Tsuga mertensiana subsp. grandicona

Farjon 1988

Common names

In common usage it is not distinguished from the type. A reasonable vernacular name would be Sierra hemlock or California hemlock.

Taxonomic notes

Synonymy:

• Abies hookeriana A. Murray;
• Picea (Tsuga) hookeriana (A. Murray) Bertrand;
• Pinus hookeriana (A. Murray) McNab;
• Tsuga hookeriana (A. Murray) Carrière;
• T. pattoniana var. hookeriana (A. Murray) Lemmon;
• × Tsuga-Picea hookeriana (A. Murray) M. Van Campo-Duplan and Gaussen;
• T. roezlii Carrière;
• T. crassifolia Flous.

Description

Trees to 40 m tall and 150 cm dbh; crown conic. Bark charcoal gray to reddish brown, scaly and deeply fissured. Twigs yellow-brown, densely pubescent. Buds oblong, 3-4 mm. Needles 10-25(30) mm, tending to point more forward along shoot than in subsp. mertensiana, thickened centrally along midline, somewhat rounded or 4-angled in cross section, both surfaces strongly glaucous, with conspicuous stomatal bands; margins entire. Seed cones green or violet ripening yellow-brown, oblong-cylindric, (3.5)4-6.5 × 2.5-3.5 cm (open); scales pubescent, broadly fan-shaped, 11-l5 × 11-15 mm, apex rounded. Differs from subsp. mertensiana mainly in the larger (particularly broader) cones, with larger scales; the cones are also less often purple before maturity (Farjon 1990).

Distribution and Ecology

USA: California, and just into southernmost Oregon and westernmost Nevada, in the Sierra Nevada, Klamath, and southern Siskiyou ranges at (1220-)1800-3350 m elevation. In the western Siskiyous along the Del Norte-Siskiyou County line, mountain hemlock drops as low as 1220 m on Bear Basin Butte. Its southernmost occurrence in the coastal ranges is a tiny population on Black Rock Mountain near North Yolla Bolly. In the California Cascades, it is relatively uncommon. It is found on Mount Shasta, and in Shasta County it grows on Magee Peak. In the nearby Latour State Forest a few trees grow as low as 1830 m. It also occurs in the Lassen Peak region between 2280 and 2800 m elevation. It is again abundant in the Sierra Nevada. The main Sierra Nevada population starts in Sierra County and runs almost continuously to Fresno County. In the southern Sierra Nevada, mountain hemlock ranges in elevation up to 3540 m. Its extreme southern limit is reached near Silliman Lake in Tulare County (Griffin and Critchfield 1972). Habitat: moist mountain forests, mostly in sheltered north-facing sites close to alpine timberline (Parsons 1971, Farjon 1988, Farjon 1990). USDA hardiness zone 6.

Remarkable Specimens

The largest on record was height 34 m, dbh 224 cm, crown spread 13 m, in Alpine County, California (American Forests 1996); also height 45 m, dbh 183 cm, at head of Crystal Creek, Kings Canyon National Park, California (Parsons 1971; a pre-1971 measurement, so may be dead).

Ethnobotany

It is adaptable to a wide variety of climatic conditions and is widely used as an ornamental, but it is slow to start and difficult to establish.

Observations

Remarks

The epithet refers to the size of the cones, which are larger than those on the type variety.

Citations

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

Farjon, Aljos. 1988. Taxonomic notes on Pinaceae 1. Proc. Konin. Ned. Akad. Wetensch. ser. C Bot., 91: 31-42.

Farjon, Aljos. 1990. Pinaceae: drawings and descriptions of the genera Abies, Cedrus, Pseudolarix, Keteleeria, Nothotsuga, Tsuga, Cathaya, Pseudotsuga, Larix and Picea. Königstein: Koeltz Scientific Books.

Parsons, D. J. 1971. The southern extensions of Tsuga mertensiana (mountain hemlock) in the Sierra Nevada. Madroño 21: 536-539. Available: Biodiversity Heritage Library, accessed 2021.12.19.

This page edited with the help of M. P. Frankis, 1999.02.

See also