Dendrochronology is the most exact archaeological dating method available to scholars interested in the recent past. Tree-rings are accurate at the annual, and often seasonal, level of resolution and many other dating techniques are calibrated using tree-rings. Such resolution is critical when assessing hypotheses of human/environment interaction, settlement and subsistence change. Societal benefits of this project include increasing our understanding of long-term human adaptation to sociocultural and environmental variability and from knowledge of past environmental variability, both of which are important for developing environmental and social policy. The Laboratory of Tree-Ring Research (LTRR) at the University of Arizona is the only institution active in all aspects of dendrochronological research. A major component of the Laboratory's research program is the analysis and dating of wood and charcoal from prehistoric and historic archaeological contexts. Thus, the LTRR has become the leading processor of archaeological tree-ring materials, the primary source of tree-ring dates in multiple regions of the world, and the largest repository of archaeological tree-ring samples in the world. The integration of the dating program into the full range of dendrochronological research, teaching, and outreach activities at the Laboratory creates a unique interdisciplinary context that maximizes the scientific value of archaeological tree-ring samples and chronologies, and provides a variety of publics to enjoy the research. The project's primary contribution to archaeological research involves exact dating and chronology building, topics crucial to understanding human behavior, human-environment interactions, and processes of sociocultural stability, variation, change, and evolution. The project contributes to understanding past human activities that remain outside written history, either because they occurred prior to written records or were in areas that were not recorded. Using traditional and new innovative techniques, the project offers stakeholders a long-erm perspective in which to understand past human land and resource use. The findings of the project are almost immediately integrated into University of Arizona classes including an Undergraduate General Education Tier II science course for nonscience majors and undergraduate/graduate courses in the School of Anthropology and departments of Geosciences and Renewable Natural Resources. The project directly contributes to PhD dissertation and MA thesis research by students at the University of Arizona, Northern Arizona University, Washington State University, and other colleges and universities. The project contributes directly to extensive outreach activities that have reached more than 12000 people in the last year, including K-12 programs, graduate and undergraduate students, visiting scholars from around the world, and field training for government, private, and Native American cultural resource management programs. The project engages in cooperative research and training with many US and International universities, government agencies, and private consulting firms. The LTRR tree-ring sample collections and data archives are unparalleled, easily accessed resources for archaeological, historical, and environmental research. Project results are distributed to the public through lectures, newspapers, radio, television, and the internet.. Project personnel have contributed directly to formulating policy for documenting, sampling, and protecting cultural and natural resources by federal, state, local, and tribal land management agencies. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.