Dendrochronological Data Research Articles

ABSOLUTE CHRONOLOGY AT THE WATERLOGGED SITE OF LA DRAGA (LAKE BANYOLES, NE IBERIA): BAYESIAN CHRONOLOGICAL MODELS INTEGRATING TREE-RING MEASUREMENT, RADIOCARBON DATES AND MICRO-STRATIGRAPHICAL DATA

ABSTRACTSixty-two 14C dates are analyzed in combination with a recently established local floating tree-ring sequence for the Early Neolithic site of La Draga (Banyoles, northeast Iberian Peninsula). Archaeological data, radiometric and dendrochronological dates, as well as sedimentary and micro-stratigraphical information are used to build a Bayesian chronological model, using the ChronoModel 2.0 and OxCal 4.4 computer programs, and IntCal 2020 calibration curve. The dendrochronological sequence is analyzed, and partially fixed to the calendrical scale using a wiggle-matching approach. Depositional events and the general stratigraphic sequence are expressed in expanded Harris Matrix diagrams and ordered in a temporal sequence using Allen Algebra. Post-depositional processes affecting the stratigraphic sequence are related both to the phreatic water level and the contemporaneous lakeshore. The most probable chronological model suggests two main Neolithic occupations, that can be divided into no less than three different “phases,” including the construction, use and repair of the foundational wooden platforms, as well as evidence for later constructions after the reorganization of the ground surface using travertine slabs. The chronological model is discussed considering both the modern debate on the Climatic oscillations during the period 8000–4800 cal BC, and the origins of the Early Neolithic in the western Mediterranean region.

Hmotová rekonstrukce raně středověkého opevnění a jeho vývoje

Autoři představují rekonstrukční 3D model vývoje raně středověké fortifikace, zachycující postupné proměny opevnění centrální lokality od poslední třetiny 9. století do počátku 12. století. Východiskem rekonstrukce různých konstrukčních typů jsou relikty opevnění centrální části Pražského hradu, zachycené záchranným archeologickým výzkumem v 80.–90. letech 20. století na severní hraně hradčanského ostrohu. Na dvou místech se podařilo dokumentovat kontakt pozůstatků fortifikace s dochovanými dubovými konstrukcemi, z nichž bylo získáno několik dendrochronologických dat.

Dendrochronological data from twelve countries proved definite growth response of black alder (Alnus glutinosa [L.] Gaertn.) to climate courses across its distribution range

Abstract Black alder (Alnus glutinosa [L.] Gaertn.) is an important component of riparian and wetland ecosystems in Europe. However, data on the growth of this significant broadleaved tree species is very limited. Presently, black alder currently suffers from the pathogen Phytophthora and is particularly threatened by climate change. The objective of this study was to focus on the impact of climatic variables (precipitation, temperature, extreme climatic events) on the radial growth of alder across its geographic range during the period 1975–2015. The study of alder stands aged 46–108 years was conducted on 24 research plots in a wide altitude range (85–1015 m) in 12 countries of Europe and Asia. The most significant months affecting alder radial growth were February and March, where air temperatures are more significant than precipitation. Heavy frost and extreme weather fluctuations in the first quarter of the year were the main limiting factors for diameter increment. Within the geographical setting, latitude had a higher effect on radial growth compared to longitude. However, the most important variable concerning growth parameters was altitude. The temperature’s effect on the increment was negative in the lowlands and yet turned to positive with increasing altitude. Moreover, growth sensitivity to precipitation significantly decreased with the increasing age of alder stands. In conclusion, the growth variability of alder and the number of negative pointer years increased with time, which was caused by the ongoing climate change and also a possible drop in the groundwater level. Riparian alder stands well supplied with water are better adapted to climatic extremes compared to plateau and marshy sites.

