Black Hemlock, Mountain Hemlock: Tsuga mertensiana (Synonyms: Abies hookeriana, Abies mertensiana, Hesperopeuce mertensiana, Picea hookeriana, Tsuga crassifolia, Tsuga mertensiana ssp. mertensiana)

The photo above shows the tip of a typical branch of mountain hemlock. The needles of this species are arranged around all sides of the branches and are somewhat thickened in cross-section and measure from 1-2 cm long. The cones are roughly elliptical in shape and measure from 3-7 cm long. The similar western hemlock has needles which are more 2-ranked on the sides of the twigs with the needles of unequal length. The cones of the western hemlock are roughly egg-shaped and measure from 1.5-2.5 cm long. Photographed at treeline at Crystal Lake on the western slopes of Mt. Adams......September 25, 2005.

The upper portion of mountain hemlock as seen near treeline along the Round the Mt. Trail #9 at the Aiken Lava Flow on the southern slopes of Mt. Adams........October 22, 2005. Notice how the tip of the tree arches to the side, a diagnostic identification feature for this genus. This species may be found from about 4000' up to treeline.

The photo above shows an unopened and open cone of mountain hemlock as seen near treeline along the Round the Mt. Trail #9 at the Aiken Lava Flow on the southern slopes of Mt. Adams........October 22, 2005. The cones of mountain hemlock measure from 2.5-7 cm long, while those of the western hemlock measure from 1.5-2.5 cm long.

The photo above shows a krummholtz mountain hemlock as seen along the South Climb Trail (below the toe of the Crescent Glacier) on the southern slopes of Mt. Adams........August 23, 2008. A conifer in such alpine conditions can grow to a normal width on those parts of the plant protected by a sufficient depth of snow during the winter. The upper part of the plant that extends beyond the protective blanket of snow is exposed to harsh, cold and drying winds and so grows at a much slower rate and thus is much reduced in size.