MOUNTAIN HEMLOCK.
(Tsuga mertensiana)

This is one of the most common trees of the sub-alpine and timberline zones and is the chief associate of the alpine fir, except in the Yakima Park (Sunrise) area where it is replaced by the white-barked pine. While, at best, it has a rather ragged appearance it is, nevertheless, a beautiful and interesting tree. It may be readily distinguished from the spire-like alpine fir by the weak and drooping central leader and the graceful sweep of the branches which lift upward at the ends so that, in silhouette, the form of this tree resembles the architecture of a Chinese pagoda. In the rigorous timberline regions, of course, such factors are not characteristic as the tree is twisted, contorted, and other wise modified in appearance by high winds and deep snows.

The mountain hemlock is not a large tree. When growing under conditions which are not extreme it is generally from 25-75 feet tall and from 6-24 inches in diameter at maturity. When growing on slopes the base of the trunk is invariably bowed, due to the deep snow which in the tree's youth weighed it down during the greater part of the year and prevented it from growing erect. The bark is rough, scaly, furrowed and a dark grey in color on its outer surface. The inner bark has the characteristic maroon-red shade of the western hemlock of the lower elevations, however. The foliage is very dense and a dark yellow-green in color. Individual needles are blunt, rather plump instead of flat, soft to the touch, one inch or less in length and narrowed at the base into a short, slender petiole. While they grow from all sides of the branch they often seem thicker upon the upper portion. The cones are one of the most attractive features of this tree. These are generally produced in great numbers and, at maturity, before the scales open to liberate the seeds, are a deep violet-purple in color. They are from 1-1/2 - 2-1/2 inches long and borne at the ends of the branchlets. The wood is fine grained, soft and a pale brown in color. As one might expect, it is a tree of slow growth. A specimen in the park museum at Longmire, which is 5 inches in diameter, was over 100 years old when cut and it is very likely that some of tine larger trees are from 300 to 400 years of age.

Its botanical range includes the high alpine and timber line sections of the mountains along the Pacific Coast from Alaska to central California and, inland, in similar situations of northern Idaho and western Montana.

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