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Pinus balfouriana



Pinus balfouriana - Foxtail pine
  • Pinus balfouriana - Foxtail pine    - Click to enlarge
  • Pinus balfouriana cones - Click to enlarge
  • Pinus balfouriana leaves - Click to enlarge

 

Scientific name: Pinus balfouriana   Greville & J. Balfour   1853

Synonyms: Pinus balfouriana subsp. balfouriana

Infraspecific taxa: Pinus balfouriana subsp. austrina R.J.Mastrog. & J.D.Mastrog.

Common names: Foxtail pine  

 

Description

Tree to 20(-25) m tall, with trunk to 1.5(-2.6) m in diameter. Bark gray or bright reddish brown, becoming narrowly and irregularly ridged and furrowed on breaking up into broader plates. Crown narrowly to broadly conical, becoming irregular with age, with numerous short, upwardly arching or long, gently downswept branches densely clothed with foliage (hence the common name, since these branches look, fancifully, like green foxtails). Twigs reddish brown, hairless or minutely hairy at first, becoming yellowish gray and bald with age. Buds 8-10 mm long, resinous. Needles in bundles of five, each needle 1.5-4 cm long, stiff, straight, and remaining tight together, lasting 7-30 years, dark bluish to yellowish green, without resin flakes. Individual needles with lines of stomates only on the inner faces, an undivided midvein, and two medium-sized resin canals touching the ungrooved epidermis of the outer face. Sheath scales 5-10 mm long, curling back and soon shed. Pollen cones 6-10 mm long, red. Seed cones 6-9(-11) cm long, egg-shaped and sharply tapered at the base, with 70-90 scales, purple before maturity, ripening brown to reddish brown, opening widely to release the seeds and then falling intact with the 7-to 18-mm-long stalk. Seed scales paddle-shaped, thin but thicker at the exposed tip, with diamond-shaped umbo on the exposed face bearing a minute, week prickle to 1 mm ling. Seed body about 7-10 mm long, pale with dark speckles, the easily detachable wing 10-20 mm long.

The species name honors John Hutton Balfour (1808 - 1884) director of the Royal Botanic Garden, Edinburgh, who described it using the name provided by the collector, John Jeffrey.

Klamath Mountains and southern Sierra Nevada of California. Often forming pure subalpine stads in the south or mixed with other montane conifers on the north, usually on upper slopes or exposed ridges; (1,600-)2,400-2,900(-3,700) m.

 

Conservation Status

Red List Category & Criteria: Near Threatened

Based on comprehensive sampling of specimens held in herbaria in California and elsewhere, and the fact that very few if any stands of this species would have an area of occupancy (AOO) larger than 4 km² an AOO of only 136 km² was calculated. There are two main areas, separated by nearly 500 km, but the northern area has two locations, one with a much smaller subpopulation than the other. Fragmentation and number of locations therefore also fall within the threshold for Endangered; however, the population appears to be stable at present and there is no evidence of past decline within the last few hundred years. Climate change and air pollution (the latter only relevant to the southern subpopulation) are potential threats. It is therefore appropriate to list this species as Near Threatened.

The total number of mature trees is not known, but the population is fragmented, first by a gap of nearly 500 km between the northern and southern (sub) populations, and second by the fact that individual stands are (widely) scattered within these two areas. Numbers of trees in each of these stands vary between a few score to many hundreds. Regeneration and growth to maturity are extremely slow in most stands and may be episodic; this means that if little or no regeneration is observed in a stand at present this will not be evidence of decline. A tree that lives for several millennia only needs to produce offspring a few times in that whole period to replace itself and maintain the population.

Pinus balfouriana occurs in the subalpine to alpine zones of the Klamath Mountains (the northern [sub]population) and of the southern Sierra Nevada (the southern [sub]population). In the north it is found at altitudes of between 1,600 m and 2,400 m a.s.l., in the south between 2,900 m and 3,700 m. Stands of this pine are very open and occur on dry, rocky, exposed high slopes and ridges, usually devoid of other significant vegetation. Stands may be pure or mixed with Pinus albicaulis, sometimes Juniperus occidentalis grows with it, too. Regeneration and growth are extremely slow and stands commonly look as if entirely composed of veteran trees of great age. Regeneration is probably episodal and may be linked with climatic cycles. Unlike its even longer lived 'cousin' Pinus longaeva, growing only 35-40 km to the east of the Sierra Nevada, little is known about the exact ages of some of the oldest trees, but they are likely to be more than 2000 years old.

This species may be at risk in the long term from climate change if this is continuing to accelerate, possibly bringing in competitors and/or pathogens it may not be able to cope with. At present, both disjunct populations are well protected within National Parks and National Forest Wilderness Areas and unaffected by long-term effects of fire suppression in forests as the trees usually occur in remote subalpine locations where such measures have not been undertaken. It would be profitable to study the (aut-)ecology of this species in more detail in order to be able to estimate risks under various climate change scenarios. The southern (sub)population in Kings Canyon N.P. and Sequoia N.P. are subject to air pollution from major urban centres such as Los Angeles. The effect, if any, on this species is as yet unknown and needs to be researched.

Foxtail pine is not a timber tree due to extremely slow growth and general inaccessibility of the stands of relatively small trees. The dense and hard wood is obviously of value for special uses like wood craft and some dead and down wood may be used for this purpose. Almost all stands of this pine are now within protected areas and felling as well as dead wood collecting are strictly prohibited there. This species was introduced to Britain in the early 1850s by the Scottish 'Oregon Association' through the services of John Jeffrey, who collected seeds of western American trees for the gentlemen who instituted the association for this purpose. It is still in cultivation for gardens, but rare and virtually restricted to collections of trees and shrubs. Only two cultivars have been named, both in the U.S.A.

This species is mostly present within protected areas, including famous national parks like Kings Canyon and Sequoia National Park.

 

Cultivars

Pinus balfouriana ‘Cherry Lady’
Pinus balfouriana ‘Dwarf’                               
Pinus balfouriana ‘Dwarf Form’                          
Pinus balfouriana ‘Mindy’    

 

References

  • Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.
  • Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.
  • IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland

Copyright © Aljos Farjon, James E. Eckenwalder, IUCN, Conifers Garden. All rights reserved.


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