Pinus ponderosa subsp. scopulorum

(Engelmann) E. Murray 1982

Common Names

Rocky Mountain yellow pine (Peattie 1950), Rocky Mountain ponderosa pine (Kral 1993).

Taxonomic notes

Syn: P. scopulorum (Engelmann) Lemmon 1897; P. ponderosa var. scopulorum Engelmann 1880.

This subspecies was formerly combined with subsp. brachyptera as P. ponderosa var. scopulorum Engelmann. However, the two subspecies are readily distinguished by the smaller seeds, green cones, and frequently two leaved fascicles of subsp. scopulorum.

It intergrades with P. ponderosa subsp. ponderosa in Montana at about 112°W. longitude.

Description

Trees to 24 m tall and 150 cm dbh. Twigs mostly red-brown, rarely glaucous. Leaves 2-3 per fascicle, (7-)10-17 cm × (1.2-)1.4-2 mm. Pollen cones yellow. Seed cones mostly symmetric, 5-10 cm; green when immature, apophyses of fertile scales moderately raised; umbo low pyramidal, narrowing acuminately to a stout-based prickle or short sharp spur. Seed body 3-4 mm; wing to 15 mm (Little 1980, Kral 1993).

Range

USA: Montana (E from 112° W), North Dakota, South Dakota, Wyoming, Utah, E Nevada, Colorado, Nebraska, Oklahoma. Mostly at 1000-3000 m (Kral 1993).

Big tree

Diameter 164 cm, height 41.5 m. Locality: Lee Canyon in the Spring Mountains of southern Nevada (Robert Van Pelt e-mail 2004.02.04). The tallest tree is in the San Juan Mountain of Colorado, and was measured by Bob Leverett in 2009 at 48.98 m tall and 86.6 cm dbh (Robert Van Pelt e-mail 2009.06.22). Another very large/tall tree is about 20 miles southeast of Pagosa Springs, Colorado: 43.9 m tall and 145 cm DBH in 2003 (Robert Van Pelt e-mail 2007.10.23).

Oldest

A tree collected in the Wah Wah Mountains of Utah by S. Kitchen had a crossdated age of 929 years (RMTRR 2006). Also, a crossdated age of 843 years for specimen BRY4002, collected in central UT by Schulman in 1956 (Brown 1996). There is also an old but credible record of a ring count of 1047 from a tree in southwestern Colorado (Mills 1914).

Dendrochronology

Ethnobotany

This is the most important timber pine of the Rocky Mountains (Kral 1993).

Observations

Widely enountered throughout most of its range. In my experience, dense and continuous stands may be seen in the Black Hills of South Dakota, so named for the dense stands of ponderosa covering their slopes. Exceptionally old and picturesque trees may be found throughout the deserts of southeast Utah, particularly on the lower slopes of the Abajo and La Sal Mountains; and at Vedauwoo in southeast Wyoming.

Remarks

This species is a principal host for the dwarf mistletoe Arceuthobium vaginatum subsp. cryptopodum (Hawksworth and Wiens 1996).

Citations

Mills, Enos A. 1914. The story of a thousand year pine. Houghton Mifflin Co. Boston, MA. The story can be found online (bless those copyright expiration laws!) HERE.

Thanks to M.P. Frankis for his assistance with the Taxomonic Notes for this taxon.

See also

FEIS database.