Dendrochronology improves understanding of the charcoal production history

Charcoal piles have become a frequent subject of research in recent years as a better understanding of past human activities in forests is sought. The age of charcoal piles is usually determined by radiocarbon dating; dendrochronology is rarely used because of the small size of preserved charcoal remains and the insufficient number of visible tree rings. This paper presents the potential for dendrochronological and 14C method in research into charcoal piles. From 14 charcoal-burning sites in the Czech Republic, 214 pieces of charcoal were anatomically identified at the genus level and dendrochronologically analysed. Our results show that fir dominated in these charcoal remains, followed by oak, beech, spruce and pine. With an overall dendrochronological dating success of 24 %, fir charcoal was dated most often (65 %) with measurable tree rings ranging from 14 to 90. The oldest charcoals were dendrochronologically dated to summer 1682 CE; conversely, the youngest had end dates in the second half of the 19th century. The relatively poor dating success of oak charcoal very likely resulted from the use of branches for charcoal production rather than tree trunks. Based on an analysis of selected charcoal samples, we confirm that radiocarbon dating provided a very wide range of dates in the post-1650 CE period and the use of the wiggle-matching method was usually challenging because of short TRW series. Based on samples with preserved waney edges, we conclude that charcoal was more commonly made from wood felled in the summer than in the winter. Despite the relatively low level of success of dendrochronological dating, it seems more effective for dating charcoal than the 14C method, especially with samples from the last 350 years.

Tree-ring chronologies of Picea abies, Larix decidua and Fagus sylvatica along altitudinal gradients

The dendrochronological climate signal of Norway spruce (Picea abies), European larch (Larix decidua), and European beech (Fagus sylvatica), among others, depends on altitude, therefore we have to collect dendrochronological data systematically for each species along altitude gradients. To this end, we established local tree-ring chronologies for the three species along two elevation gradients: (1) Kokra – Jezersko with sites at 750, 780, 950, 1200, 1250, 1380, 1600 m a.s.l., and (2) Bled – Radovna – Krma with sites at 518, 550, 580, 700, 750, 900, 950, 1000, 1200, 1400, 1600, 1760, 1900, 2040 m a.s.l. We present the main characteristics of the chronologies and the results of the dendroclimatological analyses, which show how the climatic factors influence the variation of the tree rings in dependence of altitude and species. We also present the agreement of the different chronologies in terms of standard dendrochronological parameters such as the t-value and discuss the potential use of the presented database.

Post-seismic aggradation history of the West Coast, South Island, Aotearoa/New Zealand; dendrogeomorphological evidence and disaster recovery implications

In the active tectonic setting of Aotearoa/New Zealand, large earthquakes are a relatively frequent occurrence and pose particular threats to infrastructure and society in Westland, on the west coast of South Island. In order to better define the medium- and long-term (annual to decadal) implications of these threats, existing dendrochronological data were supplemented by several hundred tree-ring analyses from 14 hitherto unstudied living tree stands in five catchments; these were combined to compile a regional picture of the location, extent, and timing of major prehistoric reforestation episodes on the floodplains of the area. These episodes correspond well with known dates of large earthquakes in the area (ca. 1400, ca. 1620, 1717 and 1826 AD), and their extents are thus interpreted to reflect the sediment deliveries resulting from coseismic landsliding into mountain valleys, and their reworking by rivers to generate widespread avulsion, aggradation, floodplain inundation and forest death. This regional aggradation picture can underpin anticipation of, and planning for, the medium- to long-term societal impacts of future major West Coast earthquakes. The source location of the next major earthquake in the region is unknown, so any of the Westland floodplains could be affected by extensive, up to metre-scale river aggradation, together with avulsion and flooding, in its aftermath, and these could continue for decades. Re-establishment and maintenance of a functioning economy under these conditions will be challenging because roads, settlements and agriculture are mostly located on the floodplains. The differences in floodplain vegetation between prehistoric and future episodes will affect the rapidity and distribution of aggradation; response and recovery planning will need to consider this, together with the impacts of climate changes on river flows.

