Tree-Ring Talk

Mekong River flow reconstructed from tree rings


The Mekong River is an important transboundary water resource for a large part of southeast Asia. Here, we reconstruct the flow of the Mekong River in its upper and lower basin over the last three centuries using tree-ring chronologies from southeast Asia. Apparently extreme low flow events, like those that occurred in 2010, are not exceptional over the length of the reconstruction. Flow varies on interannual to decadal time scales and shows a recent increase in the lower basin, both of which have implications for future sustainable development in the watershed.

A Tree-Ring Based Reconstruction of Balkan Temperatures Back to Medieval Times Reveals a Robust Pan-European Summer Teleconnection Mode

             The dominant atmospheric circulation pattern that governs European summer climate is a seesaw between the geopotential height fields over northwestern versus southeastern Europe: when a low occurs over the British Isles, a blocking-like pattern dominates the Balkans, and vice versa.  One phase of this seesaw was exemplified by the summer of 2012, when anomalously wet and cold conditions over northwestern Europe co-occurred with dry and hot conditions over souteastern Europe.             We here present a summer temperature reconstruction (1274-2009 CE) for the

Can dendrochronology solve the Santorini/Thera question? State of the art AD2012

Since 19th century, the date of the Minoan eruption of volcano Thera in the Southern Aegean Sea has been one of the most challenging historical questions in Aegean archaeology. This catastrophic event became the most important time-marker for East-Mediterranean civilizations. Recent application of the scientific dating methods generated new data, but confrontation with robust historical chronologies based on kings lists, documents, astronomic observations, etc., revealed weaknesses of radiocarbon and ice-core analysis.

Qualitative and Quantitative Variability of Tropical Tree Rings: Implications for Tropical Dendrochronology

Tropical tree species, like their temperate counterparts, show well defined rings, but the high diversity of tropical woody species is reflected in a high diversity of growth-zone structures, formed as a composition of different vessel, fiber and parenchyma characteristics.  Numerous examples show that even trees with generally distinct tree-ring boundaries are subject to high variability within a species and among individuals.

Cedar of Lebanon (Made in Anatolia): Dendroprovenancing Timbers in the Late Ottoman Port of Jaffa

The Anatolian cedar forests were an important source of timber for the Ottoman Empire, particularly in timber-starved provinces like Palestine and Egypt.  I present here results from a study using dendrochronology to date and provenance cedar timbers from two 19th century Ottoman buildings in the Palestinian port of Jaffa.  These results, combined with information from the historical record and dendrochronological data from other Ottoman sites in the eastern Mediterranean, demonstrate that these cedars were imported from Anatolia and were part of a far-reaching maritime and overland trade n

What We Did this Summer

A rather informal, multi-person “what-I-did-this-summer” brown-bag. A chance for Tree-Ring Lab people to reconnect, welcome new colleagues, and learn about the fascinating things that happen in our research worlds.

Calibrating Time Lags in Archaeological Tree-Ring Dating: the Colorado Old Wood Project, Phase I: Douglas Creek Arch and the Uncompahgre Plateau

Archaeologists have long been aware of the potential for serious overestimation of site ages based on radiocarbon and tree-ring dates from certain archaeological contexts. The “old wood problem” arises from the human use of deadwood elements for various purposes and the fact that trees are long-lived plants whose rings date to the years in which they were grown rather than to the years in which the organisms died. Despite a fairly unfocused concern with this issue, little effort has been devoted to quantifying the magnitude of the problem.

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