A dendrochronological analysis of Pinus pinea L. on the Italian mid-Tyrrhenian coast

In order to assess the response of the radial growth of Pinus pinea L. to climatic variability in Central Italy, dendrochronological and dendroclimatological analyses were carried out on five different populations scattered along the Tyrrhenian coasts of the peninsula. The aim of this study is to contribute to the understanding of the ecological demands of this species, particularly in the study area. For each site total ring, early-, and late-wood width chronologies were developed. Multidimensional analyses were performed for the three tree-ring datasets in order to analyze the relations between sites chronologies. Both Principal Component Analyses and hierarchical classifications highlighted an important difference of one site in respect to the other, probably due to site characteristics. Correlation functions were performed to infer the main climatic factors controlling the radial growth of the species. For a comparative study, we limited our attention to the common interval 1926–2003 (78 years) in which the response of the tree-ring chronologies to climate at both local and regional scale was investigated. Positive moisture balance in the late spring-summer period of the year of growth is the climatic driver of P. pinea radial growth in the study area. Moreover, this study shows how low summer temperatures strongly favor the radial growth of the species.     

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.     

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.     

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.     

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.     

Shifts Along a Spectrum: A Longitudinal Study of the Western Eurasian Realized Climate Niche

ABSTRACT

Climate niches that modern humans and earlier hominin ancestors occupied have changed dramatically over time, but the extent of those changes has gone largely undocumented. This study investigates the manner in which the realised hominin climate niche has expanded, contracted, or stayed stationary across four time periods (Last Interglacial, Last Glacial Maximum, Mid-Holocene, and 1950–2000) in Western Eurasia. Using spatially gridded general circulation model data and site locations this study examines climate variables from archaeological sites and current Western Eurasian cities to describe both the regional Western Eurasian fundamental and realised climate niches. Changes between the three prehistoric periods and modern-day time period are analysed by calculating each realised niche breadth, overlap, position, and variance. Results indicate that as global temperatures cooled from the Last Interglacial to Last Glacial Maximum, populations expanded their climate niche breadth beyond that of earlier Neanderthal groups, shifting toward regions with less seasonal variation. Conversely, Mid-Holocene humans, who saw the proliferation of both agriculture and population, contracted their realised climate niche space. The contraction and expansion of realised climate niche space illustrates how hominins have evolved the capacity to shift their niche through changes to their subsistence strategy and adaptations to overall climatic conditions.     

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.     

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.     

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.     

Dendroarchaeology of the mid-first millennium AD in Constantinople

The 1st millennium AD was a time of great transition in Europe and the Mediterranean. At the heart of the Byzantine Empire, Constantinople (modern day Istanbul) was a pivotal trade hub for the Aegean region. Establishing a precise and accurate dating framework for the development of this remarkable city and a chronological reference for this critical time period for the Mediterranean region is of great importance to a wide range of scholars. Here we present a new 213 year tree-ring record from 89 oak samples placed in time by dendrochronology and supported by radiocarbon analysis and historical documentation. It represents the middle of the first millennium AD in Constantinople. The tree-ring series are derived from pilings recovered from the extraordinary excavations of the so-called “Theodosian harbor” at Yenikap?, Istanbul, along with timbers from other sites and buildings around the city, including one of the most famous sites on the Istanbul sky-line—Hagia Sophia. They provide potential for new insight into a time period in which earthquakes, the Justinianic plague, and even a possible tsunami struck the city, and during which dramatic changes in climate have been recorded in other paleoenvironmental proxies. The chronology is the first published tree-ring series from the Aegean region to cover the ‘event’ years of AD 536–7 and 542 which are characterized by anomalous growth in other tree-ring series from around the world, but interestingly these event years are not evident in this tree-ring sequence.     

Muslim village intellectuals: The life of the mind in northern Pakistan

The findings reported in this article would not have been possible without the help and support of many people in Chitral. Fieldwork in Chitral was conducted with the generous support of the Master and Fellows of Trinity College, Cambridge, an ESRC research studentship, and a grant from the British Academy Society for South Asian Studies. It has also benefited from sustained and insightful criticism from Dr Susan Bayly, and from four anonymous AT reviewers. Pseudonyms are used for places and people throughout the text.

• 1. 

  I first lived Chitral as a school-leaver in 1995 and made three subsequent visits before conducting a 20-month period of 'formal' anthropological fieldwork in the region between April 2000 and October 2001. This period of fieldwork was followed up by three further shorter stays.

       
  
  

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.     

白洋淀地区史前环境考古初步研究

作为典型的冲积低平原与浅湖沼地貌形态的白洋淀地区,是研究全新世环境变迁及古环境与古文化相互关系的重要地域。全新世气候的变化,不仅影响着白洋淀地区的自然环境,同时也影响着史前人类的生存模式。多年来该区域考古发现的资料证实,全新世气候暖湿与冷干的交替变化,直接影响到遗址分布的数量和所处的地貌位置,亦即影响到人类对居住点的选择,与此同时也影响着史前文化的经济生活类型。     

Bronze Age upland settlement decline in southwest England: testing the climate change hypothesis

The division of land on Dartmoor during the Bronze Age by the construction of moor-wide boundaries known as reaves represents a significant development in agricultural practice and land tenure. Previous research relating to the Dartmoor reaves suggests this way of life may have continued for no longer than 200–400 years. It has been suggested that their abandonment occurred as the result of a deteriorating climate, although there are no published palaeoclimatic reconstructions from the area. We therefore test the hypothesis that on Dartmoor, a marked climatic deterioration occurred in the late Bronze Age that can be linked to the abandonment of the reaves. A palaeoclimatic reconstruction derived from testate amoebae and peat humification analyses is presented from Tor Royal Bog, central Dartmoor, the first such record from southwest England. A major shift to a cooler and/or wetter climate is inferred from ca. 1395 to 1155 cal BC that is coincident with the period hypothesised as encompassing the abandonment. This climatic deterioration is replicated in sites in northern Britain, suggesting it was a widespread event. It is concluded that while the evidence supports a climatically forced retreat, there are a range of other socio-economic factors that must also be taken into consideration.     