Aging mulberry trees (Morus nigra L): The Charterhouse, London, UK

ABSTRACT Black or Common Mulberry (Morus nigra) was introduced into Britain in the late sixteenth – early seventeenth centuries and has since had limited success as an ornamental and fruit-producing tree. Older specimens survive in a limited number of locations including at The Charterhouse in central London. Four of these trees were investigated with the aid of standard dendrochronological techniques, historic images, including an early postcard and a painting by Edward Ardizzone, and with the application of expert knowledge of the forms and ages of contemporary mulberry trees. Results included the creation of a new ring-width chronology (CH_Mulberry) and dating that suggests the two oldest trees may well have been planted to commemorate either Queen Victoria’s Golden (AD 1887) or Diamond Jubilee (AD 1897). The research represents a first known dendrochronological investigation of the species, highlighting issues associated with sampling “tortuous” growth forms and the poor visibility of sapwood rings, as well as the potential for the use of branch ring-widths to facilitate dendrochronological dating of fruit and other trees.

Tree-ring data set for dendroclimatic reconstructions and dendrochronological dating in European Russia

The data set presented represents 15 years of collection. It contains tree-ring width measurements from 64 sites of living trees and ten historical chronologies based on archaeological and construction wood up to year 572 CE, altogether 2909 tree-ring series and more than 450000 measured and cross-dated tree rings. It covers the vast territory of European Russia, including its forested northern and central parts, and the Northern Caucasus mountains. The potential use of these data include climatic reconstructions of regional and hemispheric scale, dendrochronological dating of historical and cultural wood, ecological and remote sensing studies.

Dendrochronological dating and provenance determination of a 19th century whaler in Patagonia (Puerto Madryn, Argentina)

Dendrochronological methods have been widely used to determine the date of construction and provenance of shipwrecks. Despite a large number of shipwrecks, the application of dendroarchaeological techniques is relatively incipient in the coasts of South America. This paper presents the results of a dendroarchaeological study conducted at the shipwreck site "Bahía Galenses" (BG), located in the western sector of Golfo Nuevo, on the Patagonian coast of the South Atlantic Ocean. Based on previous archaeological research, two hypotheses were tested in this study. First, the wreck described in the BG 2 sub-site corresponds to a mid-19th-century whaler built in the northeastern US. Second, these remains correspond to the Dolphin, a northeastern American whaler built in Warren (Rhode Island) in 1850 and shipwrecked in the Atlantic coast of Patagonia in 1859. Using dendroarchaeological provenance methods and a novel approach based on the gridded North American Drought Atlas, we found highly significant correlations between the wreck's tree-ring width series and white oak and yellow pine tree-ring reference chronologies from the eastern US. The latest non-cutting dates obtained in this analysis correspond to the year 1849. To our knowledge, our study pioneered the use of dendrochronological methods for dating and establishing the provenance of a whaler's remains on the Atlantic coast of South America and encourages the feasibility for future dendroarchaeological research based on the large number of wooden shipwrecks that occurred in the region.

Palaeoenvironmental changes and anthropogenic impact recorded in floodplain sediments: A case study from the lower Morava River Basin (Czech Republic)

The Morava River catchment in the Czech Republic serves as sedimentary archive reflecting various natural and man-made processes, and was studied by several authors from the point of view of flood frequency, anthropogenic contamination, or alluvial history. However, more consistent and detailed information on the effect of human activities, namely in terms of land use and river regulation, is missing. The aim of this study is to reconstruct the palaeoenvironmental and anthropogenic processes affecting the floodplain sediments in this area, focusing on the last few hundreds of years. Alluvial sediments from river banks and drilled cores were collected in the Strážnické pomoraví area from sites both inside and outside dams constructed to avoid flooding. Magnetic parameters, reflecting the composition and grain-size distribution of iron oxides, which serve as fingerprints of lithogenic vs. pedogenic vs. anthropogenic origin, are complemented by the radiocarbon and dendrochronological dating. In addition, deposition age was estimated using the 137Cs activity and persistent organic pollutant content. Our results reveal continuous increase of ferrimagnetic minerals (magnetite) input to the floodplain, suggesting increased soil erosion in the catchment. Significantly different pattern was observed inside and outside the flood dykes. The erosion accelerated since the 1950s due to incorrect land use and introduction of modern agriculture techniques. Finally, the industrial pollution significantly contributes to the magnetic enhancement of the topmost 50 cm of the floodplain sequences. Although the results represent local case study, they have more general validity in the sense that records of paleoenvironmental changes and human activities in floodplain sediments may not be well preserved in all the strata, and also their spatial distribution of individual markers may show significant variability.

