Tree-Ring Talk

Human securities, sustainability, and migration in the ancient U.S. Southwest and Mexican Northwest

In the US Southwest and Mexican Northwest, tens of thousands of people were on the move in the 1200s through 1400s CE. By the end of the 1400s, regional-scale population levels had declined by about 50%. What conditions led to this pulse of migration and depopulation? Here we show, through a Southwest/Northwest scale meta-analysis of sub-regional archaeological studies, the spatial distribution, intensity, and variation in social and environmental conditions within eight culture areas, prior to depopulation.

Influence of Viscum album on the growth of Pinus sylvestris in Poland and Central Europe

The growing intensity of climate change combined with increased urbanization is causing a modification of weather patterns in Central Europe, specifically the rising temperature and precipitation distribution and intensity in recent decades. These phenomena adversely affect groundwater levels, indirectly affect forest ecosystems, and contribute to declining in tree health. For example, this affects their susceptibility to external pathogens (i.e. insects, fungi, parasites, etc.) that can lead to tree mortality.

Stable isotopes in tree rings of Pinus heldreichii can indicate climate variability over the eastern Mediterranean region

A long-term context is important for understanding past climatic variability. Although tree-ring widths (TRWs) are widely used as a proxy for reconstructing past climate, the use of annually-resolved values of δ ¹³C and δ ¹⁸O tree-ring stable isotopes (TRSIs) is increasing and may provide further valuable information. Here, we present a 487-year-long TRW chronology and 240-year-long TRSI chronology for Bosnian pine (Pinus heldreichii H. Christ) and compare them to each other.

Widths and stable isotopes of Larix tree rings in a glacier-fed river basin in the Swiss Alps respond to a changing climate

Tree-rings are a valuable proxy for reconstructing past environmental conditions such as climate at annual or intra-annual resolutions. Tree-ring dating combined with stable isotope analysis (e.g. δ ¹⁸O and δ ²H) has an enormous potential for better understanding climate dynamics and for tracing freshwater resource availability under a changing climate.

Direct effects of tephra fallout on Nothofagus pumilio ring widths in northern Patagonia

We evaluated the radial growth response of adult Nothofagus pumilio (Poepp. et Endl) Krasser trees affected by tephra deposition following historical volcanic eruptions of the Puyehue–Cordón Caulle Volcanic Complex (PCCVC) in northern Patagonia. Standard tree–ring width chronologies were developed for trees from two sites that were affected by up to 55 cm of tephra during the 2011 eruption, which allowed us to detect the general tree–growth response to eruptions VEI ≥ 3 and VEI ≤ 2.

Teaching dendroclimatology to our educators and youth

Bryan Yockers and Lee Borzick were invited to participate in the Research Experience for Teachers collaborative research project by the Laboratory of Tree-Ring Research, funded by the National Science Foundation, and led by Irina Panyushkina and Dave Meko.

Upside down and the game of C allocation

Soluble sugars (e.g. glucose, fructose and sucrose) and starch are the most abundant components of the non-structural carbohydrates (NSCs) stored in woody tissues of the stem and roots. These compounds represent the most abundant C reserves in trees, contributing to plants survival and their resilience to adverse conditions. These compounds are involved in controlling and regulating photosynthate allocation between C supply and demand.

How trees can contribute to reconstruct the local pollution history and remove ultrafine particles from the atmosphere

Dendrochemistry has proven to successfully provide a temporal record of trace metal deposition from a variety of pollution sources. Trace element uptake by trees was mainly thought to occur by soil-root transfer but direct transfer of particulate matter from the atmosphere to the shoots is also possible. However, the physiological mechanisms involved in the uptake and transport processes of ultrafine particles is largely unknown. Their presence in the tree rings is still unexplored.

New ¹⁴C dating of Sintashta's largest worship structure—BSK: baffling story of one ziggurat that challenged the narrative of Middle-Late Bronze Age archaeology in the northern Eurasian Steppe.

Research on the sociocultural complexity of the Eurasian steppe in the Bronze Age has been challenged by recent advances in the prehistorical calendar chronology derived from high-precision AMS carbon-14 measurements. The medley of archaeological cultures in the Southern Urals on the border between Russia and Kazakhstan is distinguished in space with the prominent typology of ancient ceramic and burial traditions.

How does Pinus ponderosa water use before and after the North American Monsoon impact the δ¹⁸O measured in wood cellulose in the American southwest?

In the southwestern U.S. the North American Monsoon (NAM) delivers summer precipitation from July – September and the rest is provided as snowmelt in early spring. Both periods serve as an important water source for plants, but due to the heterogeneous nature of the NAM, not all locations within the region receive precipitation, leading to differences in soil moisture.

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