Pseudotsuga macrocarpa description

Pseudotsuga macrocarpa (Vasey) Mayr 1890

Common Names

Bigcone Douglas-fir, bigcone spruce (2).

Taxonomic notes

Syn: Abies macrocarpa Vasey 1876; Pseudotsuga californica Flous; P.douglasii (Lindley) Carrière var. macrocarpa (Vasey) Engelmann (4).

Description

"Trees to 44 m; trunk to 230 cm dbh; crown broadly conic. Twigs slender, glabrous or pubescent. Leaves (20)25-45 × 1-1.5 mm, bluish green, apex mucronulate. Pollen cones pale yellow. Seed cones 9-20 × 4-7 cm. Seeds 9-12 mm. 2n=24" (4).

Range

USA: California, at 200-2400 m elevation. Habitat slopes, cliffs, and canyons, in chaparral and mixed coniferous forests. The northernmost stands of the species, in Kern County, are about 35 kilometers east of the closest approach of P.menziesii (4).

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 (1).

Big Tree

Height 44 m, dbh 213 cm, crown spread 26 m; in Angeles National Forest, CA (3).

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 (4).

Observations

Fairly easy to locate within its range. It is quite common in mixed pine-chaparral habitats of the San Gabriel Mountain just N of Los Angeles (CA), along CA Hwy 243 W of Mt. San Jacinto, and porbably in many other pine-chaparral habitats of the Transverse Ranges.

Remarks

Citations

(1) 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.

(2) Peattie, Donald Culross. 1950. A natural history of western trees. New York: Bonanza.

(3) American Forests. 1996. The 1996-1997 National Register of Big Trees. Washington, DC: American Forests.

(4) Barney Lipscomb at the Flora of North America web site.