9314024 Graybill There is widespread agreement on the scientific importance of developing long, high resolution proxy records of climatic and environmental variation in several recent assessments of directions needed for global change research. Tree-ring chronologies are consistently referenced as one of the more important resources that might be used for those purposes. The great majority of chronologies are however limited in temporal coverage to the last 300-400 years. This award supports a workshop devoted to the development of millennial aged tree-ring chronologies that will provide new possibilities for investigating relatively long-term climatic and environmental changes, i.e. during the past 2000-8000 years. This kind of time depth will permit new information for various regions on changes in the level as well as the variance of climatic variables such as temperature and precipitation. The relative frequency of rapid or extreme climatic change events can also be better estimated than was previously possible. The full potential of these long chronologies is not yet known. These are new questions that have arisen and must be considered before that potential can be realized. One of these concerns the most appropriate fashion for constructing long series from overlapping chronology segments in order to preserve the 'true' variance structure of growth-driving environmental variables. Other concern whether the growth response to climate has been constant over time, and if not, is this in turn related to natural changes in stand structure or composition, to anthropogenic activity, or to other factors yet unknown?
