CR 47:207-218 (2011)  -  DOI: https://doi.org/10.3354/cr01012

ABSTRACT: The tree-ring chronologies of Abies georgei Orr were developed for 3 sites at different elevations: the southern (2750 m), middle (3050 m), and northern (3400 m) parts of the Baimang Snow Mountains in northwestern Yunnan Province, China. The climate-growth response analysis indicated that trees at different elevations respond differently to environmental changes. The radial growth of trees found at the middle and high elevation sites was determined by temperature variables (mean, maximum, and minimum temperatures), particularly during the summer season (June to August), while moisture availability (precipitation and relative humidity) during spring (in March) was the crucial climate factor for tree growth at the low elevation site. The linear climate-growth model derived from the composite chronology of the 2 high elevation sites was verified with independent data from 1958 to 2005, and accounted for 33.4% of the mean temperature variation during summer (June to August). Based on this model, summer minimum temperature variations were reconstructed for the past 296 yr. The reconstruction revealed that cool climates mainly occurred in 1732–1743, 1758–1780, 1791–1824, 1836–1847, 1853–1862, 1908–1929, 1964–1976, and 1979–1993, while warm climates prevailed in 1718–1731, 1744–1756, 1781–1790, 1825–1835, 1883–1907, 1930–1963, and 1995 to present. Spectral analysis of the reconstruction using the multi-taper method (MTM) indicated the existence of some multidecadal (about 70 yr) and bidecadal (about 20 yr) cycles, which might correspond to the related cycles of solar activity, and significant peaks at about 2 to 8 yr, in agreement with the spectral mode of El Niño Southern Oscillation (ENSO)-type variability.

KEY WORDS: Summer temperature · Climate reconstruction · Tree-ring · Northwestern Yunnan