Chin J Plan Ecolo ›› 2010, Vol. 34 ›› Issue (6): 628-641.DOI: 10.3773/j.issn.1005-264x.2010.06.002

• Research Articles • Previous Articles     Next Articles

Tree ring reconstruction of summer temperature variations over the past 159 years in Wolong National Natural Reserve, western Sichuan, China

LI Zong-Shan1; LIU Guo-Hua1*; ZHANG Qi-Bing2; HU Chan-Juan1; LUO Shu-Zheng1; LIU Xing-Liang3; and HE Fei3   

  1. 1State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China;
    2State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China;
    3Institute of Ecology, Sichuan Forestry Research Academy, Chengdu 610081, China
  • Received:2010-01-11 Online:2010-06-01 Published:2010-06-01
  • Contact: LIU Guo-Hua

Abstract: Aims Improved understanding of tree growth responses to climate is needed to model and predict forest ecosystem responses to current and future climatic variability. Coniferous forests in Wolong National Natural Reserve occupy broad elevational ranges with varied geology and topography and thus have great potential for dendroclimatological studies. However, little is known about the growth-climate relationships in this region compared with the nearby Tibetan Plateau. Our objective was to determine the main climate responses in diameter growth and examine the regional climate variability within this ecological complex area.
Methods We used standardized dendroecological methods to study the effects of climatic variability on radial growth of a subalpine conifer, Abies faxoniana, which is the dominant and economically most important tree species in this region. We sampled 58 stands of A. faxoniana in a treeline site (3 450 m) and extracted increment cores for radial growth analyses. Several statistics were used to identify common patterns of interannual growth variability, and correlation and regression analyses were used to identify climatic factors associated with that variability.
Important findings The main limiting factor for tree growth was temperature in summer (June to August), followed by temperature in early spring (March), relative humidity from June to September of the current year and precipitation in October of the prior year. The summer (June to August) temperature reconstruction, spanning A.D. 1850–2008, was verified with independent data and accounted for 28.8% of the actual temperature variance during the period in common period (1955–2008). The most obvious characteristic of the reconstructed temperature was a significant warming trend after the 1940s. Before the 1940s, the climate of this region was consistent cold, with cold intervals in the 1850s–1870s and the 1890s–1930s. Because the low-frequency variation of the reconstruction agreed with previously published tree-ring proxies (ice cores of nearby glaciers), it appears that our reconstructed series was reliable and could aid in the evaluation of regional climate signal. Wavelet spectral analysis indicated the existence of some decadal (10–16 years) and interannual (2–8 years) cycles, which probably are ascribed to solar variability and El Niño-Southern Oscillation (ENSO), respectively.