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Changes in atmospheric circulation, precipitation patterns, and lake hydrology over the last ~12,000 years in Alaska

As a result of rapidly rising temperature in Alaska, glaciers are melting, sea ice is diminishing, lake levels are dropping, and precipitation patterns are changing. These rapid changes are superimposed upon naturally occurring patterns of climate variability in the North Pacific and Arctic Ocean basins, and must be interpreted in the context of these longer-term changes.

Using virtual field experiences (VFEs) for science communication and outreach

Virtual field experiences (VFEs) have become more popular in geoscience and field science education and outreach at both the K-12 and college levels. They are incredibly valuable in allowing students to experience or visualize an environment that they wouldn't be able to visit otherwise, while also providing an opportunity for them to learn about the science that researchers are conducting in that environment. VFEs have been shown to be particularly effective for hard-to-reach and hard-to-imagine field sites, like drilling ice cores on top of Mt.

Tree rings and paleoenvironment on the Southeast Atlantic Coast: insights and developing research

A huge buried deposit of bald cypress trees is providing insights into over 5000 years of paleoenvironmental changes on the Southeast Atlantic Coast. Information from tree rings and chemical analyses, supported by other lines of environmental proxy data, reveals changes in rainfall, sea-level, hurricane frequency, and ecological stability in antiquity. We have initiated complementary analyses to bolster our interpretations.

TBA Tree-Ring Talk (open for volunteeer)

To date,.....

Where did the timber frame come from? A preliminary multi-variable dendroprovenancing study on living oak trees

To date, dendroprovenancing studies have been conducted using almost exclusively tree-ring with (TRW) chronologies. Floating archaeological series are usually crossdated against a network of master chronologies. The highest correlation statistics are used to associate the floating archaeological series to a specific geographic area and to determine the more probable provenance of a wooden artefact. However, this approach shows some limitations (e.g.

Evaluating the abruptness of dendrochronologically-reconstructed western spruce budworm outbreaks

Reconstructed insect regimes provide information on outbreak interval length, periodicity, duration, and associations with climatic patterns. We explored patterns associated with western spruce budworm outbreak initiation, dating “foremost years” as when the percentage of trees recording defoliation reached a prescribed limit, and quantified outbreak abruptness as the number of years between when 25 and 50% of the trees were defoliated. We re-analyzed budworm data from Colorado and New Mexico to demonstrate the utility of these statistics.

Coupling between summer North Atlantic jet variability and European forest productivity and growth

Dynamically-driven extreme weather events have large ecological, social and economic consequences including large tree-growth reductions and forest mortality. These events are likely to become globally more frequent and intense under increased anthropogenic forcing and associated changes in coupled atmosphere-ocean circulation. The jet stream latitude (JSL) over the North Atlantic-European domain provides a synthetic and robust physical framework that integrates climate variability not accounted for by atmospheric circulation patterns.

Arctic Amplification: Do rivers matter? A tree-ring case study of seasonal streamflow changes in the Yenisei River Basin (Russia)

The Yenisei River is the largest contributor of freshwater and energy fluxes among all rivers draining to the Arctic Ocean. We quantify larch tree growth response to river discharge at the upper reaches of the Yenisei River in Tuva, South Siberia. Two regression models built from tree-ring width chronologies are applied to reconstruct winter (Nov–Apr) and annual (Oct–Sept) discharge. This new hydrological archive doubles the length of the instrumental discharge record at the Kyzyl gauge and resets the temporal background of discharge variability back to 1784.

Diversity in dendrochronology

In 2016, only 6% of US Geoscience PhDs went to students from underrepresented minorities, leading Bernard et al. (2018) to conclude that no progress has been made on diversity in 40 years. The situation is similar in the field of dendrochronology. In this talk I will discuss the biases in the publication process, in academic careers, and in various forms of recognition that lead to this lack of progress. I will focus my talk on biases against women scientists, for which the most scientific evidence is available.

Miracle March, August flooding, and October atmospheric rivers: Seasonal wet extremes & the tree-ring record

Moisture-sensitive trees provide exceptional long-term records of streamflow, snowpack, and rain within the context of our changing climate. The delivery of a large portion of annual moisture in a short period of time can present a challenge to our interpretation of these records. This is particularly true in arid and semi-arid regions, where late-spring snowpack, summer convective storms, or autumn atmospheric rivers can provide a high percentage of annual water in a season that might not be aligned with tree growth.

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