Climatic signal in tree-ring chronologies of Cedrus deodara from Chitral Hindukush Range of Pakistan

Tree-rings are an important tool for the investigation of paleoclimatic records for regions or periods of time with no instrumental climatic data. However, the responses of different species and sites to various climatic parameters are unusual. In the present study, we developed tree-ring-width chronologies of Cedrus deodara from three different sites of Chitral Hindukush range of Pakistan. The study was conducted to understand tree-growth climate relationship and its applicability in proxy climate investigations. The chronologies covered the past 469 to 595 years, with a mean segment length (MSL) ranging from 148 to 223 years. Climatic data obtained from the three weather stations showed strong correlation and was found useful for tree-ring climate relationships. Correlation Function (CF) and Response Function (RF) analysis showed that spring precipitation (March–May) is a critical limiting factor for tree-ring growth, and temperature prior to November may also play a major role in affecting tree ring-growth. The results exposed that the three sites have continuous relationship indicated that only single species from different locations are affected by the same environmental variables and hence can be used in climate reconstruction in combination. The Cedrus deodara chronologies developed at different locations had several corresponding narrow and wide marker rings indicating a large macroclimatic response to regional climatic conditions. The current study suggests that the tree-rings of Cedrus deodara from the Chitral Hindukush range could be used to develop chronologies for the reconstruction of seasonal climatic variables.     

Oak decline in a southern Finnish forest as affected by a drought sequence

We investigated the decline of a pedunculate oak (Quercus robur L.) forest growing on shallow soil at the northern distributional limit of the species in southern Finland, using the dendroclimatic approach. About 200-year-old trees in three vigour classes — healthy, declining and dead — were sampled in 2008. Annual tree-ring, earlywood and latewood widths were measured and chronologies were established. The tree-ring data were correlated with monthly and seasonal climate data. Radial increment of oaks was positively related to the June and July precipitations. This was expressed especially in total ring width and latewood width, whereas the earlywood was more influenced by the warmer winter and spring. Furthermore, the correlation between the current year earlywood width and the preceding year latewood width was higher than between the earlywood and latewood of the same year. The analyses showed that the dead oaks and part of the declining oaks had ceased growing during 2005–2007 after a decadelong summer drought series. This indicates a time lag in the oak dieback. The radial growth of the declining and the dead oaks had dropped already since the 1990s, while the healthy oaks had better longterm growth and higher adaptive capacity to climate variation.     

The application of the tree-ring chronologies in assessing ecological requirements of Metasequoia glyptostroboides growing in southern Poland

Metasequoia glyptostroboides is considered to be a species highly resistant to harmful environmental factors. For this reason it has been introduced to the cities. The climate of Krakow differs from that in its natural range in China. The research was focused on 40-year-old trees, planted in Kraków on fertile alluvial soils with a low level of ground water, in the vicinity of the steelworks. During the period of the highest level of air pollution in the 1970s and 1980s, the radial increment of investigated trees showed an increasing trend. At the end of the 1980s, when the emissions were reduced, a decreasing trend in radial growth was recorded. Throughout the entire period of their life the investi-gated trees have shown high homogeneity of short-term growth reactions. The sensitivity chronology of the trees was characterized by a high representativeness and a strong high-frequency signal. This may indicate that the investigated trees have shown a large sensitivity to climatic factors. The positive effect on the radial growth of Metasequoia had a cold September in the previous year, and also a cold January, April and May in the year of ring formation. Positive impact on the growth of trees had also the high precipitation occurring in April and August, as well as high air humidity in the spring of the year of ring formation. In the period 1974–2011 fifteen signature years were found. The analysis of the climatic conditions in these years confirms the results of the statistical analyses.     