Radiocarbon dating and Hallstatt chronology: a Bayesian chronological model for the burial sequence at Dietfurt an der Altm\xfchl \u2018Tennisplatz\u2019, Bavaria, Germany

This study is first attempt to refine Early Iron Age absolute chronology, specifically the timing of the Hallstatt C-D transition in southern Germany, using Bayesian chronological modelling of radiocarbon (14C) dates. The Hallstatt period (c.800–450 BC) marks the transition from prehistory to proto-history in Central Europe. The relative chronological framework for Hallstatt burials developed by the mid-twentieth century is still used today, but absolute dating is limited by the scarcity of dendrochronological dates and the perception that 14C dating in the Hallstatt period (HaC-HaD) is futile, due to the calibration plateau between c.750 and 400 cal BC. We present new AMS 14C dates on 16 HaC-HaD burials from a stratified sequence at Dietfurt an der Altmühl ‘Tennisplatz’ (Bavaria, Germany). This sequence is situated entirely on the ‘Hallstatt plateau’, but by combining 14C dating with osteological, stratigraphic, and typological information, we demonstrate that the plateau is no longer the ‘catastrophe’ for archaeological chronology once envisaged. Taking into account dendrochronological dating elsewhere, we show that at Dietfurt, the HaC-HaD transition almost certainly occurred before 650 cal BC, and most likely between 685 and 655 cal BC (68.3% probability), several decades earlier than usually assumed. We confirm the accuracy and robustness of this estimate by sensitivity testing. We suggest that it is now possible, and essential, to exploit the increased precision offered by AMS measurement and the IntCal20 14C calibration curve to re-evaluate absolute chronologies in Early Iron Age Europe and equivalent periods in other regions.

The Integrated Use of Dendrochronological Data and Paleoecological Records From Northwest European Peatlands and Lakes for Understanding Long-Term Ecological and Climatic Changes—A Review

Our overall understanding of long-term climate dynamics is largely based on proxy data generated from archives such as ice cores, ocean sediments, tree rings, speleothems, and corals, whereas reconstructions of long-term changes in vegetation and associated climate during the Holocene are largely based on paleoecological records from peat and lake sequences, primarily pollen and plant macrofossil data. However, since no proxy can provide a complete picture of the past, it is important to integrate different types of data, and to use methods that can support the paleoecological and paleoclimatic interpretations. Here we review how tree-ring data and dendrochronological approaches can be integrated with stratigraphic records to provide complementary paleoecological and paleoclimatic information. The review includes multiproxy studies in which dendrochronological data have been either compared or integrated with stratigraphic records, mainly pollen records, with the aim to contribute to a better understanding of long-term ecosystem and climate dynamics. We mainly focus on studies from northwest Europe in which tree-ring data and at least one type of paleoecological proxy record from the same site or area has been either compared or integrated. We find that integration of dendrochronological data and paleoecological records from peat and lake sequences is a powerful but underutilized approach to reconstruct long-term ecological and climatic changes. One likely reason for its limited use is the contrasting character of the two categories of data, including their different time resolution and occurrence, making them difficult to integrate. For example, subfossil wood providing annual dendrochronological data usually only occurs sporadically in peat and lake sediments, and the presence/absence of the trees are normally expected to be recorded in the pollen data with multi-decadal or coarser resolution. Therefore, we also discuss methods to compare and integrate dendrochronological and stratigraphic records, as well as the relevant paleoecological and paleoclimatic information provided by dendrochronology, pollen, and peat stratigraphy, with the aim to facilitate new multi-proxy initiatives that will contribute to a better understanding of long-term ecosystem and climate dynamics and thereby a firmer basis for future nature conservation initiatives.

