Whitebark pine (Pa) - Pinus albicaulis
Whitebark pine is a small - to medium-sized (rarely >30 m tall), slow-growing, long-lived tree of high mountains. When mature, it develops multi-stemmed growth form, with typically long branches and upswept branched crown, with brown, scaly bark. It is not a timber crop species, but is valued for watershed protection and aesthetics. Its seeds are an important food for grizzly bears and other wildlife.
|Geographic Range||Geographic element:
Western North American/mainly Cordilleran and less Pacific
Distribution in Western North America:
(central) in the Pacific region; central and south in the Cordilleran region
(alpine tundra) - subalpine boreal - (cool temperate)
(montane) - subalpine
Occurrence in biogeoclimatic zones:
(lower, southern AT), upper submaritime MH, upper southern ESSF, (upper southern ICH)
Range of soil moisture regimes:
(very dry) - moderately dry - slightly dry - fresh - (moist) - (very moist)
Range of soil nutrient regimes:
poor - medium - rich
The most productive growth of whitebark pine occurs on rich sites (it is absent on very poor sites); therefore, it could be concluded from field observations carried out by Krajina (1969) that whitebark pine requires for productive growth higher amounts of calcium and magnesium than does lodgepole pine.
|Root System Characteristics||On most sites, whitebark pine develops a deep and spreading root system. It is well anchored, even on the rocky substrates and is seldom uprooted despite its large, exposed crown and the violent winds to which it is subjected. Roots of whitebark pine are associated with both ecto- and endo-mycorrhizae.|
|Associated tree species and successional role||In British Columbia, whitebark pine grows in pure or mixed-species stands, mainly in broadly even-aged stands. With increasing elevation, the species grows in isolated clumps on exposed ridges and as krummholz. Whitebark pine is a pioneer (primary succession) and is present in early, mid-, and even late stages of secondary succession. During secondary succession, whitebark pine may be replaced by mountain hemlock (MH zone) or Engelmann spruce and subalpine fir (ESSF zone).|
|Genetics||Most of the wide phenotypic variation in growth form in whitebark pine is apparently the result of differences in site and climate.|
|Notes||Whitebark pines greatest values are for wildlife habitat, watershed protection, and aesthetics. More detailed silvics information is given by:
Arno, S.F. and R.J. Hoff. 1990. Pinus albicaulis. Pp. 268-279 in R.M. Burns and B.H. Honkala (technical coordinators) Silvics of North America, Vol 1. Agri. Handbook 654, USDA For. Serv., Washington, D.C.