Climatically Driven Holocene Glacier Advances in the Russian Altai Based on Radiocarbon and OSL Dating and Tree Ring Analysis

Analysis of new chronological data, including 55 radiocarbon, 1 OSL, and 8 dendrochronological dates, obtained in the upper reaches of trough valleys within the Katun, North Chuya, South Chuya, and Chikhachev ranges, together with the 55 previously published ones, specifies climatically driven glacier dynamic in the Russian Altai. Available data refute the traditional concept of the Russian Altai Holocene glaciations as a consecutive retreat of the Late Pleistocene glaciation. Considerable and prolonged warming in the Early Holocene started no later than 11.3–11.4 cal kBP. It caused significant shrinking or even complete degradation of alpine glaciers and regeneration of forest vegetation 300–400 m above the modern upper timber limit. Stadial advances occurred in the middle of the Holocene (4.9–4.2 cal kBP), during the Historical (2.3–1.7 cal kBP), and the Aktru (LIA thirteenth–nineteenth century) stages. New radiocarbon ages of fossil soils limited glaciers expansion in the Middle Holocene by the size of the Historical moraine. Lesser glacial activity between 5 and 4 cal kBP is also supported by rapid reforestation in the heads of trough valleys. Glaciers advance within the Russian Altai, accompanied by accumulation of the Akkem moraine, could have occurred at the end of the Late Pleistocene.

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NEW CONSTRAINTS ON THE TIMING OF LATE PLEISTOCENE GLACIATION AT TWIN LAKES IN THE UPPER ARKANSAS RIVER VALLEY, COLORADO: INITIAL RESULTS

10.1130/abs/2016ne-272787 ◽

2016 ◽

Author(s):

Avriel D. Schweinsberg ◽

◽

Jason Briner ◽

Joseph M. Licciardi ◽

Ralph R. Shroba

Keyword(s):

Late Pleistocene ◽

River Valley ◽

Pleistocene Glaciation ◽

Arkansas River ◽

Initial Results ◽

Arkansas River Valley

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TREE-RING ANALYSIS, A TOOL TO ASSIST IN DATING OF SUBFOSSIL FORESTS KILLED BY GEOLOGIC EVENTS—VICTIM TREE EXAMPLES FROM MOUNT RAINIER LAHARS AND THE BONNEVILLE LANDSLIDE, WASHINGTON AND OREGON, USA

10.1130/abs/2020am-359506 ◽

2020 ◽

Author(s):

Patrick Pringle ◽

Keyword(s):

Tree Ring ◽

Tree Ring Analysis ◽

Mount Rainier ◽

Ring Analysis

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Tree-Ring Analysis of Intermediate Hawthorn (Crataegus media Bechst.) in NW Poland

Forests ◽

10.3390/f12010029 ◽

2020 ◽

Vol 12 (1) ◽

pp. 29

Author(s):

Anna Cedro ◽

Bernard Cedro

Keyword(s):

Tree Ring ◽

Tree Rings ◽

Agricultural Landscape ◽

Positive Influence ◽

Dominant Factor ◽

Incremental Growth ◽

High Precipitation ◽

Ring Analysis ◽

Uncultivated Land ◽

Nw Poland

Intermediate hawthorn (Crataegus × media Bechst.) is broadly distributed in Europe but very rarely examined by dendrochronologists. In NW Poland, it is one of three naturally occurring hawthorn species, growing mainly at forest margins, along roads, in mid-field woodlots, and on uncultivated land. Biocenotically, it is a very valuable species. This study aimed to determine the age of trees, tree-ring dynamics, and growth–climate relationship for intermediate hawthorn. Signature years were also determined. Samples for analysis were collected from 22 trees growing in a typical agricultural landscape in a monospecific mid-field woodlot comprised of several hundred specimens of various ages and forms (shrubs and trees). Using classic methods of dendrochronological dating, a 40-year long chronology spanning 1981–2020 was constructed. The radial growth rate of intermediate hawthorn is comparable to other tree species forming stands in NW Poland and equals 2.41 mm/year. Considerable intersubject variability is noted, from 1.48 to 4.44 mm/year. The chronology was also used for dendroclimatological analyses, including correlation and response function and signature years. Of the meteorological parameters analyzed, annual incremental growth in hawthorn is the most strongly shaped by precipitation totals from May to August of the current vegetation year: high rainfall favors the formation of wide tree-rings. Statistically significant growth–climate relationships were also obtained for winter months (December of the preceding vegetation year, January and February), for which period negative correlation and regression values are noted for air temperature and insolation. Furthermore, high precipitation, low-temperature and low insolation late in the preceding vegetation year (especially in August) make a positive influence on the condition of trees in the upcoming growing season. Signature year analysis clearly pointed to precipitation as the dominant factor in shaping tree-rings in the studied hawthorn population. As there are no dendrochronological papers concerning indigenous hawthorn species, future studies should be expanded to include diverse geographic locations and habitat conditions and should include all three species of hawthorn occurring in Poland.

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