Dr. Steven W. Leavitt has been a professor in the Laboratory of Tree-Ring Research at the University of Arizona since 1990. His undergraduate degree is in geology, and his graduate degrees are in environmental science and geoscience geochemistry) Dr. Leavitt’s research centers on past, present and future global change, variously using light stable-isotope analysis of tree rings, native plant leaves, croplants, soils and geological materials. Leavitt has used carbon isotope analysis in multiple FACE Free-Air CO2 Enrichment) experiments conducted at the Maricopa Agricultural Center Arizona) including cotton, wheat and sorghum, to understand more about impact of CO2 fertilization on croproduction and soil organic carbon pools. He has further pursued use of carbon isotopes in tree rings to investigate environmental moisture, drought, and water-use efficiency of pinyon pine, ponderosa pine and Douglas-fir trees in networks of sites around the US Southwest and Baja. Much of Leavitt’s recent efforts have involved ongoing investigation of wood from ancient buried forests from around the Great Lakes areaning the period from about 4,000 to 15,000 years ago, for tree-ring and isotope analysis to better understand the environment of that time. Additionally, several recent and ongoing studies have involved investigation of tree rings and tree-ring isotopes in China with respect to climate and ecological questions.