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System Erde; 9, The main focus of the TERENO Northeastern German Lowland Observatory (TERENO-Northeast) is the regional impact of Global Change. Since 2011, the observatory has recorded changes in the geo-, hydro-, bio- and atmosphere at six main study sites. The year 2018, particularly in northeast Germany, was record-breaking in regard to dryness and heat. The mean temperature in Mecklenburg-Vorpommern was 2 °C above the long-term average and precipitation was very low at 440 mm (normally around 600 mm). The extreme summer of 2018 was a special opportunity for TERENO-Northeast to measure the regional effects of climate change. One of the consequences was the large number of forest fires, with one major fire destroying around 400 hectares. Other extreme reactions of the ecosystems were shown in TERENO-Northeast. For example, for the first time since its rewetting, Polder Zarnekov fell dry, with unpredictable consequences for the greenhouse gas exchanges. The forest ecosystems of Müritz National Park, on the other hand, survived the extreme summer surprisingly well, partly because the months before the drought were relatively damp. The research activities of TERENO-Northeast form an important basis to develop realistic options for improved adaptation strategies to the ongoing global change with its particular region-specific effects and challenges.

System Erde ; 7, Stable isotopes of the light elements Hydrogen (H), Carbon (C), Nitrogen (N), and Oxygen (O) are being measured in section 5.2 Climate Dynamics and Landscape Evolution at the GFZ in different terrestrial climate archives such as lake sediments, speleothems and tree rings. The stable isotope ratios of these elements reflect environmental conditions like precipitation, temperature, productivity and vegetation type. To translate isotope parameters into high-quality proxies of past climate and environmental variability, monitoring devices have been deployed which detect seasonal variations, pathways and distortions of stable isotope signals. Oxygen stable isotopes play a major role in paleoclimatology because of their broad variation and fractionation of 16O and 18O in water, carbonate and biological systems. In general, the isotopic ratios of oxygen isotopes reflect changes in atmospheric circulation systems which are important drivers for climate variability. Back through time, the variations of oxygen isotope ratios (18O/16O) in precipitation and their corresponding climate fingerprint are conserved in lake sediments, speleothems and tree rings. Oxygen isotope records from networks of these geoarchives allow local to regional assessments of past climate variability.

This publication is the outcome of the “Dendrosymposium 2002“, a tree-ring conference held from April 11th – 13th 2002 at the University of Bonn (Institute of Geography) and the Research Centre Jülich (Institute of Sedimentary Systems, ICG V). The aims of the German-language symposium were (i) to present the state of the art as well as new research perspectives in the different fields of dendrochronology, (ii) to stimulate further investigations and closer collaboration between different research groups and (iii) to strengthen dendrochronological sciences in central European research. About 50 scientists from Germany, Switzerland, Austria and The Netherlands attended the meeting. In total, 20 talks and 19 posters covering the topics (1) Archaeology, (2) Long Records, (3) Climatology, (4) Isotopes and Climate, (5) Isotopes and Plant Physiology, (6) Dendroecology, (7) Forest Dynamics at the Timberline and (8) Geomorphology were presented. The contributions clearly documented the topical and methodological progress that has been achieved in dendrochronology during the last years, including new approaches such as stable isotope analysis, dendrogeomorphology or ecophysiological aspects. The proceedings volume contains 21 extended abstracts. In order to give a comprehensive overview, shorter abstracts of participants, who did not submit a long version, are additionally included in their original language. Another important goal of the conference was the first meeting of the “Gesellschaft für Jahrringforschung” GJF (“Association of Tree Ring Research” ATR) founded in September 2001 in Davos. Gerhard Schleser (Research Centre Jülich) and Esther Jansma (National Service for Archaeological Heritage/The Netherlands) have been elected for a period of two years as the president and vice president of the Association, respectively. Considering his outstanding scientific and educational merits Fritz Schweingruber was assigned as honorary president. Members of the advisory council are Achim Bräuning (Stuttgart), Jan Esper (Birmensdorf), Holger Gärtner (Birmensdorf), Karl-Uwe Heussner (Berlin), Hans-Peter Kahle (Freiburg), Klaus-Felix Kaiser (Birmensdorf), Kurt Nicolussi (Innsbruck), Constantin Sander (Heidelberg), Matthias Saurer (Villingen), Burkhard Schmidt (Köln), Uwe Treter (Erlangen) and Matthias Winiger (Bonn). More detailed information is available on-line at the ATR-Homepage: $\textbf{www.tree-ring.org}$ Finally, sincere thanks are given to all the participants of the meeting, who made it a lively forum with much exchange of ideas, including the authors of the submitted papers and last but not least to the organizing team of the symposium Burkhard Neuwirth (Bonn), Holger Gärtner (Birmensdorf), Kerstin Treydte (Jülich), Gerd Helle (Jülich) and Jan Esper (Birmensdorf).