Discover Life - Pinaceae: Pinus aristata Engelm.

Pinus aristata

Engelmann 1862

Common names

Rocky mountain bristlecone pine ( Elmore and Janish 1976 ), hickory pine ( Peattie 1950 ), Colorado bristlecone pine ( Kral 1993 ).

Taxonomic notes

Syn: Pinus balfouriana Greville & Balfour var. aristata (Engelmann) Engelmann ( Kral 1993 ).

Description

"Trees to 15m; trunk to 1m diam., strongly tapering, twisted; crown rounded, flattened (sheared), or irregular. Bark gray to red-brown, shallowly fissured, with long, flat, irregular ridges. Branches contorted; twigs pale red-brown, aging gray, puberulent, young branches resembling long bottlebrushes because of persistent leaves. Buds ovoid-acuminate, pale red-brown, ca. 1 cm, resinous. Leaves 5 per fascicle, upcurved, persisting 10-17 years, (2-)3-4 cm x 0.8-1 mm, mostly connivent, deep blue-green, with drops and scales of resin, abaxial surface with strong, narrow median groove, adaxial surfaces conspicuously whitened by stomates, margins entire or distantly serrulate, apex conic-acute to conic-subulate; sheath 0.5-1.5 cm, scales soon recurving, shed early. Pollen cones ellipsoid, ca. 10 mm, bluish to red. Seed cones maturing in 2 years, shedding seeds and falling soon thereafter, spreading, symmetric, lance-cylindric before opening, lance-ovoid to ovoid or cylindric when open, 6-11 cm, purple to brown, nearly sessile; apophyses much thickened; umbo central, with triangular base, extended into slender, brittle prickle 4-10 mm. Seeds obliquely obovoid; body 5-6 mm, gray-brown to near black; wing ca. 10-13 mm. 2 n =24." ( Kral 1993 ).

Needles of Pinus aristata are usually narrower and sharper than in P.longaeva and P.balfouriana , and the leaves almost always have a narrow, median groove on the abaxial surface ( Kral 1993 ).

Range

USA: Montane to subalpine areas of Colorado, New Mexico and Arizona (the San Francisco Peaks) at elevations of 2300 to 3650 meters ( Silba 1986 , Kral 1993 ). See also Thompson et al. (1999) .

Big tree

Diameter 107 cm, height 23 m, crown spread 12 m. Locality: Carson National Forest, NM. Also: Diameter 112 cm, height 22 m, crown spread 10 m. Locality: Colfax County, NM ( American Forests 1996 ).

Oldest

A crossdated age of 2,435 years was determined for specimen CB-90-11, sampled by Brunstein and Yamaguchi in central Colorado ( Brunstein and Yamaguchi 1992 , Brown 1996 ).

Dendrochronology

Little work has been done. Brunstein (1996) did an interesting study of frost rings over an impressive 2,500 year time span.

Ethnobotany

Observations

An ancient timberline grove can be seen along the Auto Road on Mt. Evans, Colorado. This grove has been somewhat vandalized by wood collectors. A more pristine stand can be found at timberline on the San Francisco Peaks of Arizona, although this requires a half-day walk to visit. The species also occurs as an early successional montane forest tree; in this role, it is plentiful in the western Pikes Peak area or Colorado, from the lower Peak west to the Woodland and Cripple Creek areas.

Remarks

White pine blister rust ( Cronartium ribicola ), an introduced fungal disease, has afflicted this and certain other white pines ( Peattie 1950 ).

On the San Francisco Peaks, this species is a principal host for the dwarf mistletoe Arceuthobium microcarpum ( Hawksworth and Wiens 1996 ).

Citations

Brunstein, F.C. 1996. Climatic significance of the bristlecone pine latewood frost-ring record at Almagre Mountain, Colorado, U.S.A. Arctic and Alpine Research 28(1): 65-76.

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© Copyright Steve Baskauf, 2002-2005 Pinus aristata, Whole tree