The sources of Baltic oak

Past trade in oak from the lands to the east and south of the Baltic Sea was extraordinary in that it dominated the Northern European market for specialized oak products for many centuries. Equally extraordinary is the fact that since the 1980s, when a large corpus of dendrochronological data from artworks was demonstrated to represent the material evidence for this past trade, we, until now, have not been able to pinpoint where, in this large region, the trees for this trade grew. Through our analysis we can now present the likely sources of three major timber groups in this material, and significantly, the new chronologies that we make available here, will be the key foundation for dating and identifying provenance of Baltic oak, for tree-ring research long into the future.

Salix shrub encroachment along a 1000 m elevation gradient triggers a major ecosystem change in the European Alps

Shrub encroachment, a globally recognized response to climate warming, usually involves late successional species in mountain environments, without alteration to climax communities. We show that a major ecosystem change is occurring in the European Alps across a 1000 m elevation gradient, with pioneer hygrophilous Salix shrubs, previously typical of riparian forests, wetlands and avalanche ravines, encroaching into the climax communities of subalpine and alpine belts shrublands and grasslands, as well as snowbeds, pioneer vegetation and barren grounds in the nival belt.We analyzed Salix recruitment through dendrochronological methods, and assessed its relationships with climate and atmospheric CO2 concentration. The dendrochronological data indicated that Salix encroachment commenced in the 1950s (based on the age of the oldest Salix individuals, recruited in 1957), and that it was correlated with increasing atmospheric CO2 concentration, spring warming and snow cover decrease. Hygrophilous Salix shrubs are expanding their distribution both through range filling and upwards migration, likely achieving competitive replacement of species of subalpine and alpine climax communities. They benefit from climate warming and CO2 fertilization and are not sensitive to spring frost damage and soil limitations, being observed across a gradient of soil conditions from loose glacial sediments in recently deglaciated areas (where soils had not had sufficient time to develop) to mature soils such as podzols (when colonizing late successional subalpine shrublands).Salix encroachment may trigger ecosystem and landscape transformations, promoting the development of forests that replace pre‐existing subalpine shrublands, and of open woodlands invading alpine grasslands and snowbeds, making the alpine environment similar to sub‐Arctic and Arctic areas. This results in a new threat to the conservation of the plant species, communities and landscapes typical of the alpine biota, as mountain ranges such as the Alps provide limited opportunities for upward migration and range‐shift.

Wpływ zmian litologii i morfologii dna doliny Mrożycy w Brzezinach na rozwój zabudowy miasta od średniowiecza do współczesności

Wpływ zmian litologii i morfologii dna doliny Mrożycy w Brzezinach na rozwój zabudowy miasta od średniowiecza do współczesności

Znaczenie kalibracji radiowęglowej skali czasu dla chronostratygrafii późnego vistulianu

Znaczenie kalibracji radiowęglowej skali czasu dla chronostratygrafii późnego vistulianu

Картографирование современных процессов в ландшафтах (на примере ООПТ Санкт-Петербурга)

The study of actual processes in landscapes, including their mapping, is based on the idea of an elementary landscape as a unity of a stable component (landscape site) and more dynamic landscape states. Mapping of actual landscape processes is tackled through the example of the territory of the Gladyshevsky Nature Reserve (Karelian Isthmus, St. Petersburg). To study actual processes, materials of the landscapes and vegetation monitoring on the key plots, route studies, dendrochronology data, remote sensing data, forest survey materials, map of landscape sites and actual vegetation map were used. The succession of tree species were indicated by the presence of a young stand and abundant viable undergrowth of the tree species that did not coincide with the predominant stock species, as well as by the tree falls of the predominant species. An increase in the stock of dominant tree species was revealed in areas with a significant stock and relatively young trees (up to 80 years for conifers and up to 50 for deciduous). Reforestation processes are also common on former agricultural lands abandoned in the second half of the XX century. Processes unrelated to the dynamics of stands are represented by paludification and stabilization of mire plant communities, recreational digression and coastal processes. In total, 30 types of actual processes are highlighted on the map, represented by contours, and 2 types of processes indicated by linear signs (accumulation and erosion of the shores of the Gulf of Finland).