First dendroarchaeological dates of prehistoric contexts in South America: chullpas in the Central Andes

Despite the existence of long-lived tree species with excellent tree-ring characteristics, the use of dendrochronological techniques for dating archaeological contexts has been very limited in South America. Recent research in the Bolivian Altiplano of the Central Andes has yielded a network of Polylepis tarapacana chronologies that goes back to the 13th century. This species was regularly used by local populations since pre-Columbian times as raw material for beams, lintels, hooks and other architectural features in houses, storage chambers, and sepulchers. The aim of this study is to argue in favor of the potential of P. tarapacana for providing high resolution dates of significant archaeological events during the pre-Columbian era. The chronology of chullpas (burial towers and storage chambers) in the southern Andean Altiplano is used as a case study. Growth rings from P. tarapacana have provided several centennial-length dendrochronological records including a reference regional chronology covering the last 786 years in the Central Andean highlands. Based on this long reference chronology calendar years were assigned to woody pieces from pre-Hispanic chullpas. Dendroarchaeological results are consistent with contextual evidence and most radiocarbon dates from woody samples and related archaeological items. Our results indicate that P. tarapacana has a high potential for providing annually-resolved tree-ring dates for archaeological contexts in the Altiplano since the early 13th century.     

A STATISTICAL APPROACH TO THE CALIBRATION OF FLOATING TREE-RING CHRONOLOGIES USING RADIOCARBON DATES

The bristlecone pine tree-ring calibration of radiocarbon dates, while necessitating changes of up to 700 years in Holocene chronology before 1000 b.c. , offers possibilities of very accurate dating when ¹⁴C determinations from floating tree-ring chronologies are utilized. A statistical approach assuming linear regression is developed and used to position the floating tree-ring chronologies at Swiss neolithic sites, using radiocarbon dates published by Ferguson, Huber and Suess and by Suess. The statistical method gives objective estimated dates with estimates of error related, in a consistent and explicit manner, to the inherent inaccuracies of the radiocarbon dates. Most of the method may readily be tested by standard statistical procedures. For the particular cases considered the assumptions of linearity and parallelism are investigated, and the precision of the estimated dates is comparable with that claimed by Suess and his co-workers. A precise calibration is thus possible without utilizing the short-term fluctuations in the Suess calibration curve. The analysis, while avoiding some assumptions of Suess and his collaborators, offers an explicit procedure for establishing controlled teleconnections with the Ferguson dendrochronology, and supports their emphasis on the importance of radiocarbon dates from floating tree-ring sequences for the construction of precise prehistoric chronologies.     

The age of the subfossil trunk horizon in deposits of the Warta River valley (central Poland) based on <Superscript>14</Superscript>C dating

The present study focuses on investigations carried out in the Late Vistulian succession of the Warta River deposits (central Poland) in which a horizon of subfossil trees was excavated. Prelim-inary conclusions on time record and past environmental conditions of a forest existence determined from radiocarbon dating, pollen analyses and geological evidence appear promising with view of tree-ring chronologies.     

Climate influence on radial increment of oak (Quercus SP.) in central Poland

The study investigates the influence of climate conditions on radial increment of oak, with special concern to the situations when analysed trees formed conspicuously wider or narrower tree-rings. The research material was collected in four locations in central Poland within natural range of pedunculate and sessile oaks. The elaborated residual chronologies were correlated with CRUTS 2.1 climate data. The analyses included thermal and pluvial conditions spanning from April of the year prior to ring formation to September of the current growth year. Special interest was paid to simple water ability index that combined both temperature and precipitation during the vegetation season. Additionally, pointer year analysis was carried out to determine situations when conspicuously smaller or larger increment was formed. Investigated chronologies cover the period of 1927?C1992 (?ochów), 1845?C1992 (P?o??sk), 1868?C1992 (Pu?tusk), and 1796?C1992 (Soko?ów). The analysed oaks from sites in central Poland exhibit growth patterns comparable with those known form previous studies concerning that species, where influence of precipitation (higher and positive) and temperature (negative) have been observed. Extreme growth reactions expressed by negative and positive pointer years turned to present high dependence of analysed oak?? growth on water availability during vegetation season.     

