We developed a network of tree-ring width chronologies of larch (Larix sibirica Led.) from upper tree-lines of the southeast Altai Mountains, South Siberia. Annual tree-ring variability of chronologies since A.D. 1710 was compared using factor analysis. The factor analysis clustered eight tree-ring chronologies into two groups that were used for compositing chronologies. One resulting composite chronology (A.D. 1582-1994) averaged sites from upper tree-lines in glacier-free areas and another chronology (A.D. 1090-1999) captured the sites at upper tree-lines in valleys of the Korumdu, Aktru, Yan-Karasu and Kizil-Tash Glaciers (North-Chuya Range). There is no significant difference in the estimated strength of temperature signals (June and July) of the composite chronologies. However, we observed a remarkable contrast in the decadal variability of larch growth between upper tree-lines of glacier-free areas and glacier valleys. The tree-ring growth of larch was coherent among the chronologies for the period A.D. 1582-1725. Suddenly, low-frequency similarity declined around A.D. 1730. The magnitude of differences became more pronounced after A.D. 1775 indicating three periods with opposite growth tendency (1775-1850, 1900-1915 and 1960-1994) that alternated with short periods of coherent growth. We assume that the low-frequency signal in the glacier valley larch chronology accommodates oscillations of both summer temperature and glacier dynamics. The periods of low-frequency departures are consistent with the 19th Century advance and tremendous 20th Century retreat of the glaciers. We argue that expanded glaciers enhance harmful impacts of katabatic wind on larch growth. It appears that employing tree rings from upper tree-lines of glaciated areas for estimation of decadal and centennial variability climatic proxies should be selected with great caution.

We present a tree-ring based reconstruction of water-year (October–September) streamflow for the Manasi River in the northern Tien Shan mountains in northwestern China. We developed eight Tien Shan spruce (Picea schrenkiana Fisch. et Mey.) chronologies for this purpose, which showed a common climatic signal. The hydroclimatic forcing driving tree growth variability affected streamflow with a three- to four-year lag. The model used to estimate streamflow is based on the average of three chronologies and reflects the autoregressive structure of the streamflow time series. The model explains 51% of variance in the instrumental data and allowed us to reconstruct streamflow for the period 1629–2000. This preliminary reconstruction could serve as a basis for providing a longer context for evaluating the recent (1995–2000) increasing trends in Manasi River streamflow and enables the detection of sustained periods of drought and flood, which are particularly challenging for managing water systems. Several of the reconstructed extended dry (wet) periods of the Manasi River correspond to reconstructed periods of drought (flood) in Central Asia in general and in other Tien Shan mountain locations in particular, suggesting that the analysis of Tien Shan spruce could contribute significantly to the development of regionally explicit streamflow reconstructions.

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / The development of tree-ring chronology for bristlecone pine (Pinus aristata), stretching over 8,200 years, has been used to calibrate the radiocarbon time scale. An extensive deposit of driftwood in Stanton's cave in the grand canyon was estimated to have been deposited on the cave floor about 12,000 years ago on the basis of the 4,095-year radiocarbon age of a split-twig figurine on the surface of the cave floor. However, the initial driftwood specimen gave the surprising C-14 age of 35,000 years. A tree-ring dating study was therefore undertaken on driftwood in the grand canyon in order to: (1) evaluate the driftwood deposit in Stanton's cave; (2) provide a basis for interpreting c-14 dates from canyon archaeological sites; and (3) document a technique for deriving some concept of pre-dam hydrology, especially maximum high water levels. The percentage of dated specimens found indicated that the approach was feasible. A likely interpretation of the seemingly early c-14 dates at archaeological sites is that prehistoric man used old driftwood, as does modern man in the canyon. Tree-ring dates from wood above the pre-dam high water mark indicate that maximum 100-year flood evidence can be obtained.