Tsuga mertensiana subsp. grandicona
In common usage it is not distinguished from the type. A reasonable vernacular name would be Sierra hemlock or California hemlock.
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).
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.
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).
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.
Farjon, Aljos. 1988. Taxonomic notes on Pinaceae 1. Proc. Konin. Ned. Akad. Wetensch. ser. C Bot., 91: 31-42.
Parsons, D.J. 1971. The southern extensions of Tsuga mertensiana (mountain hemlock) in the Sierra Nevada. Madroño 21: 536-539.
This page edited with the help of M.P. Frankis, 1999.02.
Last Modified 2012-11-23