Summer temperature variability, Drought and the Atlas Cedar: A tree-ring δ 13C based multi centennial record in Northwestern Africa.
This
project aims to study the water/carbon balance of long-lived Atlas
cedar trees in northwestern Africa to identify conditions that trigger
mass mortality in response to drought. We use annually resolved stable
isotope measurements, wood anatomy and leaf morphological variability to
document physiological stress responses in this species and to
reconstruct summer temperature variability over the last 300 years.
These data will then be used to estimate the future probability of increased mortality using climate projections.
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Estimating forest productivity over regional and multi-decadal time scales using carbon isotopes in tree rings
In this project, we investigate the spatial and temporal dynamics of forest water-carbon exchange in Northeastern U.S. To this end, we use tree-rings δ13C measured from a network of 10 forests focusing on one tree species: Tsuga canadensis (eastern hemlock). We aim at documenting the climate drivers of forest productivity and tree's physiological response to change in climate and increase in atmospheric CO2. We will be able to compare our derived carbon/water exchange documented in tree rings to direct measurements from Eddy-covariance flux towers in 3 forests: Harvard, Bartlett, and Howland.
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Paleoclimate, Paleoenvironment and Other Potential Drivers of Extinction of Mammuthus primigenius, St. Paul Island, Pribilof Islands, Alaska
This is an interdisciplinary project studying a sedimentary record from Lake Hill in order to determine the timing of extinction of mammoths on St. Paul Island- Alaska in the mid-Holocene, as well as the potential drivers of this extinction event. This project involves many different and novel proxies including aDNA, pollen, plant macrofossils, diatoms, cladocerans, chironomids, geochemistry and sedimentation.
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Influence of interannual North Pacific Jet variability on Sierra Nevada Fire regimes
Here we develop a seasonal Jet-Stream climatology across the N. Hemisphere based on the 20 th Century re-analysis data. We specifically propose to develop a tree-ring based reconstruction of winter North Pacific Jet variability-that drive hydroclimate variability over the American Pacific Coast over the last 400+ years. We will then compare this reconstruction to existing, independent paleo-records of CA wildfire activity.
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