Tree-Ring Lab

During 2011, dendrochronological and botanical analyses of wood remains began at Jaffa in collaboration with the Jaffa Cultural Heritage Project (JCHP).  The aims of this ongoing project, which is part of broader dendrochronological research in the Levant by the authors, are to: 1) use tree-ring dating to provide a precise chronological framework for building activity in Jaffa; 2) use dendrochronology and wood species identification to determine the area from which timbers were obtained (dendroprovenancing); and 3) work with the JCHP to synthesize research results into a database that can be distributed to a greater audience.  Timbers have been examined from three sites in Jaffa: the kishle complex, the French School, and Tel Yafo.  The kishle complex and French School are both recently excavated Late Ottoman buildings.  A 319-year cedar (Cedrus libani) chronology (final ring dating to 1811) was built from the kishle samples, and a 130-year cedar chronology (final ring dating to 1856) was built from the French School samples.  The chronologies correlate extremely well with one another and with modern forest chronologies from western Turkey, indicating that Turkey (not Lebanon) was the timber source.  The Jaffa cedars also have significant correlation with historical timbers from Crete, Rhodes, and Turkey, indicating that Ottoman Jaffa was part of a widespread overland and maritime timber trading network.  Identification of cedar charcoal from the Late Bronze Age gate complex at Tel Yafo gives evidence of even earlier long-distance timber importation and offers potential for high-precision dendrochronological dates at the site.

Dendrochronological research in North-Central Europe and the East Mediterranean has produced networks of long regional oak (Quercus sp.) reference chronologies that have been instrumental in dating, provenancing, and paleoclimate research applications. However, until now these two important tree-ring networks have not been successfully linked. Oak forests and historical/archaeological sites in southeastern Europe provide the key for linking the North-Central European and East Mediterranean tree-ring networks, but previous dendrochronological research in this region has been largely absent. This article presents the initial results of a project, in which we have built oak tree-ring chronologies from forest sites and historical/archaeological sites along a north-south transect between Poland and northwestern Turkey, with the aim of linking the North-Central European and East Mediterranean tree-ring networks and creating a new pan-European oak data set for dendrochronological dating and paleoclimatic reconstruction. Correlation among tree-ring chronologies and the spatial distribution of their teleconnections are evaluated. The southeastern European chronologies provide a solid bridge between both major European dendrochronological networks. The results indicate that a dense network of chronologies is the key for bridging spatial and temporal gaps in tree-ring records. Dendrochronological sampling should be intensively continued in southeastern Europe because resources for building long oak chronologies in the region are rapidly disappearing.

Geomagnetic models based on direct observations since the 1830s show that the averaged relative change in field intensity on Earth's surface over the past 170 years is less than 4.8% per decade. It is unknown if these rates represent the typical behavior of secular variations due to insufficient temporal resolution of archaeomagnetic records from earlier periods. To address this question we investigate two ancient slag mounds in Cyprus - Skouriotissa Vouppes (SU1, 4th - 5th centuries CE, 21 meter in height), and Mitsero Kokkinoyia (MK1, 7th - 5th BCE, 8 meter in height). The mounds are multi-layered sequences of slag and charcoals that accumulated near ancient copper production sites. We modeled the age-height relation of the mounds using radiocarbon dates, and estimated paleointensities using Thellier-type IZZI experiments with additional anisotropy, cooling rate, and non-linear TRM assessments. To screen out ambiguous paleointensity interpretations we applied strict selection criteria at the specimen/sample levels. To ensure objectivity, consistency, and robust error estimation we employed an automatic interpretation technique and put the data available in the MagIC database. The analyses yielded two independent sub-century scale paleointensity time series. The MK1 data indicate relatively stable field at the time the mound accumulated. In contrast, the SU1 data demonstrate changes that are comparable in magnitude to the fastest changes inferred from geomagnetic models. We suggest that fast changes observed in the published archaeomagnetic data from the Levant are driven by two longitudinally-paired regions, the Middle East and South Africa, that show unusual activity in geomagnetic models.

