Qilian juniper (Shao et al. 2009).
This is one of 15 species of one-seeded junipers having smooth leaf margins, a group very well represented in the eastern portions of the central Asian plateau; based on morphological evidence its closest relative is probably J. komarovii, although a study using randomly amplified polymorphic DNAs (RAPDs) found it to be most similar to J. saltuaria (Adams 2000). Syn: Sabina przewalskii (Kom.) W.C. Cheng et L.K. Fu 1978; Sabina przewalskii f. pendula W.C. Cheng et L.K. Fu 1975 (Farjon 2005).
Monecious trees (rarely shrubs) to 20 m tall. Branchlet systems not tapering and subequal in length throughout system; branchlets loosely arranged, straight or slightly curved, terete or 4-angled, thick, ultimate ones 1.2-1.5 mm diam. Leaves both scalelike and needlelike: all needlelike on young trees, both types on adult trees, nearly all scalelike on old trees; needlelike leaves in whorls of 3, spreading, free part 4-8 mm long; scalelike leaves decussate, usually glaucous, rhombic-ovate, 1.2-3 mm long, usually with cuticular wax; abaxial gland basal, convex; leaf apex acute, free. Pollen cones ovoid, ca. 2.5 mm long with 6-10 microsporophylls, each with 2 or 3 pollen sacs. Seed cones blue-black to black when ripe, ovoid to subglobose, 0.8-1.3 cm diameter, 1-seeded. Seeds slightly flattened, (sub-)globose, 7-12 × 6-10 mm, obscurely or prominently ridged, with resin pits (Fu et al. 1999).
China: Gansu, E Qinghai, N Sichuan (Songpan Xian) (Farjon 2005), where it occurs in forests on mountain slopes at 2600-4300 m elevation (Fu et al. 1999). Hardy to Zone 6 (cold hardiness limit between -23.2°C and -17.8°C) (Bannister and Neuner 2001).
At least three studies have been done. Zhang and Qiu (2007) developed a 1017-year chronology. I don't know if that included wood from dead trees. Peng et al (2008) studied variation in climate-growth response on an elevational gradient. Recently Shao et al. (2009) announced that sampling in the Qaidam Basin of living, dead, and archeological wood from this species have been used to assemble a 3,585-year tree-ring chronology, the longest yet developed in China.
Adams, R.P. 2000. Systematics of the one seeded Juniperus of the eastern hemisphere based on leaf essential oils and random amplified polymorphic DNAs (RAPDs). Biochem. Syst. Ecol. 28: 529-543. Available: http://www.juniperus.org/articles.html (accessed 2008.10.13).
Komarov. 1924. Botaniceskie Materialy Gerbarija Glavnogo Botaniceskogo Sada RSFSR 5: 28.
Peng Jianfeng, Gou Xiaohua, Chen Fahu, Li Jinbao, Liu Puxing, and Zhang Yong. 2008. Altitudinal variability of climate-tree growth relationships along a consistent slope of Anyemaqen Mountains, northeastern Tibetan Plateau. Dendrochronologia 26(2):87-96.
Shao Xuemei, Wang Shuzhi, Zhu Haifeng, Xu Yan, Liang Eryuan, Yin Zhi-Yong, Xu Xinguo, and Xiao Yongming. 2009. A 3585-year ring-width dating chronology of Qilian juniper from the northeastern Qinghai-Tibetan Plateau. IAWA Journal 30(4): 379-394. bio.kuleuven.be/sys/iawa/IAWA%20J%20pdf's/30.no1-4.2009/379-394.pdf, accessed 2010.10.14.
Zhang, Qi-Bin and Hongyan Qiu. 2007. A millennium-long tree-ring chronology of Sabina przewalskii on northeastern Qinghai-Tibetan Plateau. Dendrochronologia 24(2-3): 91-95. ABSTRACT: Long tree-ring records on the Qinghai-Tibetan Plateau (QTP) are important for understanding better the Asian monsoon variability and its linkage with other global climate systems such as El Niño/Southern Oscillation activities. Here we report a 1017-year tree-ring chronology of Sabina przewalskii Kom. from the northeastern QTP. Climate-growth response function and correlation analyses show that radial growth of Sabina trees is positively associated with total precipitation in May and June of the growth year. Multidecadal variation in Delingha tree-ring chronology exhibits similar pattern with those of Dulan and Wulan chronologies of the nearby areas, suggesting that spring precipitation is a major factor limiting the growth of Sabina trees over a large spatial scale. Corresponding to the Little Ice Age, the three chronologies indicate spring droughts during 1440s to mid-1510s, mid-1640s to 1720s, late 1780s to late 1820s, and around mid-1870s. Examination of the tree-ring record in two largest historically documented El Niño events of 1789-93 and 1877-79 reveals that these very strong El Niño events were associated with conditions of spring droughts, and weakening of pre-monsoon circulation may precede occurrence of El Niño in some cases. The relationship between reduced monsoonal precipitation and very strong El Niño activity is, however, much complex and worth further study by spatio-temporal expansion of data coverage in the future.
Adams, R.P., Chu Ge-lin and Zhang Shao-Zhen. 1994. The volatile leaf oils of Juniperus przewalskii Kom. and forma pendula (Cheng & L.K. Fu) R.P. Adams and Chu Ge-lin from China. JEOR 6: 17-20. Available: http://www.juniperus.org/articles.html (accessed 2008.10.13).
Farjon (2005) provides a detailed account, with illustrations.
Last Modified 2012-11-27