I have focused on contributing to the building of large scale (continental to global) networks of “proxy” climate records with defined chronology, temporal resolution and climate signal. In support of this general aim I work to:
- establish new kinds of tree ring record (new species, new regions, new variables) that may be used, in combination with other records, to “thencast” the behavior of the climate system. Recently I have mainly cooperated Drs. Matthew Salzer (LTRR), Andy Bunn (Western Washington University) and Kurt Kipfmueller (University of Minnesota and other colleagues on the expansion, enhancement and updating of millennial and multimillennial chronologies of bristlecone pine and its congeners. I continue to work on hemispheric and global climate reconstructions.
- use climate reconstructions or “thencasts” to raise questions about the behavior of the climate system. These questions not only apply to the nature of the 20th century in comparison to earlier periods, but also to the potential existence of multimillennial “regimes” at the scale of the Pacific Basin and perhaps on even larger scales.
- base this on improved understanding of the mechanisms controlling tree-ring variability, primarily in collaboration with Academician Eugene Vaganov of the Russian Academy of Sciences, Dr. Michael Evans (University of Maryland) and Dr. Kevin Anchukaitis (Columbia University). The prime focus of our collaboration has been the further development and testing of a model of the environmental control of tree-ring formation. A separate model for the simulation of tree-ring chronology building and the detection of time-dependent biases in tree-ring chronologies is under development with Dr. Kurt Kipfmueller of the University of Minnesota.
- explore the uses of tree rings along with remotely-sensed data to place recent fluctuations or changes in forest growth in a multidecadal to centennial time perspective.