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Tree, ca. 100 cm dbh and 20 m tall, growing by the highway ca. 6 km above the town of Mt. Baldy, CA [C.J. Earle, 2004.04.13].

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Ripe pollen cones and foliage on the tree shown above [C.J. Earle, 2004.04.13].

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First-year seed cones on the tree show above [C.J. Earle, 2004.04.13].

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Seed cone, collected in Banner Canyon near Julian, CA; length about 15 cm [C.J. Earle, 2004.04.08].

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Bark on a tree ca. 80 cm dbh, in Banner Canyon [C.J. Earle, 2004.04.08].

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Range map (data from Burns and Honkala 1990; basemap from www.expediamaps.com.

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Ring structure on a cut section with ca. 50 cm radius; tree grew in town of Mt. Baldy, CA [C.J. Earle, 2004.04.14].

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Typical occurrence of P. macrocarpa on a north-facing slope in chaparral, near town of Mt. Baldy, CA [C.J. Earle, 2004.04.13].

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The largest known specimen of P. macrocarpa, in the town of Mt. Baldy, CA [C.J. Earle, 2004.04.14].

 

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Conservation status

Pseudotsuga macrocarpa

(Vasey) Mayr 1889

Common names

Bigcone Douglas-fir, bigcone spruce (Peattie 1950). As a member of the genus Pseudotsuga, it is not a spruce, but "bigcone spruce" is the name you will usually hear if you travel in this tree's native range.

Taxonomic notes

Synonymy (Farjon 1998):

Description

When the seed cones are not in evidence, it generally resembles interior Douglas fir (P. menziesii subsp. glauca) in bark and foliage characters, and somewhat in growth form; however, the species do not co-occur in their native habitats. It forms a tree that commonly attains 30 m height and 100 cm dbh, with a roughly conical crown that often bears some deformation due to the dry sites, poor soils and frequent fire that this tree must frequently contend with. The twigs are slender, glabrous or pubescent. The needles are (20-)25-45 × 1-1.5 mm, bluish green, with a mucronate tip. The pollen cones are pale yellow. The very distinctive seed cones are 9-20 × 4-7 cm; the bracts are often, but not always, exserted in the mature dry cone. Seeds are 9-12 mm long. 2n=24 (pers. obs. and Lipscomb 1993).

Distribution and Ecology

USA: California, at 200-2400 m elevation. Habitat slopes, cliffs, and canyons, in chaparral and mixed conifer forests. The northernmost stands of the species, in Kern County, are about 35 kilometers east of the closest approach of P. menziesii (Lipscomb 1993). Hardy to Zone 8 (cold hardiness limit between -12.1°C and -6.7°C) (Bannister and Neuner 2001). See also Thompson et al. (1999).

It is a common species in the Coulter pine (Pinus coulteri)—Hardwood phase of California mixed conifer forests, typically found on steep N-facing slopes and in ravines, i.e., sites with relatively low fire frequency. At the lowest elevations (c. 1100 m) it occurs as scattered individuals 15-30 m tall above a closed canopy of Quercus chrysolepis. At higher elevations (c. 1500 m) it becomes much more abundant (80-190 trees/ha) in a mixed Pseudotsuga-Quercus canopy. Although often codominant with Pinus coulteri and Quercus chrysolepis, it is typically found on relatively more mesic sites with lower fire frequency. Not surprisingly, then, it is also found in riparian habitats as a codominant with mesic hardwood species such as Acer macrophyllum and Populus trichocarpa (Barbour 1988).

Lanner (1999) reports that the tree typically survives fire, which is a common hazard since it often grows amid chaparral. The fire may scorch the needles from the branches, but epicormic buds soon sprout from upper branch surfaces and unburned trunks, and a tree that looked dead may soon return to full vigor.

Big tree

Dbh 213 cm, crown spread 26 m; in Angeles National Forest, CA (American Forests 2004). This tree (see photo) has been the species champion since the 1940's and has been named "Old Glory." It was 44 m tall until topped by a 1950's windstorm (Lanner 1999), but with its roots in a perennial stream and the care of its human neighbors, it should be around and growing for many years yet.

Oldest

Dendrochronology

About 20 chronologies have been developed, most of them used in a study of air pollution impacts on tree growth.

Ethnobotany

Although of no concern for timber, the species is valuable for esthetics and watershed protection (Lipscomb 1993).

Observations

Fairly easy to locate within its range. It is quite common in mixed pine-chaparral habitats of the San Gabriel Mountains just N of Los Angeles (CA), along CA Hwy 243 W of Mt. San Jacinto, and probably in many other pine-chaparral habitats of the Transverse Ranges. The largest specimen is in the town of Mt. Baldy, CA, growing in sight of Los Angeles (on days when the smog is not too bad), and the trail up Mt. San Antonio from the town of Mt. Baldy provides ample opportunities to observe this tree in habitat. It lines parts of Banner Canyon near Julian, CA; this is about the southernmost distribution of the species.

Remarks

The uncommonly large seeds surely have limited dispersal potential when driven by moderate winds; one wonders if birds or small mammals play a role in their dispersal.

A nice shot of a Ps. macrocarpa stand forms the opening image in Stanley Kubrick's 1953 film Fear and Desire.

Citations

Barbour, M.G. 1988. Californian upland forests and woodlands. P. 131-164 in Barbour, M.G. and W.D. Billings. North American Terrestrial Vegetation. Cambridge: Cambridge University Press.

See also

Burns and Honkala (1990).

Farjon (1990) provides a detailed account, with illustrations.

FEIS database.

Minnich, R.A. 1982. Pseudotsuga macrocarpa in Baja California? Madroño 29:22-31.

Last Modified 2013-06-05