Tree-Ring Talk

Present and Future dendrochronological research in Lebanon.

The presentation will be an overview of Lebanon topography, climate, and forest types. It will discuss the different biop-climatic zones and forest types and species found in these zones. The forest products, services, and decline it will also be discussed. Finally, the presentation will focus on past, present, and future dendrochronological research in Lebanon.

The Role of Invasive Earthworms as Ecosystem Engineers and the Associated Implications for Tree-Ring Research in the Great Lakes Region of North America

European earthworms have only recently been recognized as an invasive threat to the hardwood forests of the Great Lakes Region of North America, yet mounting evidence indicates that the invasion of earthworms into forests that had been earthworm-free since at least the last glacial maximum is profoundly and fundamentally altering nutrient cycling, soil structure, and the forest floor communities of these ecosystems. Less attention has been given to how earthworm invasions influence tree growth and productivity.

Climate and Community Assembly in Central Appalachian Forests

The speaker is using dendrochronology to build species-specific growth models that describe how climate influences tree growth in a region where competition for light tends to dominate regeneration and community assembly dynamics.

A continental-scale approach to understanding climate-sensitivity in Douglas-fir

Douglas-fir is the most widespread commerical conifer species in the US and occurs across almost all mountain ranges in the western US.  I have built a network of chronologies across the US range of Douglas-fir to (1) identify where the species is water-limited versus energy-limited, and (2) understand the spatial and temporal dynamics of any quantifiable differences in limiting factors.

POSTPONED: Expanded Fire History for the Chiricahua Mountains

An expanded network of tree-ring sites is used to create an updated and extended fire history for the Chiricahua Mountains of southeastern Arizona.

Snow cover monitoring — challenges and possibilities

There is an undisputed need to increase accuracy of snow cover estimation in regions of complex terrain, especially in areas dependent on winter snow accumulation for a substantial portion of their water supply, such as the Western United States, Central Asia, and the Andes.

Biometric and eddy-covariance based estimates of above-ground carbon uptake

We compare above-ground carbon uptake at five eddy-covariance forest stations in Europe derived from tree-rings and CO₂ fluxes which show highest agreement at seasonal timescales. Carbon uptake rates between 65 and 225 g C m² y⁻¹ could be partitioned into volume increase (Jan–Jun) and cell-wall thickening and storage (Jul–Sep).

A Paleo-Perspective on Precipitation Seasonality from Central Idaho Tree Rings

Douglas fir and limber pine tree rings were collected from lower forest border sites across central Idaho. Sub-annual tree-ring chronologies were used to independently reconstruct seasonal precipitation over the past six centuries. Singular spectrum analysis indicates that annual and summer through winter precipitation exhibits significant decadal and multidecadal variability, whereas spring precipitation shows energetic behavior only at interdecadal timescales.  

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

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