Research

• Eurasian Peatlands
• Climate/boreal shrubs
• Dynamic of the treeline
• Palaeoclimate
• Study sites
• Cooperation

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This webpage will not be updated anymore.

Please refer to www.botanik.uni-greifswald.de/laoek.html

Dynamic of the northern and elevational treeline

Northern and upper elevational treelines are generally controlled by a temperature deficit, often modified by local conditions (such as permafrost occurrence). Recent studies however, identified a shift from temperature to moisture control in many places (such as Alaska and China), non-linear relationships between climate and tree growth, sub-population behaviour at northern treeline and the “divergence effect” (an underestimation of recent warming trends by tree ring based proxies).

Our approach to these questions is to try to develop a better ecological understanding of how a tree grows and what interactions take place between tree and these extreme environments. Based on this ecological understanding, we try to tackle the issue of using tree rings for climate reconstruction.

At the moment, we are working on the following topics:

1. Interaction between treeline and permafrost (NW Russia, Alaska)
2. Divergent growth at treeline – the search for sub-populations around the globe
3. What are the ecological reasons for the “divergence effect”
4. Develop climate reconstructions, taking into account sub-population behaviour
5. Develop a record of climate extremes from northern treeline in Russia (Krupp Fellow Marina Gurskaya)
6. Recent treeline dynamics in Nepal (M.Sc. project Erica Udas)

Cooperations:

University of Alaska Fairbanks, U.S.A., G.P. Juday, V. Barber
Stockholm University, S. Holzkämper
University of Nottingham, G.B., P. Crittenden, Tanja Sanders
Lamont Doherty Tree Ring Lab, U.S.A., Rosanne D’Arrigo
U.S.G.S. Menlo Park, Jennifer Harden