Tree-Ring Talk

A new spatiotemporal field reconstruction of last millennium Northern Hemisphere summer temperatures

Climate field reconstructions allow surface temperature variability to be estimated in both space and time from proxy paleoclimate data, providing targets for general circulation model comparisons and knowledge about the fingerprint of regional-scale climate variability in response to radiative forcing and internal climate system variability. Here, we use a network of 54 temperature-sensitive tree-ring width, density, and blue intensity chronologies at high latitudes to reconstruct the Northern Hemisphere summer temperature field back to 750 CE.

Calculating the flow of energy and water in complex terrain with high performance computing (HPC): Implications for dendroecology and dendroclimatology research.

High Performance Computing (HPC) is freely available to all University of Arizona researchers. However, understanding how to develop HPC applications and workflows that go beyond current desktop computing applications are not necessarily within the purview of most earth scientists. Collaboration between computer scientists and geoscientists is now a necessity to achieve cutting edge performance and results, e.g. in the life sciences the time to sequence DNA genomes are now counted in hours instead of years because of HPC and software developed specifically for research.

How long does a 15 year drought last? On the correlation of rare events

Recent tree ring analyses of the Colorado river flows over the past 500 years enable one to characterize the fluctuations on various timescales using Fourier analysis. We model these flows and calculate the clustering properties of droughts. These results are highly pertinent to the issue of water storage in the Mead and Powell reservoirs and the necessity to rethink how we use water in the southwestern US.

Climatic Changes and Their Effects on Rainfall in Hawai‘i

In the past three decades rainfall has been decreasing over many parts of the Hawaiian Islands, while temperatures have been rising. If these trends continued, severe deficit in the moisture availability could affect many parts of the Hawaiian Islands, with devastating impacts on Hawai‘i’s native ecosystem. In this presentation I will discuss how climate variability on the large-scale and rainfall variability on the small scale are related. Based on these empirical relations, statistical downscaling methods have been developed for the Hawaiian Islands.

Beyond chronology – a tale of tall trees

Barrels, as packaging for a range of traded goods, often ended up re-used in wells and latrines in towns. Tree-ring analysis of barrel finds not only supplies us with a precise chronology for their manufacture, and for the dating of the contexts in which they are found. The region of origin of the wood, through provenance determination, reveals connections between regions that might not necessarily be detected in the other finds from a site. In this talk, I will present some of the most recent provenance determination results that have emerged through my research in Northern Europe.

What I did this summer

The first Tree-Ring Talk of the semester will include multiple short summaries by lab members highlighting what they have been up to over the summer.  The talks will be followed by an informal social to give people the opportunity to catch up with each other.  Presenters will include:

  • Amy Hudson and Soumaya Belmecheri
  • Ben Bellorado
  • Charlotte Pearson
  • Dave Meko
  • Irina Panyushkina
  • Kit O'Connor
  • Paul Szejner
  • Peter Brewer
  • Ramzi Touchan
  • Ross Alexander
  • Valerie Trouet

Dendroarchaeology in Northwestern New Mexico: Results of Presession 2015 Research

Drought-associated tree mortality: Global patterns and insights from tree-ring studies in the Soutwestern U.S.A.

White fir as an invasive species in the Pinaleño Mountains

Proliferation of shade-tolerant species during the period of fire exclusion has been put forth as a major driver of increased severity of fire and insect outbreak regimes in mixed-conifer forests of the interior West.  Both fire regimes and insect defoliator outbreak regimes are responsive to closed and multi-storied canopies.  Douglas-fir tussock moth (Orgyia pseudotsugae) and western spruce budworm (Choristoneura occidentalis), both major pests in interior West forests, are particularly responsive to the presence of white fir (Abies concolor).  However, quantitative studies chara

A Tree-Ring Smorgasbord

A traditional Swedish smörgåsbord contains many dishes, where you usually sample a little of each. In this talk, I will serve a tree-ring based smorgasbord, based on my career as a tree-ring scientist over the last twenty years or so. I will guide you through various environments and research projects across the world, with some special focus on the long-term research conducted in the central Scandinavian Mountains.

Subscribe to Tree-Ring Talk