Larix potaninii var himalaica (W.C.Cheng & L.K.Fu) Farjon & Silba
This variety is restricted to a few valleys near Mt Everest on both Chinese and Nepalese sides. It is assessed as Near Threatened due to its restricted distribution, the likelihood that it is exploited but uncertainty as to the extent of that exploitation.
Description
Taxonomic Notes
The Flora of China recognises this variety as a distinct species.
Distribution
Recorded from China: S Xizang [Tibet] (Gyirong river); and Nepal (Langtang Khola). Its full distribution is uncertain
Habitat and Ecology
Grows in dry high altitude scrubland with Caragana, Cotoneaster, and Berberis.
Human Uses
Larix potaninii is an important timber tree in the western mountains of China. Its wood is durable and can be used for construction purposes, mining props and railway sleepers, as well as milled for veneer and pulped for the paper industry. This variety is liekly exploited for the same purposes.
Conservation Status
Global Status & Rationale
This variety appears to have a very restricted range being recorded from only two localities fairly close to each other. There are valleys in between the two known localities with apparently suitable habitat in which this species could occur, so it may well be more widespread and more common than present collections indicate. There may be some local use, but it is not known if this poses a threat or not. One possibility would be to list this taxon as Vulnerable under criterion D2, but it is not clear what potential threat could drive it towards extinction in a short space of time. The variety is therefore listed as Near Threatened because it has a limited range, certainly has an extent of occurrence <20,000 km², and an area of occupancy <2,000 km². If there are threats, then it would most likely be known from at least two locations, possibly more, but certainly less than ten. However, currently there is no indication of any continuing decline. It almost qualifies as threatened under criteria B1 and B2, and possibly D2.
Global Threats
This variety apparently occupies a limited area as it is known with certainty only from some valleys in the Mt. Everest area, both on the Chinese and Nepalese side of the border. There may be some localized logging of the species, but it is not known if this poses a threat or not. The population on the Tibetan side is reported to suffer from increasing droughts
Conservation Actions
In Xizang [Tibet] it occurs in the valley of the Gyirong River (no protected status), and in Nepal in Langtang National Park.
References and further reading
Christian, T., Rushforth, K. & Luscombe, D. 2013. Larix potaninii var. himalaica. The IUCN Red List of Threatened Species 2013: e.T34164A2849037. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T34164A2849037.en. Downloaded on 12 December 2016.
Debreczy, Z., I. Racz 2011. Conifers around the world. Volume 1. Budapest: DendroPress Ltd.
Farjon, A. 2010. A Handbook of the World's Conifers. Koninklijke Brill, Leiden
Wu Zhengyi & Peter H. Raven (eds.) 1999. Flora of China: Vol.4. Cycadaceae through Fagaceae. Science Press (Beijing) & Missouri Botanical Garden (St. Louis). 449 pp.
