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Developing millennial tree-ring chronology for Turku (Åbo) and comparing palaeoclimatic signals inferred from archaeological, subfossil and living Pinus sylvestris data in Southwest Finland

Helama Samuli, Ratilainen Tanja, Ruohonen Juha, Taavitsainen Jussi-Pekka

Studia Quaternaria

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2024

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Vol. 41, Nr 1

1--11

EN

Archaeological and living tree data were used to construct tree-ring chronologies over the medieval (AD 1183–1430) and recent (AD 1812–2020) periods in Turku, which is historically an important population centre in Southwest Finland and the country. Comparisons between the two tree-ring assemblages, and between the previously built chronologies from the Åland (historical timber) and Tavastia (lacustrine subfossils and living trees) sites, provided ways of understanding the growth patterns and their linkages to climatic, environmental, and edaphic factors. Tree growth in and around Turku was affected by warm-season precipitation and winter temperature. Similar relationships were previously evident also in the Åland tree rings, whereas the data from a wetter Tavastia site did not exhibit similar precipitation signal. The site conditions influence also the correlations which are higher between Turku and Åland than between Turku and Tavastia chronologies. Construction of long continuous chronology is impaired by human-related activities, the Great Fire of Turku in 1827 and logging, which have diminished the availability of dead and living-tree materials, respectively. These conditions lead to hardships of filling the gap between the medieval and recent periods and updating the archaeological datasets with compatible living-tree data, which are both demonstrated by our results.

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Instability of the environment at the end of the Eemian Interglacial as illustrated by the isopollen maps for Poland

Kupryjanowicz M., Granoszewski W., Nalepka D., Pidek I. A., Walanus A., Balwierz Z., Fiłoc M., Kołaczek P., Majecka A., Malkiewicz M., Nita M., Noryśkiewicz B., Winter H.

Geological Quarterly

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2016

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Vol. 60, No. 1

225--237

EN

Many terrestrial pollen profiles from Poland (and a few pollen records from other parts of Central Europe) show the end of the last interglacial (Eemian, MIS 5e) to have been characterized by climatic and environmental instability. This is expressed by a strong, rapid cooling in the middle part of the pine phase ending this interglacial (E7 regional pollen assemblage zone), and then a re-warming at the very end of this phase, immediately before the transition to the glacial conditions of the last glaciation (Vistulian, Weichselian, MIS 5d). We have characterized the regional distribution of these climatic fluctuations in Poland on the basis of isopollen maps prepared for the Eemian Interglacial based on palynological data from 31 Polish pollen profiles. These maps show unequivocally that the intra-interglacial cooling at the end of the Eemian Interglacial was a transregional phenomenon, which was reflected very clearly by a temporary openness of vegetation across the whole of Poland. It was associated with a distinct decrease in pine forest areas and an increase in birch forests and open communities of cold steppe type with a domination of Artemisia. The pronounced climate and environment instability during the last phase of the Eemian Interglacial may be consistent with it being a natural phenomenon, characteristic of transitional stages. Taking into consideration the currently observed global warming, coinciding with a natural cooling trend, the study of such transitional stages is important for understanding the underlying processes of climate change.

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12 millennia of climatic and human induced vegetation changes in the lower san valley near Jarosław (se poland) in the light of Pollen analysis

Kołaczek P.

