Tree ring records provide one of the most important data bases for reconstructing past climate variability on time scales of years to decades. This project will merge 900 published and new tree ring records in a grid covering all regions of the continental United States and compare them with the historical records of climate from each cell of the grid. The relationship between drought occurrence and tree ring growth will be determined and used for climate reconstructions back through the historical record to perhaps the 17th century. The importance of this project is that it will reconstruct both the spatial and temporal variability of climate, particularly drought occurrence, in North America during the past three centuries. It will provide the information needed to evaluate the background variability of climate change. This collaborative project includes investigators from the University of Arizona, the University of Arkansas, and the Lamont-Doherty Geological Observatory of Columbia University.
