Bhutan pine, Himalayan white pine (Farjon 1984).
Syn: P. excelsa Wall.; P. griffithii McClelland; P. chylla Lodd. (Farjon 1984).
Tree to 50+ m tall with straight trunk and short, downcurved branches. Branches longer in solitary trees, creating a dome-like crown. Bark on young trees smooth, becoming fissured with age. Branches in regularly spaced whorls, smooth. Young shoots glaucous, later turning pale grey-green, smooth, ribbed, darkening with age. Winter buds grey with an orange tinge, ovoid-conic, pointed. Leaves in fascicles of 5, basal sheaths deciduous, 15-20 cm long, often curved at the base, slender, flexible, abaxial side green, adaxial side with multiple bluish-white stomatal lines; usually pendant but in some trees spreading. Male strobili on lower branches, often in dense clusters on younger twigs. Female cones in groups of 1-6, 20-30 cm long, erect when young but later pendant [see photo], bluish-green when young, maturing to light brown with pale brown apophyses. Cone scales wedge-shaped, wide near the apex, apophysis grooved, ending in a blunt umbo; basal scales usually not, or only slightly, reflexed, very resinous (Farjon 1984).
Himal: southern flank, from Afghanistan through Pakistan, India, Tibet (China: Xizang), Nepal and Bhutan to Burma. Found in valleys and foothills at elevations of 1800-3900 m, sometimes in pure stands but often in association with conifers including Cedrus deodara, Abies pindrow, Picea smithiana and Juniperus excelsa subsp. polycarpos, and with broadleaved species including Quercus semecarpifolia, Betula utilis, ard Acer and Ilex species. It may also be associated with the more narrowly distributed pines Pinus kesiya and P. roxburghii. It is shade-intolerant, thus early seral (Farjon 1984, Sahni 1990, Singh and Yadav 2000). Hardy to Zone 8 (cold hardiness limit between -12.1°C and -6.7°C) (Bannister and Neuner 2001).
A study of glacier fluctuations by Singh and Yadav (2000) developed a live-tree tree ring chronology extending from 1590 to 1999, indicating that maximum ages exceed 410 years.
Exploratory work by Bhattacharyya et al. (1992) found that this species crossdates well and its growth is reasonably well correlated with climate. Quite a few other studies have also been done, mostly since 1985, mostly focusing either on general exploratory work or on sampling for dendroclimatic data networks. For details, see the Bibliography of Dendrochronology.
Vladimir Dinets (E-mail, 2004.11.14) reports that Kalam, in Pakistan's Swat Valley, has a large forest of Cedrus deodara with some Picea smithiana and Pinus wallichiana. He also found it growing along the trail to Nanga Parbat Base Camp. "The trailhead is accessible from Gilgit by a hired jeep, or from Raikot Bridge on the Karakoram Highway by hitchhiking (early morning only). Near the trailhead are some Pinus gerardiana, Juniperus semiglobosa and Cupressus torulosa, higher up—Pinus wallichiana and Picea smithiana (slim, but up to 50 m tall)." He also saw growing on north-facing slopes in Ayubia National Park near Muree, 2-3 hours from Islamabad). See Dinets (2004) for further detail.
Bhattacharyya, A., LaMarche, Jr., V.C., Hughes, M.K. 1992. Tree-ring chronologies from Nepal. Tree-Ring Bulletin 52:59-66. Available online at www.treeringsociety.org/TRBTRR/TRBvol52_59-66.pdf (accessed 2006.06.14).
Dinets, Vladimir. 2004. Ramadan in Pakistan. http://dinets.travel.ru/eibex.htm (2004.11.28).
Sahni, K. C. 1990. Gymnosperms of India and Adjacent Countries. Dehra Dun: Bishen Singh and Mahendra Pal Singh Pub., p. 169.
Singh, J., and R.R. Yadav. 2000. Tree-ring indications of recent glacier fluctuations in Gangotri, western Himalaya, India. Current Science 79(11): 1598-1601. Available online at www.ias.ac.in/currsci/dec102000/1598.pdf (accessed 2006.06.14).
Last Modified 2017-01-16