Tree Rings and Climate: Sharpening the Focus.

A brief overview is given of the major contributions of dendroclimatology to current knowledge and understanding of climate variability and change. Particular attention is given to: (1) greatly enhanced information on the spectrum of climate variability, especially on interannual, decadal, and multidecadal timescales; (2) the history of regional to hemispheric temperatures over recent centuries; (3) the probable causes of the variability seen in tree-ring and other records over the past millennium; (4) attempts to determine the quantity `climate sensitivity΄ of the Earth΄s climate system; and (5) reconstructions of the behavior of circulation features and of regional climates, notably drought. Emphasis is given to the importance of regional, continental, and broader-scale networks, as well as to a wide array of technical advances, in making these achievements possible. Then an impressive array of applications is discussed, ranging from ecology and hydrology to anthropology and archaeology. Finally, attention is given to the prospects for dendroclimatology, and in particular to suggestions for making best use of its strengths and for overcoming its weaknesses. [ABSTRACT FROM AUTHOR]