Dean The National Science Foundation will continue its long term support of the University of Arizona Laboratory of Tree-Ring Research. This grant allows the laboratory to hire a full-time dendrochronologist to analyze archaeological samples and also provides support for student assistants. The technique of tree-ring dating was pioneered at Arizona. because the rate of tree growth is determined by environmental conditions, yearly growth rings in a tree vary in form and thickness. It is possible to build up a tree ring chronology by cross matching trees from the present to well back in the prehistoric past and then to use this "master record" to date small wood samples collected from archaeological and other situations. For archaeologists in the Southwestern United States, this technique has been a boon because it allows materials to be dated within one year. This far exceeds the accuracy of radiocarbon dating. Because it has not been adequately supported and because many archaeologists lack the funds to pay for its services, the Arizona laboratory has not been able on its own to keep pace with archaeological requests for sample dating. This project will help to remedy that situation. In particular, it will benefit young scientists and those not associated with main line research institutions.