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An ultra-long tree-ring width chronology (9111 years long, 7109 BC to AD 2002) has been established based on the analysis and dating of 1432 subfossil/dry dead wood samples and cores from 335 living trees. The material was collected from treeline or near-treeline sites (c. 2000 to 2400 m a.s.l.) mainly in the Eastern Alps. The availability of preserved samples through time at high altitudinal sites is influenced by Alpine forest history and is partly climatically controlled, as shown by comparisons of the sample depth record of the Eastern Alpine Conifer Chronology (EACC) with the Holocene glacier record. The similarity of variations over time between the sample depth of the chronology and the mid-Holocene GISP2 10Be record suggest a relationship between sample depth and solar activity. The Eastern Alpine Conifer Chronology has already been used as a dating base in environmental studies, eg, on glacier fluctuations, as well as in archaeological studies. [ABSTRACT FROM AUTHOR]

Subfossil pollen from two bogs in temperature-sensitive, high-altitude regions were analysed in order to reconstruct early- to mid-Holocene summer temperature fluctuations in the Eastern Alps. The pollen records showed four centennial-scale cooling intervals with low growing-season temperatures, resulting in decreasing pollen production and/or lower treeline position during the period 9000–6000 cal. BP. For the first time, the 8200 cal. BP cold event and an equivalent to the Misox cold phase in the Swiss Alps were detected in the Eastern Alps. The oscillations recorded in the pollen curves for Swiss stone pine (Pinus cembra) and sedges (Cyperaceae) at c. 8200 cal. BP match, in time and magnitude, the δ18O excursion in the Greenland GRIP ice-core record as well as sea-surface cooling in the North Atlantic. The close congruence between the pollen records covering 3000 years and climate proxy-data from both Hemispheres indicates that large-scale environmental changes, possibly caused by North Atlantic freshwater pulses and/or fluctuations in solar activity, caused decreases in pollen production and/or treeline shifts in the Alps. Although the 8200 cal. BP climatic deterioration was of a global character, its impact on biological productivity of temperature-sensitive sites at high altitude has only rarely been demonstrated. The data indicate that pollen analyses near and above the timberline within high-altitude, herb-dominated plant communities are of considerable and yet largely unexplored potential to detect abrupt short-term as well as long-term climatic variations. [ABSTRACT FROM AUTHOR]

During recent years a number of fragments of Pinus cembra and Larix decidua as well as peat were found in front of the tongue of the Pasterze Glacier in the Eastern Alps. These were washed out by the stream from under the present ice. The wood originates from trees which reached ages of up to 400 years or more. Radiocarbon dating shows them to come from the early Holocene. They indicate that between cal. bc 8100 and cal. bc 6900 the Pasterze Glacier was smaller than at present. The Pasterze Glacier advanced around cal. bc 6900. A lump of peat shows that around cal. bc 6300 at the latest the Pasterze Glacier was again smaller than today. The radiocarbon age of the fulvic acid fraction of the peat suggests that growth could have continued until cal. bc 5430–5080. Further wood samples, dated to around cal. bc 4800 and cal. bc 3800, show that at these times the Pasterze Glacier was smaller than at present. The Pasterze Glacier had a relatively limited extent over long periods in the early Holocene. Thus mostly favourable climatic conditions can be inferred for these time periods. [ABSTRACT FROM AUTHOR]