictory growth response to recent climate warming at the upper elevational limit of tree growth, and transplant experiments unveiled that high elevation tree provenances are not adequately benefiting from higher temperatures when planted at lower elevation. We therefore re-evaluated growth response of trees to recent climate warming by developing tree ring series of co-occurring conifers (Swiss stone pine (Pinus cembra), European larch (Larix decidua), and Norway spruce (Picea abies)) along several altitudinal transects stretching from the subalpine zone to the krummholz-limit (1630–2290 m asl; n=503 trees) in the Central European Alps (CEA). We evaluated whether trends in basal area increment (BAI) are in line with two phases of climate warming which occurred from 1915–1953 and from mid-1970s until 2015. We expected that BAI of all species shows an increasing trend consistent with distinct climate warming during the study period (1915–2015) amounting to >2 °C. Although enhanced tree growth was detected in all species in response to climate warming, results revealed that at subalpine sites (i) intensified climate warming since mid-1970s did not lead to corresponding increase in BAI, and (ii) increase in summer temperature primarily favored growth of Norway spruce, although Swiss stone pine dominates at high altitude in the CEA and therefore was expected to mainly benefit from climate warming. At treeline BAI increase was above the determined age trend in all species, whereas at the krummholz-limit only deciduous larch showed minor growth increase. We explain missing adequate growth response to recent climate warming (i) by strengthened competition for resources (primarily nutrients and light) in increasingly denser stands at subalpine sites leading to changes in carbon allocation among tree organs, and (ii) by frost desiccation injuries of evergreen tree species at the krummholz-limit. Our findings indicate that tree growth response to climate warming at high elevation is possibly nonlinear, and that increasing competition for resources and the influence of climate factors beyond the growing season impair stem growth. 

How to cite: Oberhuber, W., Bendler, U., Gamper, V., Geier, J., Hölzl, A., Kofler, W., Krismer, H., Waldboth, B., and Wieser, G.: Climate warming does not adequately translate to increased radial stem growth of coniferous species along the Alpine treeline ecotone, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8232,, 2020


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