Tree-ring chronologies for the 6th to 16th centuries for oaks of southern and eastern England

The background to the problem of providing useful oak chronologies for the variable environmental conditions that apply in southern and eastern England is outlined. The reference chronologies published here embrace three new principles. Firstly, the samples, nearly 300, on which they are based are almost entirely of boards or planks that are of radial section (from oaks aged on average about 250 years) that form part of panel paintings or chests. Secondly, to take account of the differences in the growth pattern with the vigour of growth, separate chronologies for sequences of different ring-width have been formed. Thirdly, on account of the difficulties in extending, with the samples available, an English chronology by the method of overlapping, eight separate chronologies, each about 300 years long, have been created. Matching has been based on German methods, i.e. computer comparisons (with more than one reference chronology) supported by visual comparison of charts. Agreement values in about half a million positions were calculated.These reference chronologies, expressed as ring-widths, are suitable for application to oaks that have grown within a region of considerable size that covers both sides of the North Sea. For panels used as a support for paintings of the 15th and 16th centuries, they have dated 85% of 130 English (London area) ones and about the same percentage of 25 Flemish ones. Rather earlier, sequences for oak boards used in places as far apart as York, Norwich, Oxford and Winchester have been matched. In the 10th to 12th centuries, the ring-width chronology derived for the London area shows good agreement with those for the hilly regions of Germany and that for Schleswig, as well as dating floor planks from Viking houses in York. A floating chronology, 322 years long, dataed to the 6th to 9th centuries by several radiocarbon analyses, has been formed from long sequences of rings from timbers excavated at Old Windsor and Portchester: this has matched material from Southampton and is linked with a mean curve for the well at North Elmham (Norfolk) and the strakes of the Graveney ship.     

A palaeotemperature record for the Finnish Lakeland based on microdensitometric variations in tree rings

X-ray based tree-ring data of maximum latewood densities (MXD) was combined for south-eastern Finland. This data originated from subfossil and modern pine (Pinus sylvestris L.) materials comprising a continuous dendroclimatic record over the past millennium. Calibrating and verifying the MXD chronologies against the instrumental temperature data showed a promising opportunity to reconstruct warm-season (May through September) temperature variability. A new palaeotemperature record correlated statistically significantly with the long instrumental temperature records in the region and adjacent areas since the 1740s. Comparisons with tree-ring based (MXD and tree-ring width) reconstructions from northern Fennoscandia and northern Finland exhibited consistent summer temperature variations through the Medieval Climate Anomaly, Little Ice Age, and the 20^th century warmth. A culmination of the LIA cooling during the early 18^th century appeared consistently with the Maunder Minimum, when the solar activity was drastically reduced. A number of coolest reconstructed events between AD 1407 and 1902 were coeval to years of crop failure and famine as documented in the agro-historical chronicles. Results indicate an encouraging possibility of warm-season temperature reconstructions using middle/south boreal tree-ring archives to detail and enhance the understanding of past interactions between humans, ecosystems and the earth.     

Stone Age midden deposition assessed by bivalve sclerochronology and radiocarbon wiggle-matching of Arctica islandica shell increments

Sclerochronology, the study of the skeletal diaries of mollusks and corals, is a high-resolution geochronological tool of versatile usage in archaeology and paleontology with increasingly growing opportunities. Much of the recent efforts have concentrated on building multi-centennial bivalve growth records using annually deposited increments in the Holocene shells, comparable to tree-ring chronologies. In the context of geoarchaeology, the hitherto unachieved potential includes the application of sclerochronology to reconstruct long-term settlement histories. Here we contribute to both of these critical issues by presenting the first multi-shell sclerochronology constrained by methods originally developed in tree-ring research, using anthropogenically deposited bivalve shells of Arctica islandica excavated from a Stone Age midden in North Norway. Our systematic chronological approach to shell growth histories lays the foundation for a multi-dimensional dating framework that interacts between the incremental, radioisotopic and stratigraphic evidence. We show how the crossdating within and between the single-shell records yields a 155-year multi-shell sclerochronology, supported by the ¹⁴C AMS dates, that demonstrates minimum midden accumulation of 82 years and a depositional rate of 0.3 cm/yr. Sclerochronology paves the way for radiocarbon wiggle-matching, which narrows the probabilistic 2-σ uncertainty range for the oldest and youngest ¹⁴C AMS dates to 3150–2980 and 3060–2890 BC, respectively. We attribute the spectral characteristics of the chronology primarily to the North Atlantic Oscillation, suggesting essentially similar influences of climate variability on the Stone Age culture and our own society.     

