J. pingii and other conifers, Baima Shan

J. pingii and other conifers, Baima Shan

© A. Farjon

Cupressaceae

Juniperus pingii W.C.Cheng

A variable, high altitude juniper that is usually found as a prostrate shurb (var wilsonii) in SW China and on the Tibetan Plateau. Grazing and firewood collection have led to a suspected reduction of almost 30% so that it has been assessed as Near Threatened.

Description

Taxonomic Notes

The taxonomy of this variable species is controversial; several varieties have been described. The IUCN Redlist recognises four: var. wilsonii (a prostrate shrub and the most common and widespread form), var. pingii (a much rarer tree form), var. miehii (another prostrate form only known from a locality in the upper Zangbo River basin and var. chengii (only known from the type specimen collected in 1937 from near Zhongdian). The last two varieties are very poorly known and have been assesed as Data Deficient. Several other varieties have been described and one, var. carinata has been recognised as a distinct species based on differences in leaf oils and DNA profiles (Adams 2000, 2014)

Distribution

Endemic to China: Gansu (Min Shan), Hubei (Daba Shan), S Qinghai, Shaanxi (Qin Ling Mts.), W Sichuan, NW Yunnan, Xizang [Tibet].

The global population of Juniperus pingii is poorly known, in part due to misidentifications but also to incomplete inventories of remote mountain areas. It seems to be quite scarce and, due to deforestation to make way for pasture, decreasing. It is also exploited for firewood and incense.

Individual trees and prostrate shrubs may live for several hundred years (Li et al. 2007).

Habitat and Ecology

The most common and widespread variety, J. pingii var. wilsonii is a low shrub. Juniperus pingii var. chengii was described as a small tree. The tree form of the species occurs below the tree line in subalpine forest or woodland, usually in clearings of Abies or Picea forest, or in more open Pinus densata and Larix potaninii woodland; where it can occur together with its decumbent form J. pingii var. wilsonii and with J. squamata. Its upper altitudinal limit is around 4,500 m a.s.l.; the lower limit is uncertain.

Human Uses

An important source of firewood at high elevations. Its slow growth, sensitivity to precipitation also make it useful for dendroclimatology (Liang et al. 2012).

Conservation Status

Global Status and Rationale

Near Threatened (VU B2ab(iii)

As the most widespread and common of its varieties, the shrubby var. wilsonii is assessed as Near Threatened, and as the other varieties are poorly known, the species as a whole is also assessed as Near Threatened (almost qualifies for a threatened category under criterion B2ab(ii,iii).

Global Threats

The tree form is apparently quite rare, but its remoteness has until the present been a safeguard against threats from human interference. On the other hand, increased pressure from grazing is likely to have had a negative impact on regeneration in certain areas (A. Farjon field observations in NW Yunnan, 2000).

Conservation Actions

The species occurs within several protected areas.

References and further reading

  1. Adams, R.P. 2000. Systematics of one seeded Juniperus of the eastern hemisphere based on leaf essential oils and random amplified polymorphic DNAs (RAPD). Biochemical Systematics and Ecology 28:529-543
  2. Adams, R. 2014. Junipers of the world; the genus Juniperus. 4th Edition. USA: Trafford. 415 pp.
  3. Farjon, A. 2010. A Handbook of the World's Conifers. Koninklijke Brill, Leiden.
  4. Li, S., X. Ye, D. Wang, L. Li, W. Lin, L. Wang 2007. Age structure of Sabina pingii in Yele Natural Reserve of Sichuan Province. J. Sichuan Univ. Nat. Sci. 44(1):186-190.
  5. Li, N., Carter, G. & Farjon, A. 2013. Juniperus pingii. The IUCN Red List of Threatened Species 2013: e.T34140A2847602. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T34140A2847602.en. Downloaded on 08 December 2016.
  6. Liang, E., X. Lu, P. Ren, X. Li, L. Zhu & D. Eckstein 2012. Annual increments of juniper dwarf shrubs above the tree line on the central Tibetan Plateau: a useful climatic proxy. Annals of Botany 109:721-728.