The mountain hemlock (figs. 18, 19, and 20) is found on the Pacific
coast from the Sierras of California to the northern part of Alaska
where it grows at sea level. On Mount Rainier it occurs at altitudes of
from 3,500 to 7,500 feet. It forms dense forests under 4,500 feet, where
it is often a fair-sized tree 50 to 90 feet high. With the ascent of the
mountain it diminishes in height and the branches become gnarled and
twisted. Near timber line the trunk is dwarfed and bent at the base and
the crown becomes a flattened mass of branches lying close to the ground
(fig. 20).
[Illustration: FIG. 19.--Two solitary mountain hemlocks (_Tsuga
mertensiana_), Spray Park, Mount Rainier National Park.