Radiocarbon and dendrochronological dating of Sub-fossil oaks from Smarhoń riverine sediments

Sub-fossil oaks from Smarhoń in Belarus have been investigated and tree-ring chronologies were assembled. According to radiocarbon dating, the oldest oak grew from 5782–5612 cal BC and the youngest from 1575–1747 cal AD. Radiocarbon and dendrochronological dating of 97 samples, four single series, 10 mean curves (containing 2–9 series) and three chronologies (10–25 series) were constructed. The longest chronology (No. 16), covering 549 years, was absolutely dated against various oak chronologies of Polish/Baltic origin to AD 778–1326. Germination and dying-off phases were assessed from the three best replicated chronologies. A spectral analysis of the chronologies provided cycles of variable length, on average of 25 years.     

Sub-fossil wood from the Rucianka raised bog (NE Poland) as an indicator of climatic changes in the first millennium BC

The dendrochronological studies were carried out on very well preserved sub-fossil pine wood found in the biogenic deposits of the Rucianka raised bog (NE Poland). Local floating chronologies, covering the period 990-460 cal BC, were dated on the basis of radiocarbon analyses. Growth depressions in annual treering widths indicated periodical deterioration of the environmental conditions, which affected tree growth. Identified germination and dying-off phases (GDO) should be related to the wetter climatic periods. The extinction of trees took place during periods of higher groundwater level which, in turn, caused favourable conditions for growth of young pines.     

Plant remains and amphorae from the Roman harbour under Flacius Street in Pula (Istria,Croatia)

The aim of this archaeobotanical and archaeological research is to expand knowledge about Roman diet and plant cultivation in Istria and to compare it with similar localities on the Eastern Adriatic coast. We have also tried to find some new information about maritime trade routes in the Mediterranean area in ancient times. Out of 27 samples collected from an excavated Roman port in Flacius Street in Pula, in total, 9809 plant macrofossils were recovered, identified and analysed. The results of the analysis show that most of the plant remains belong to the group of fruit trees and nuts. The most abundant are the remains of Ficus carica, Pinus pinea, Vitis vinifera subsp. vinifera, Rubus fruticosus agg. and Olea europaea subsp. europaea. These are all species that are widespread in the Mediterranean area and have likely always been consumed by the local population. The number of ruderal and weed species found is relatively high (31) in comparison with other plant categories (fruit trees and nuts; fruit collected from the wild; cereals; condiments; oil crops; vegetables and tubers; plants of fresh water environments; elements of maquis), but as they came to the site accidentally and not by targeted human activity, there are far fewer macrofossils of such plants than those of cultivated species. There were a few elements of evergreen forest vegetation and plants of aquatic habitats at the site (2 + 1), which suggests the existence of this type of vegetation in the area of the site in Roman times. Archaeobotanical comparisons of the site in Flacius Street with similar coastal Roman sites—Verige Bay on Veli Brijuni (first-fifth century ad), the port of Zaton near Nin (first-third century ad) and Caska Bay on the island of Pag (first and second century ad)—reveal considerable similarities, confirming the uniformity in nutrition and plant growth in the wider coastal area. Together with the two Roman ships, during the archaeological excavations of the Roman harbour and its layers, we collected over 2000 different archaeological artefacts out of which a large number was almost perfectly preserved. Some of the mentioned artefacts include ceramic amphorae, ceramic table- and kitchenware, ceramic lamps, different usable objects made of glass, wooden use objects, parts of ship’s equipment and other wooden tools, architecture elements from the nearby port as well as residential structures and remains of stone monuments. Because of the large amount of artefacts found at the site, the analysis of the artefacts and data processing are still in progress. As a contribution for recognizing organic remains, we isolated the amphorae whose purpose was the storage and maritime transportation of different food products and ingredients.     