ХРОНОЛОГИЧЕСКАЯ ТИПОЛОГИЯ ПАМЯТНИКОВ ДЕРЕВЯННОГО ЗОДЧЕСТВА Г. ЕНИСЕЙСКА

Nowadays in Yeniseysk more than seventy diverse wooden architecture monuments have been preserved. The time of their construction remains debated. On the basis of a comprehensive (dendrochronological, historical and architectural) study, a chronological typology was created, according to which wooden structures (residential buildings, outbuildings and some government buildings) were grouped into four chronological types: I — structures of the first quarter of the 19th century (izbas, five-wall houses on a high utility basement with a hip or pyramidal roof with small windows that retained the features of the Russia’s North tradition); II — structures of the late 1860s — early 1890s (post-fire eclectic two-storey buildings with a glazed gallery on the second floor of the side extension and outbuildings attached to them); III — buildings of the 1890s (government wooden buildings and one-two-storey residential buildings with a glazed gallery on the second floor, which differ from the second type in less expressive design features (cornice platbands, etc.)); IV — buildings of the early 20th century (one-storey buildings with the bright saw-cut decoration of platbands and cornice). A separate group was made up of objects with more archaic features (compared with the obtained dendrochronological dates), which preserved old traditions. The proposed chronological typology made it possible to detail the town-planning processes of Yeniseysk. The methodological arsenal developed in the work is expanding and deepening the research potential of trends in Siberian wooden urban construction study towards the end of the 18th — beginning of the 20th century. The developed methodological approach has a significant research potential for the chronological attribution of Siberian wooden urban construction in the late 18th — early 20th centuries.

Динамика растительности юга Приморья при климатической ритмике малого ледникового периода

Six stages of vegetation development have been identified on the basis of a palynological study of floodplain deposits of the Tsukanovka River (southern Primorye). The first stage is transitional from the medieval warm period, the next four stages are comparable with the climatic phases of the Little Ice Age. The sixth stage in the development of vegetation reflects the modern warming in the 20th century, when modern landscapes have been formed with the participation of the anthropogenic factor. The specific development of a complex of atmospheric-hydrospheric processes, which developed under the direct influence of long-term variations in solar activity, was the reason for the emergence of the Little Ice Age. The coldest phase in the territory of southern Primorye occurred at the end of the 17th century and coincided with the Maunder Grand Minimum of solar activity (1645–1715), it is also characterized by a decrease in humidity. The development of forest vegetation in the valley of the Tsukanovka River recorded alternating warm and cold episodes during the Little Ice Age. In relatively warm phases, the proportion of oak and other broad-leaved trees increased in the forest vegetation in southern Primorye, while in cold phases the proportion of alder increased. In the first half of the XVI century on the territory of southern Primorye, an increase in humidity due to an increase in precipitation is noted. The correlation of paleoclimatic rhythms identified on the basis of spore-pollen analysis results during the Little Ice Age in southern Primorye, with dendrochronological data for the southern Sikhote-Alin and other regions of the northern hemisphere, as well as with historical evidence from neighboring China, has showed the synchronism of the onset of climatic events in the regions, which reflects their global nature and global scale.

Потенциал дендроархеологии в разных природных зонах Западной Сибири

Scientists face with many limitations that affect the success of dendrochronological dating working with archaeological (architectural) sites in Western Siberia. Here we analysed 134 sites and carried out the existing limitations of the method in different natural areas. As a result, a connection between the efficiency of dendrochronological dating and the physical and geographical conditions of sites was found. Created algorithm allowed to assess the potential of dendrochronology for the forest-steppe, taiga and forest-tundra areas of Western Siberia. The scientific results presented in the article can be used to solve the problems of chronology and periodization of archaeological and architectural sites of Western Siberia, as well as to increase the overall efficiency of the application of the dendrochronological method.