Tree-Ring Talk

A multimillennial snow water equivalent reconstruction from giant sequoia tree rings

The first dendroclimatic reconstruction of May 1 Snow Water Equivalent (SWE) was developed from a Sequoiadendron giganteum regional tree-ring chronology network of 23 sites in central California for the period 90-2012 CE. The reconstruction is based on a significant relationship between May 1 SWE and tree-ring growth and shows climate variability from inter-annual to inter-centennial time scales. A regression-based reconstruction equation explains up to 55% of the variance of SWE for 1940-2012.

Forests, climate, and tree rings: forecasting the future state of complex systems

At this stage in the Anthropocene, answering questions about the future state of ecological systems has become critical – the future growth of trees exposed to changing climate, tree species’ future geographic distributions, and the future role of forests in the global carbon cycle – yet ecological systems are complex. Summarizing four lines of research, I will illustrate how the use of tree-ring and forest inventory data can help address questions about and improve prediction of forest and climate system dynamics.

From trees to ecosystems: linking remote sensing and dendrochronology in the highest elevation forests in Mexico

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Volcano and pine tree.
Arian Correa

What I did this summer

Our traditional "what I did this summer" lightning talks by students and faculty of LTRR; you are welcome to take 1-5 minutes to say a few words and share one or more slides related to work or fun.

Progress report on reanalysis of the Hawley-Bell collection: Tree-ring chronology building and 14C dating at the religious and political centers of pre-contact eastern North America

During the twelfth century A.D. Indigenous societies across the Mississippi River Basin transformed: populations aggregated into towns around dramatic monumental constructions that represented the seat of polities, communities adopted foreign styles, and more centralized leadership roles emerged. While the general outline of Mississippian history is known, exactly how people came to abandon old cultural practices in favor of the Mississippian pattern is not understood, nor are the historical details of individual mound centers.

The Missouri River: A Story of Two Basins

The Missouri River is unusual because of its two main source regions, one in the high headwaters and one close to the mouth of the river.  In this talk, I report the results of research which explored the hydroclimatology of the basin to better understand the climatic controls on the two parts of the basin, the contribution of the snowmelt-driven streamflow to total Missouri River flow, and the nature of droughts in the instrumental record.  I will also discuss the first comprehensive set of streamflow reconstructions for the upper Missouri River, and the Turn-of-the-21st Century

High-resolution field reconstructions of Mediterranean hydroclimate during the last millennium

The Mediterranean region is projected to experience severe drying trends and more extreme hydroclimate events as a consequence of anthropogenic climate change over the next century.   In some places, this signal may have already emerged from natural variability.  Here we provide content for recent and future changes using new high-resolution spatial reconstructions of multiple hydroclimate fields from a tree-ring network that spans the last millennium.

Back To The Future With Tree-Ring Standardization: Maybe Schulman Did It The Right Way

This talk reflects over 45 years of research and contemplation by me on the tree-ring standardization problem. There is no optimal solution to this problem because the statistical properties of the raw ring-width data we typically process are very complicated and their expressions of radial growth over time are totally unobserved. It has recently become apparent to me that we spend too much time letting the computer do the standardization for us without taking time to look at the data.

Connecting tributary erosion to downstream floodplain forest establishment in a large river network

Sediment eroded from the headwaters of a large basin strongly influences channels and ecosystems far downstream, but the connection is difficult to trace. Disturbance dependent riparian trees are thought to rely upon floods for creation of the sand bars necessary for establishment, but pulses of sediment should also promote formation of this habitat.

Living with the star: Carbon-14 excursions in tree rings as the evidence for extreme solar activity

The annual 14C data in tree rings is an outstanding proxy for uncovering extreme solar energetic particle events (SEP, also called SPE -solar particle event) in the past. Signatures of extreme SEP events have been reported in 774/775CE, 992/993 CE, and ~660 BCE.

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