Geomagnetic models based on direct observations since the 1830s show that the averaged relative change in field intensity on Earth's surface over the past 170 years is less than 4.8% per decade. It is unknown if these rates represent the typical behavior of secular variations due to insufficient temporal resolution of archaeomagnetic records from earlier periods. To address this question, we investigate two ancient slag mounds in Cyprus—Skouriotissa Vouppes (SU1, fourth to fifth centuries CE, 21 m in height), and Mitsero Kokkinoyia (MK1, seventh to fifth centuries BCE, 8 m in height). The mounds are multilayered sequences of slag and charcoals that accumulated near ancient copper production sites. We modeled the age‐height relation of the mounds using radiocarbon dates, and estimated paleointensities using Thellier‐type IZZI experiments with additional anisotropy, cooling rate, and nonlinear TRM assessments. To screen out ambiguous paleointensity interpretations, we applied strict selection criteria at the specimen/sample levels. To ensure objectivity, consistency, and robust error estimation, we employed an automatic interpretation technique and put the data available in the MagIC database. The analyses yielded two independent subcentury‐scale paleointensity time series. The MK1 data indicate relatively stable field at the time the mound accumulated. In contrast, the SU1 data demonstrate changes that are comparable in magnitude to the fastest changes inferred from geomagnetic models. We suggest that fast changes observed in the published archaeomagnetic data from the Levant are driven by two longitudinally paired regions, the Middle East and South Africa, that show unusual activity in geomagnetic models.

500 years of ancient Near Eastern history from the earlier second millennium BCE, including such pivotal figures as Hammurabi of Babylon, Šamši-Adad I (who conquered Aššur) and Zimrilim of Mari, has long floated in calendar time subject to rival chronological schemes up to 150+ years apart. Texts preserved on clay tablets provide much information, including some astronomical references, but despite 100+ years of scholarly effort, chronological resolution has proved impossible. Documents linked with specific Assyrian officials and rulers have been found and associated with archaeological wood samples at Kültepe and Acemhöyük in Turkey, and offer the potential to resolve this long-running problem. Here we show that previous work using tree-ring dating to place these timbers in absolute time has fundamental problems with key dendrochronological crossdates due to small sample numbers in overlapping years and insufficient critical assessment. To address, we have integrated secure dendrochronological sequences directly with radiocarbon (14C) measurements to achieve tightly resolved absolute (calendar) chronological associations and identify the secure links of this tree-ring chronology with the archaeological-historical evidence. The revised tree-ring-sequenced 14C time-series for Kültepe and Acemhöyük is compatible only with the so-called Middle Chronology and not with the rival High, Low or New Chronologies. This finding provides a robust resolution to a century of uncertainty in Mesopotamian chronology and scholarship, and a secure basis for construction of a coherent timeframe and history across the Near East and East Mediterranean in the earlier second millennium BCE. Our re-dating also affects an unusual tree-ring growth anomaly in wood from Porsuk, Turkey, previously tentatively associated with the Minoan eruption of the Santorini volcano. This tree-ring growth anomaly is now directly dated ~1681–1673 BCE (68.2% highest posterior density range), ~20 years earlier than previous assessments, indicating that it likely has no association with the subsequent Santorini volcanic eruption.

This article presents new radiocarbon evidence from the Middle Bronze Age palatial site of Tel Kabri (Israel). The final phase of the palace (Phase III) can be dated to Middle Bronze Age II, with an end date around the transition from Middle Bronze II to III or very early in Middle Bronze III. According to our 14C data, the end of Tel Kabri Phase III (and thus the transition from Middle Bronze II to III) can be dated to ~1700 BC. This date is about 50–100 yr earlier than traditional chronological models for the Middle Bronze Age propose (~1650 BC according to the traditional chronology or ~1600 BC according to the low chronology). 14C data from Tel Kabri thus add additional evidence for a higher Middle Bronze Age chronology for the Levant, consistent with recent 14C evidence from Tell el-Dabca (Egypt), Tel Ifshar (Israel), and Tell el-Burak (Lebanon).

The island of Cyprus was well-known in antiquity for its substantial forests and timber resources.  Dendrochronological (tree-ring dating) analysis offers the opportunity to study the timing and origin of timber exploitation with almost unmatched precision, and provides a biological archive of past climate and environment.  Yet, despite multiple studies on modern trees and forest ecology in Cyprus, almost no dendrochronological research has been conducted on the island’s numerous historical and archaeological wood materials.  In response the Cornell Tree-Ring Laboratory has initiated the sampling and analysis of wood from multiple historical and archaeological sites on Cyprus, including a series of villages abandoned during Cypriot Greek-Turkish inter-communal strife and resettlement during the 1960s-70s.  An important aspect of this research includes determining the source of timbers using dendrochronological methods (‘dendroprovenancing’), in order to gain further information on long-term use of trees from different ecological zones and of local or imported forest resources.  We concentrate here on the results of dendrochronological study of two historical villages, Ayios Sozomenos and Phinikas, which show an increase of building activity in the late 19th century-early 20th century, using local pine timber resources, and subsequent repairs to buildings throughout the 20th century, which eventually favored imported northern European timber.  Ongoing work in interviewing former village inhabitants and detailed mapping and image analysis of the buildings allow further important insights into the recent, largely forgotten history of these settlements prior to their mid-20th century abandonment, as well as the environmental history of Cyprus.