Provenancing Baltic timber from art historical objects: success and limitations

During the Middle Ages northern Belgium and The Netherlands were gradually deforested. A steadily rising demand for quality timber obliged merchants to look for new timber sources. From the 13th century onwards, large volumes of timber were imported from surrounding regions and, despite the remote supply area, merchants of the Hanseatic League managed to organize a huge timber trade from towns around the Baltic Sea.Trees from forests along the Vistula River seem to have been exported via Gdansk, first to Bruges and later to Antwerp. At their final destination the imported wood assortments were highly appreciated for shipbuilding and construction purposes, but also by woodcarvers and famous painters.Over the last decade dendrochronologists have established a dense network of historical site chronologies for northern and central Poland. These site chronologies are supposed to reflect local growth conditions and may allow the identification of the provenance of the wood of many art historical objects made out of Baltic timber.Tree-ring patterns of panel paintings and sculptures, mainly from the 14th–16th centuries, were measured and compared to this data set of site chronologies. An evaluation of the accuracy of sourcing medieval Baltic timbers using standard correlation techniques was made. The identification of provenance enriches historical information on logging activity and timber trade around the Baltic Sea during the Middle Ages.     

Growth responses of sessile oak to climate and hydrological regime in the Zbytka Nature Reserve, Czech Republic

Complex of Nature reservation Zbytka is the rest of various fen vegetation in the northeast part of the Czech Republic. It represents an important spring area which provides high quality potable water for more than 150 000 inhabitants. Waterworks utilization was started in the 1960s and the change of land-use practices has had a strong effect on the ecosystem. Oak chronology has been showing different tree growth trends since the start of the waterworks utilization. Also the occurrences of negative pointer years differ markedly before and after initiation of pumping underground water. Dendroclimatological analyses primarily revealed a close relationship between the temperature and tree growth ?? positive influence of spring and summer temperature. The period 1983?C1992 of maximum artesian water pumping is expressed as higher tree-ring increments, but linear model analyses showed that the growth reaction of oak is not due to simple causality between temperature and under-ground water level. The radial increments reacted positively to the combination of high temperature during the vegetation season and low or, the contrary, high depth of underground water level. No direct relationship was detected between tree growth and fluctuation of underground water level; despite of the results dendrochronological data may be useful in historical ground water modelling studies. Results are also crucial for conflict of interests between nature preservation and potable water supply.     

Isotopic analysis of the ecology of herbivores and carnivores from the Middle Pleistocene deposits of the Sierra De Atapuerca,northern Spain

Carbon and oxygen isotope values reveal resource partitioning among the large mammal fauna from three contemporaneous Middle Pleistocene hominid-bearing localities within the Sierra de Atapuerca (northern Spain). Carbon isotope values sampled from the tooth enamel of fauna present during Atapuerca Faunal Unit 6 show that a C₃-dominated ecosystem surrounded the area where fossils were preserved during this time. For the herbivores, Fallow deer isotope values are significantly different from Red deer and horses and show that this species did not forage in open environments at this locality. Red deer and horses show similar feeding strategies with less negative carbon values implying use of more open environments for these taxa. For the carnivores, carbon isotope values for Ursus deningeri are significantly different from either lions (Panthera leo) or foxes (Vulpes vulpes) and support the contention that this species is herbivorous. Special metabolic mechanisms involved in hibernation in U. deningeri might also have influenced its isotope values. The carbon isotope values of remaining carnivores were similar and suggest that each was typically a generalist carnivore, eating a wide variety of prey items. While the isotopic results generally correspond to ecology indicated by previous techniques, this study shows that isotope analyses can provide further insights that alternate techniques do not provide. Isotope analyses can help elucidate the ancient ecology of taxa present in the Sierra de Atapuerca during the Middle Pleistocene allowing for an accurate portrayal of the setting in which humans lived.     