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.     

Fluvial sediments, correlations and palaeoenvironmental reconstruction: The development of robust radiocarbon chronologies

Multiple sequences of radiocarbon dates extracted from organic materials are increasingly being used to provide robust chronologies for landscape development, particularly the timing and correlation of significant climatic and ‘process’ events. Whilst the validity of using such frameworks in sedimentary environments such as lake basins and raised bogs has been the focus of much attention, such debates have not extended to fluvial systems. Using examples from three lowland, vertically accreting river valleys in East Anglia, UK, this paper assesses the robustness of their associated radiocarbon chronologies by assessing the contrasting age estimates that are obtained by dating different parts of the same organic sample (humic, humin and plant macrofossils) at a variety of stratigraphic levels. Overall, the humin and humic acid fraction results were statistically consistent, whilst the plant macrofossil remains were found to be of a slightly younger age. In these examples, it is argued that the younger ages appear to be the result of Phragmites (common reed) roots pushing plant macrossils through the sedimentary sequence or opening up voids for material to fall through, although studies in lacustrine and mire environments suggest alternative explanations may also be possible. Whichever explanation is preferred, this study demonstrates clearly that the complexity of valley floor stratigraphy and processes is such, that using single radiocarbon dates, whether AMS or bulk samples to reconstruct chronologies of ‘geomorphic system response’ may need to be refined and subjected to the same level of assessment that has been applied in other sedimentary systems.     

Oaks,tree-rings and wooden cultural heritage: a review of the main characteristics and applications of oak dendrochronology in Europe

We overview the recent development of oak dendrochronology in Europe related to archaeology and art-history. Tree-ring series of European oaks (Quercus robur and Q. petraea) have provided a reliable framework for chronometric dating and reconstruction of past climate and environment. To date, long oak chronologies cover almost the entire Holocene, up to 8480 BC and the network over the entire area in which the two oaks grow is being improved. We present the main characteristics of oak ring series and discuss the latest methodological advances in defining the calendar year in which the tree-rings were formed and in interpreting such dating in terms of the age of a wooden object. Dendrochronology has established itself as a standard dating tool and has been applied in a wide variety of (pre-)historical studies. Archaeological wood, historical buildings, works of art (such as panel paintings and sculptures) have been successfully investigated. Recent advances in dendro-provenancing have helped to obtain more information on the timber trade in the past. Information on past forest structures, silviculture and timber use have become available through scrutinizing historical and contemporary ring-width patterns.     

Explaining prehistoric variation in the abundance of large prey: A zooarchaeological analysis of deer and rabbit hunting along the Pecho Coast of Central California

Three main hypotheses are commonly employed to explain diachronic variation in the relative abundance of remains of large terrestrial herbivores: (1) large prey populations decline as a function of anthropogenic overexploitation; (2) large prey tends to increase as a result of increasing social payoffs; and (3) proportions of large terrestrial prey are dependent on stochastic fluctuations in climate. This paper tests predictions derived from these three hypotheses through a zooarchaeological analysis of eleven temporal components from three sites on central California’s Pecho Coast. Specifically, we examine the trade-offs between hunting rabbits (Sylvilagus spp.) and deer (Odocoileus hemionus) using models derived from human behavioral ecology. The results show that foragers exploited a robust population of deer throughout most of the Holocene, only doing otherwise during periods associated with climatic trends unfavorable to larger herbivores. The most recent component (Late Prehistoric/Contact era) shows modest evidence of localized resource depression and perhaps greater social benefits from hunting larger prey; we suggest that these final changes resulted from the introduction of bow and arrow technology. Overall, results suggest that along central California’s Pecho Coast, density independent factors described as climatically-mediated prey choice best predict changes in the relative abundance of large terrestrial herbivores through the Holocene.     

Neolithic Hedgehogs (Erinaceus europaeus) from the Island of Gotland show early contacts with the Swedish mainland

Previous research probing early migrations and contacts in the Baltic Sea area is characterized by the analysis of different chronologies and subsistent strategies on all sides of the Sea. Several studies performed on artifact typology, ceramics, grave rituals and physical anthropology ended with varying results. Although the question of human origins remains inconclusive, in this study, we rely on the phylogeography of an animal associated with humans to elucidate findings regarding prehistoric human migration and contacts.Hedgehogs, along with other fauna on Gotland, were brought over to the island by humans. We examined hedgehog mitochondrial DNA from the Pitted Ware Culture (Middle Neolithic). The genetic signatures of the animals on the island were investigated to determine the animal’s origin.From the 23 bones originally examined, twelve bones from all five locations studied yielded reliable results and resembled published extant Erinaceus europaeus sequences from Sweden, Norway and Denmark. We postulate that a western heritage for the Neolithic hedgehogs on Gotland indicates early human contact with the Swedish mainland.