This paper describes variability in trends of annual tree growth at several locations in the high latitudes of Eurasia, providing a wide regional comparison over a 2000-year period. The study focuses on the nature of local and widespread tree-growth responses to recent warming seen in instrumental observations, available in northern regions for periods ranging from decades to a century. Instrumental temperature data demonstrate differences in seasonal scale of Eurasian warming and the complexity and spatial diversity of tree-growing-season trends in recent decades. A set of long tree-ring chronologies provides empirical evidence of association between inter-annual tree growth and local, primarily summer, temperature variability at each location. These data show no evidence of a recent breakdown in this association as has been found at other high-latitude Northern Hemisphere locations. Using Kendall's concordance, we quantify the time-dependent relationship between growth trends of the long chronologies as a group. This provides strong evidence that the extent of recent widespread warming across northwest Eurasia, with respect to 100-to 200-year trends, is unprecedented in the last 2000 years. An equivalent analysis of simulated temperatures using the HadCM3 model fails to show a similar increase in concordance expected as a consequence of anthropogenic forcing.

Abstract. Regional tree ring chronology with extension 2209 years (from 212 B.C. till 1996 A.D.) was built for east Taymir and Putoran according to wood of living trees, well-preserved remains of dead trees, and subfossil wood from alluvial bank deposits by the cross-dating method. In addition, the "floating" tree ring width chronology for the period of Holocene optimum (3300-2600 B.C.) was built with extention 685 years and supported by several radiocarbon dates. High values of synchrony and correlation of individual tree ring series show a prevailing effect of one external factor on radial tree growth change in the studied region of the Siberian subarctic. It was established that the main factors of growth variability are the early summer and annual temperature, which explain up to 70% of tree growth rate variability. Cyclic components stable for two millennia were revealed at analysis of the tree ring chronology: double secular (N180 years), secular (78-90 years), and intrasecular (44, 28, 11, and 6.7-6.9 years) variations. Models for reconstruction of the early summer and annual air temperature were obtained according to tree ring variability. Temperature dynamics in the eastern part of Taymir for the last two millenia agree well with temperature variations in the Northern Hemisphere obtained according to other indirect sources. The warming of the middle of the twentieth century is not extraordinary. The warming at the end of the first and beginning of the second millennia ("Medieval Warm Period") was longer in time and closer in amplitude.

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