Western hemlock (figs. 6 and 7) is usually associated with Douglas fir and red cedar, but sometimes forms a forest of nearly pure growth. The hemlock produces abundant seed each year, although it is more prolific at irregular intervals. The seeds germinate readily on decayed moss and rotten wood as well as upon the mineral soil. Seedlings frequently grow on fallen logs and extend their vigorous roots around the side until they reach the ground and become firmly anchored in it. Young hemlocks thrive in the shade. On logged-off areas which have not been burned over and which are partially shaded by uncut trees, the reproduction of hemlock springs up, to the exclusion of the more valuable Douglas fir.
[Illustration: FIG. 6.--The lower slope forest, near Longmire Springs, altitude 3,000 feet, here composed largely of western hemlock (_Tsuga heterophylla_); the tree on the extreme left is a Douglas fir (_Pseudotsuga taxifolia_).
The hemlock is long lived and grows slowly. The largest trees are from 200 to 500 years old and are usually hollow-hearted. The bark is thin and the tree very easily killed by ground fire. The wood of the hemlock is tough, light, and straight grained. It is not as durable as the Douglas fir and decays rapidly when exposed to the weather. The clear lumber is suitable for interior finish. The wood is also used for flooring, joists, lath, and paper pulp. The common and rough lumber does not find a ready market, except for the limited amount used in temporary construction. The western hemlock is, however, superior to the eastern hemlock, and its value will probably be recognized as its usefulness for many purposes becomes better known.
[Illustration: FIG. 7.--A forest of Douglas fir, with an understory of western hemlock, on the lower slopes of the hills, Mount Rainier National Park.
The western white pine (fig. 8) is found from southern Alaska to northern California. In the park it occurs occasionally up to 4,000 feet. It usually grows on level benches and gentle slopes associated with Douglas fir, western hemlock, and noble and amabilis fir. It reaches its best development at elevations of from 3,000 to 3,500 feet, where it attains a height of 150 feet and a diameter of 40 inches. The shaft is straight, cylindrical, and clear of limbs. It bears a small, narrow crown of drooping branches. In open areas, where it is exposed to sunlight, its mode of growth is wholly different. The trunk is short, rapidly tapering, and bears wide-spreading branches nearly to the ground. At high elevations the western white pine is very short and stunted.