FURTHER STATISTICAL METHODS FOR THE CALIBRATION OF FLOATING TREE-RING CHRONOLOGIES

This paper describes the application of some further statistical methods for the calibration of floating treering chronologies to data pertaining to the Neolithic settlement at Auvernier. The more general statistical approach utilizes the information contained in the successive time-derivatives as well as the absolute values of the bristlecone pine calibration curve, by fitting polynomial or piecewise polynomial curves, thereby producing better estimates, in general, of the absolute dates of the floating chronologies. Presentation of results in terms of joint confidence regions enables the relevant stratigraphic evidence to be included in the analysis by simple graphical means. In addition, the paper offers a new approach, using only floating tree-ring chronologies, to the testing of Libby's principle of simultaneity.     

The Dendroecological Potential of Eucalyptus Camaldulensis Dehnhardt (River Red Gum) from the Barmah Forest,Victoria, Australia

The study of tree rings has been used for over 100 years to inform climatic and geomorphological reconstructions. In mainland Australia, no tree species are currently recognised as providing reliable sources for such studies over extensive areas. Eucalyptus camaldulensis is a widely growing species with a growth pattern that is closely linked to high levels of available moisture, such as that associated with floods. The species therefore has the potential to provide palaeoclimatic information that may be of use in hydrological and geomorphological studies. This study initially examines the microstructure of samples of E. camaldulensis taken from the Barmah Forest to assess the applicability of the species to dendroecological investigation. It is found that samples of the species exhibit ring‐like structures, although there are areas of the samples that contain zones of growth without clear ring boundaries. The patterns of growth rings and zones are found to be common to many trees at a site, although the level of variability of pattern from tree to tree is high. Options for future development of the approach described here are to combine ring studies with isotopic‐based analysis to provide a combination of tree age and climatic history.     

Locating the origins of wood resources: a review of dendroprovenancing

Dendroprovenancing studies have been shown to have historically been initiated on the use of oak in art-historical contexts, but are now employed on a much wider range of species and artefact types, particularly in relation to ship remains. The commonest methodology is to compare individual site chronologies with a network of other chronologies, and to recognise trends in the geographical distribution of strong matches, suggesting the likely source area of the material. Other studies may look at the matching of individual timbers to draw similar conclusions. It is shown that ecological and genetic factors may strongly influence individual matching results and that ring-widths may therefore be considered a somewhat crude means of provenancing. Additional chemical and genetic markers are discussed, although these are unlikely to become routinely used in the near future.     

Tree-ring based temperature reconstruction for the west Qinling Mountains (China): linkages to the High Asia,solar activity and Pacific-Atlantic Ocean

We developed a Faxon fir (Abies faxoniana) tree-ring width chronology at the timberline in the western Qinling Mountains, China. Herein February–July mean temperature was reconstructed for Zhouqu in the western Qinling Mountains back to AD 1650 based on the standard chronology. The climate/tree-growth model accounts for 43.5% of the instrumental temperature variance during the period 1972–2006. Spatial correlation analyses with the gridded temperature data shows that the temperature reconstruction captures regional climatic variations over central and southeast China, and strong teleconnections with the nearby High Asia. There is a good agreement with cold and warm periods previously estimated from tree-rings in Nepal, India and southwest China. The temperature re-construction indicates that there was pronounced cooling in Zhouqu during the Maunder Minimum (late 1600s to early 1700s). The cold period (1813–1827) of the temperature reconstruction coincide with the volcanic eruptions. Significant spectral peaks are found at 56.9, 22.3, 11.4, 2.9, 2.8, 2.6, 2.2 and 2.0 years. The spatial correlation patterns between our temperature reconstruction and SSTs of the Atlantic and Pacific Oceans suggest a connection between regional temperature variations and the atmospheric circulations. It is thus revealed that the chronology has enough potential to reconstruct the climatic variability further into the past.