Landscape of Qilian juniper at 3800 to 4150 m elevation, in the mountains north of Dulan; trees are on average 500 years old, with the oldest yet identified being 1045 years [Eryuan Liang 2016].
Images of trees in habitat, published as Figure 2 in Wang et al. (2019).
Good line drawing available online via Fu et al. (1999).
Juniperus przewalskii
Qilian juniper; 祁连圆柏 qilian yuanbai [Chinese].
This is one of the central Asian turbinate-cone junipers, a taxonomically complex group subdivided mainly on the basis of molecular studies that have almost all been performed by R. P. Adams and coworkers; the principal such studies were by Adams and Schwarzbach (2012, 2013); see the cladogram of Juniperus for a summary of relationships in the group. J. przewalskii is sister to J. carinata, in a clade sister to J. komarovii, J. convallium, and J. pingii.
Synonyms: 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).
Gene-flow work comparing J. tibetica with three closely-related other junipers of the Qinghai-Tibetan Plateau, J. convallium, J. saltuaria and J. przewalskii, has given us a glimpse of the complex evolutionary history of the turbinate-cone juniper clade, finding evidence of "both incomplete lineage sorting and gene flow after species divergence" (Li et al. 2011; see this source for considerable further insights regarding this group).
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). See García Esteban et al. (2004) for a detailed characterization of the wood anatomy.
This species keys out as very similar to J. komarovii, a neighboring species occupying similar habitats, but the foliage of J. przewalskii has a covering of cuticular wax (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).
Although a 2010 assessment by the IUCN listed this species as "least concern," the dendroclimatic studies below suggest it is quite vulnerable to drought, with most populations living near the limits of tree growth under a semiarid climate (Wang et al. 2019). Global warming and drying, which are forecast in modeling of the northeast Tibetan plateau, could lead to significant population declines.
Wang et al. (2019), reporting a dendrochronological study, identify their oldest trees as being up to 1,100 years old, and their study included 48 trees in the 901 to 1,100-year-old age class, indicating that there are appreciable numbers of extremely old trees. Their study area included the mountains north and northeast of the Qaidam Basin in Qinghai, mostly in the Bayan Shan and Ngola Nanshan. Liu et al. (2019) report a specimen 2,230 years old in northern Delingha, Qinghai; they do not detail the data source, except to say that it is based on a review of dendrochronological data sets, and that the age was determined based upon sampling in 2009. The greatest age is 2460 years for a tree with a crossdated ring-width record from 1230 BCE to 1229 CE, collected in Qinghai, China by Yang Bao and colleagues (doi.org/10.25921/w18b-y480).
Although details are lacking, in parts of its range this is one of the only trees on the landscape, so it was likely used by the indigenous peoples for firewood and various implements.
This may be the most dendrochronologically useful conifer in central Asia. Zhang and Qiu (2007) developed a 1017-year chronology. Peng et al (2008) studied variation in climate-growth response on an elevational gradient. 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. Qin et al. (2013) and Gao et al. (2013) characterized the climate-growth response for this species, and Wang et al. (2019) have studied its response (and vulnerability) to severe drought events. The most impressive study, though, was a 3500-year precipitation reconstruction by Yang et al. (2014). A comparative demographic study has looked at J. przewalskii and Picea crassifolia in the Qilian Shan (Wang et al. 2016); there have also been various modeling studies using these data.
The epithet remembers Polish naturalist Nikolai Przewalski (1839-1888), explorer of central Asia.
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.
Adams, R. P., and A. E. Schwarzbach. 2012. Taxonomy of the turbinate shaped seed cone taxa of Juniperus, section Sabina: sequence analysis of nrDNA and four cpDNA regions. Phytologia 94(3):388-403.
Adams, R. P., and A. E. Schwarzbach. 2013. Taxonomy of the turbinate shaped seed cone taxa of Juniperus, section Sabina: Revisited. Phytologia 95:122–124.
Gao L., X. Gou, Y. Deng, W. Liu, M. Yang and Z. Zhao. 2013. Climate–growth analysis of Qilian juniper across an altitudinal gradient in the central Qilian Mountains, northwest China. Trees 27:379-388.
Komarov. 1924. Botaniceskie Materialy Gerbarija Glavnogo Botaniceskogo Sada RSFSR 5: 28.
Li Zhonghu, Jiabin Zou, Kangshan Mao, Kao Lin, Haipeng Li, Jianquan Liu, Thomas Kallman, and Martin Lascoux. 2011. Population genetic evidence for complex evolutionary histories of four high altitude juniper species in the Qinghai–Tibetan Plateau. Evolution 66(3):831-845, doi:10.1111/j.1558-5646.2011.01466.x.
Liu, J., B. Yang, and D. B. Lindenmayer. 2019. The oldest trees in China and where to find them. Frontiers in Ecology and the Environment 17(6):319–322.
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.
Qin C., B. Yang, T. M. Melvin, Z. Fan, Y. Zhao, and K. R. Briffa. 2013. Radial Growth of Qilian Juniper on the Northeast Tibetan Plateau and Potential Climate Associations. PLoS ONE 8(11): e79362. https://doi.org/10.1371/journal.pone.0079362.
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.
Wang B., T. Chen, G. Xu, X. Lium, W. Wang, G. Wu, and Y. Zhang. 2016. Alpine timberline population dynamics under climate change: a comparison between Qilian juniper and Qinghai spruce tree species in the middle Qilian Mountains of northeast Tibetan Plateau. Boreas 45(3):411-422.
Wang X., B. Yang, and F. C. Ljungqvist. 2019. The Vulnerability of Qilian Juniper to Extreme Drought Events. Frontiers in Plant Science, DOI=10.3389/fpls.2019.01191.
Yang, B., Chun Qin, Jianglin Wang, Minhui He, Thomas M. Melvin, Timothy J. Osborn and Keith R. Briffa. 2014. A 3500-year tree-ring record of annual precipitation on the northeastern Tibetan Plateau. Proceedings of the National Academy of Sciences 111(8):2903-2908. doi: 10.1073/pnas.1319238111
Zhang, Q.-B. and H. Qiu. 2007. A millennium-long tree-ring chronology of Sabina przewalskii on northeastern Qinghai-Tibetan Plateau. Dendrochronologia 24(2-3): 91-95.
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.
Farjon (2005) provides a detailed account, with illustrations.
Last Modified 2024-11-27
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