10 THE WESTERN HEMLOCK. 



kenzie, the first white man to cross the North American continent, 

 saw the Hemlock in latitude 52° on the coast of what is now British 

 Columbia. The first description of the tree was published in 1814 in 

 the journal of the Lewis and Clarke Expedition, which passed the win- 

 ter of 1805 near the mouth of the Columbia River. These explorers 

 spoke of it as a tree "four to six feet in diameter, straight, round, 

 and regularly tapering." 



The distribution of the species indicates clearly its chief require- 

 ments to be a cool and moist climate. Western Washington and 

 Oregon, where it reaches its best development, are divided into three 

 longitudinal belts, each with distinct characteristics of soil and climate. 

 The western strip, between the Pacific Ocean and the Coast Range (which 

 becomes the Olympic Mountains in the north), has a fertile, usually 

 clayey soil and an annual rainfall of from TO to 100 inches. This strip 

 contains a large proportion of Hemlock, in mixture with Spruce, Cedar, 

 and Red Fir. (See Frontispiece.) Between the Coast Range and the 

 foot of the Cascades lies a belt which, protected from the moist sea 

 winds, is comparatively dry. In Washington the soil is glacial drift, 

 consisting chiefly of gravels; in Oregon it forms the rich agricultural 

 lands along the Willamette and other rivers. In this belt there is 

 little Hemlock, the growth being nearly pure Red Fir, with Cedar on 

 the low ground, and some Pine. On ascending the west slopes of the 

 Cascades the change is again distinctly marked. The soil is of either 

 volcanic or sedimentary origin, and the increasing altitude causes con- 

 densation of the moisture which escapes the Coast Range and is carried 

 eastward over the central valley. Here the Hemlock again appears 

 and, at an altitude of from 1,500 to 3,500 feet, reaches its best develop- 

 ment, and is most free from insect attacks and from disease. 



ASSOCIATED SPECIES. 



Hemlock rarely occurs in pure stands of great extent, although 

 Clallam County. Wash., contains large forests of Hemlock, and there 

 are tracts in Jefferson and King counties in which the percentage of 

 other species is small. (PI. I.) It commonly occurs in a mixture in 

 which Red Fir is apt to be the prevailing species. (PI. II.) Along 

 the coast it is associated with Spruce and Cedar, and in northern Cali- 

 fornia with Redwood. Occurring up to an altitude of nearly 5.000 

 feet, it is almost always one of the many species which form the widely 

 varying mixture on the west slope of the Cascades. With Red Fir, 

 Spruce, Cedar, and White Fir, it constitutes the forest now being 

 lumbered in the foothills; higher, its associates are White Pine (PI. Ill, 

 tig. 2), Noble Fir, Amabilis Fir (PI. Ill, fig. 1), and, near its upper 

 limit, Alaska Cedar and the Alpine Hemlock. Toward the west slope 

 of the Rockies, the eastern limit of its range, it becomes more distinctly 

 a mountain tree and grows in what has been called the White Pine 



