The alpine fir occurs in unmixed stands, but is often associated with the mountain hemlock. At the lower levels of its range it is a fair-sized tree 50 or 60 feet high. The crown of deep-green foliage is broad at the base and tapers to the top, where it terminates in a slender, pointed tip. At its upper limit it becomes a stunted shrub, with wide extended branches resting on the ground.
The alpine fir bears upright clusters of deep-purple cones. It seeds sparingly each year. The seasons of heavy seed production occur at intervals of three or four years. The wood is soft and splits easily. It is of no commercial value. The tree is easily killed by fire, which blisters the thin bark and frequently springs into the drooping lower branches.
GRAND FIR (ABIES GRANDIS.)[4]
The grand fir ([fig. 14]), like several other species, is generally given the name of white fir on account of its smooth, light-colored bark. It is a common tree in the river bottoms from British Columbia south to northern California. In the Mount Rainier National Park it occurs up to 4,000 feet. The grand fir is a moisture-loving tree and is usually found firmly rooted in deep alluvial bottom lands along the banks of streams. With the Douglas fir, hemlock, and red cedar it forms the dense forest characteristic of the lower mountain valleys.
In favorable conditions the grand fir grows to a height of from 100 to 200 feet and is a noble and stately tree. The trunk tapers rapidly and bears a rounded pyramidal crown. In dense forests the trunk is clear for half its height, but where the trees stand in the open it carries its branches nearly to the ground. The leaves are a bright and shining green. The large light-green cones mature early in the fall. The wood is soft and very heavy before it is seasoned. It rots in a very short time when laid on the ground. When dry it is white, coarse-grained, light, and odorous. It is used for interior finish and for crates and packing boxes, but is of little value commercially.
ENGELMANN SPRUCE (PICEA ENGELMANNI).
The Engelmann spruce ([fig. 15]) is a mountain tree ranging from British Columbia to Arizona and New Mexico. It is common along the summit and on the east side of the Cascade Range and occurs on the northeastern and eastern slopes of Mount Rainier at elevations of from 3,500 to 6,000 feet.
This tree requires a moist soil and prefers cool northern exposures. Up to 5,000 feet it commonly grows in sheltered basins at the head of canyons and in stream valleys. At its upper limits it is common on flats and depressions and about lakes on level summits. It avoids steep mountain sides and exposed situations.