Studia Quaternaria

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2011

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Vol. 28

25-39

EN

Vegetation changes in the Lower San Valley near Jarosław are reconstructed from the Younger Dryas to the present time on the basis of palynological analysis of the peat core. The pollen profile came from a an old riverbed and was supplemented by radiocarbon datings. The Younger Dryas and early Preboreal vegetation was characterised by a high proportion of forest communities with pine (Pinus sylvestris and P. cembra) and birch (Betula), while patches of open area were dominated by the steppe with Artemisia. Climatic amelioration during the Preboreal chronozone led to the rapid spread of elm (Ulmus), which was probably a dominant taxon on the lowest terraces of the valley. Terrestrialization of the water body existing in the palaeomeaner and the subsequent beginning of peat accumulation caused a deterioration in pollen preservation. Hence, the interpretation of the profile section spanning the period between the Boreal and Subatlantic chronozones was seriously disturbed due to selective corrosion and the overrepresentation of Pinus sylvestris type and Filicales monolete sporomorphs. Between ca. 336 and 1152 AD fluctuations in woodland cover were recorded. Important components in those forests, despite the domination of Pinus sylvestris, were Quercus, Carpinus betulus, Fagus sylvatica and Abies alba. The first pollen grains of cereals (Cerealia type) were found before ca. 1605-1414 BC and may be attributed to the agricultural activity of the Neolithic and/or early Bronze tribes. Periods of strong deforestation caused by humans were probably related to the time when the Tarnobrzeska Group of the Lusatian Culture and the Przeworska Culture were active. The first groups of Slavs did not significantly influence the environment, but the subsequent development of those groups led to more visible deforestation, which was triggered after the establishment of Jarosław in the 11th century AD.

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Przyrodnicza historia Gniezna - plemiennego ośrodka kultu i centrum wczesnopiastowskiego państwa polskiego Civitas Schinesghe

Makohonienko M., Kara M., Koszałka J.

Landform Analysis

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2011

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Vol. 16

39-45

EN

The stronghold complex in Gniezno located on the Lech's Hill belonged to the main centers of the early Polish State described for the first time in historical documents as Civitas Schinesghe - the Gniezno State. Recent archaeological studies indicate that the site on Lech's Hill was originally a tribal cult center. Palaeoecological studies provided records of environmental changes and cultural landscape development in the prehistoric periods and early historical times. Reconstructed changes of floristic diversity correlate well with the cultural processes.

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Lithology and biostratigraphy of the Holocene succession of Lake Kuži, Vidzeme Heights (Central Latvia)

Kangur M., Koff T., Punning J.-M., Vainu M., Vandel E.

Geological Quarterly

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2009

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Vol. 53, No 2

199-208

EN

Holocene sediment profile from a paludified near-shore area of Lake Kńži (Vidzeme Heights, Central Latvia) was investigated using lithological and palaeobotanical (pollen and macrofossil analysis) methods and accelerator mass spectrometry AMS 14C dating. The results of this first comprehensive study of a Holocene sed i ment core from the Vidzeme Heights indicate that at the beginning of the Early and at the end of the Late Holocene the lake level was low and fen peat accumulated around the lake. From ca. 9000 BP up to 1500 BP the mire was flooded and gyttja with interlayers of sand and peat accumulated. The water level fluctuations are clearly represented in the lithological succession and pollen spectra. We compared the L. Kńži pollen diagram with well-studied sites from the Haanja Heights, which have a similar genesis. The most obvious difference in these diagrams is the earlier appearance (9200 BP) of Picea pollen in the L. Kńži profile and its dominance up to 1000 BP. Compara tive analysis of the lithology and pollen spectra from L. Kńži and reference profiles from the Haanja Heights indicate the importance of broad regional factors in influencing the pollen spectra.

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Postglacial development of vegetation in the vicinity of the Wigry Lake

Kupryjanowicz M.

Geochronometria

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2007

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Vol. 27

53-66

EN

The Late Glacial and Holocene development of vegetation in the vicinity of the Wigry Lake is reconstructed using pollen analysis. The Late Glacial sediments include the Allerod and Younger Dryas chronozones. The Holocene section is complete. Pollen data combined with archaeological evidence and radiocarbon dating permit the recognition and characterisation of human influence on the local plant cover caused by settlers of Mesolithic and Neolithic cultures, by west Balts, by Grand Dukes of Lithuania and by Cameldolites order. On the basis of pollen analysis the development of aquatic and mire vegetation in the Wigry Lake is described.