An important goal of the U. S. Global Change Program is to quantify the natural rate and range of variability i the climate system. One of the principal sources of paleoclimatic data with annual resolution comes from the analysis of tree ring thickness. From these data it is possible to reconstruct records of past temperature and precipitation for at least the last few centuries, and perhaps up for the last millennium. This renewal proposal, by an established tree-ring laboratory, requests support to continue the production and analysis of paleoclimatic data derived from tree rings. The goal of the project is to quantify the thickness variations in tree rings; relate the variations in thickness to ecological and climatological parameters; develop long-term records of annual variation in climate; and attempt to isolate anthropogenic effects from natural variations in climate. This research is important because it well help to isolate natural variability in the climate system from the effects of fossil fuel burning by man.
