Journal of Geographical Sciences ›› 2007, Vol. 17 ›› Issue (2): 175-186.doi: 10.1007/s11442-007-0175-x

• Climate and Environmental Change • Previous Articles     Next Articles

Standardization of Qilian Juniper ring-width series in the eastern margin of the Qaidam Basin

XU Yan1, SHAO Xuemei1,2   

  1. 1. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China|
    2. Institute of Tibetan Plateau Research, CAS, Beijing 100085, China
  • Received:2006-01-16 Revised:2006-03-05 Online:2007-06-25 Published:2010-09-18
  • Supported by:

    National Natural Science Foundation of China, No.40371118; National Natural Science Foundation of China,No.90502009

Abstract:

Standardization is one of the important procedures in dendroclimatology. We used abundant Qilian juniper (Sabina przewalskii Kom.) tree-ring samples from the eastern margin of the Qaidam Basin to develop a new standardization method, i.e. total growth curve (TGC). The samples that contained the complete pith and reached to the growing culmination around the 40th–60th year were used to fit TGC, and the generalized negative exponential function was used to fit the curve. Usually, most cores cannot reach the arboreal pith for some reasons and it is difficult to determine the arboreal cambial age. The empirical model of initial radial growth (IRG) was employed to estimate the number of rings missing from the pith by the same data and IRG model explained 90.9% of the variance. When developing the chronology, the cambial ages of cores that contained the complete pith were regarded as beginning from the first year and others were determined by the numbers of missing and included rings in the core. Standardization was accomplished by dividing each tree-ring series by corresponding TGC. The chronologies developed by TGC can retain more low-frequency variational infor-mation and TGC helps to develop more reliable tree-ring width chronology.

Key words: the Qaidam Basin, Qilian juniper, tree-ring width, growth trend