IV
The extraordinary forest luxuriance at the base of Mount Rainier is due to moisture and climate. The same heavy snowfalls which feed the glaciers store up water-supplies for forest and meadow. The winters at the base of the mountain are mild.
The lower valleys are covered with a dense growth of fir, hemlock, and cedar. Pushing skyward in competition for the sunlight, trees attain great heights. Protected from winter's severity by the thickness of the growth, and from fire by the dampness of the soil, great age is assured, which means thick and heavy trunks. The Douglas fir, easily the most important timber-tree of western America, here reaches its two hundred feet in massive forests, while occasional individuals grow two hundred and fifty to two hundred and seventy feet with a diameter of eight feet. The bark at the base of these monsters is sometimes ten inches thick. The western hemlock also reaches equal heights in competition for the light, with diameters of five feet or more. Red cedar, white pines of several varieties, several firs, and a variety of hemlocks complete the list of conifers. Deciduous trees are few and not important. Broad-leaved maples, cottonwoods, and alders are the principal species.
Higher up the mountain-slopes the forests thin and lessen in size, while increasing in picturesqueness. The Douglas fir and other monsters of the lower levels disappear, their places taken by other species. At an altitude of four thousand feet the Englemann spruce and other mountain-trees begin to appear, not in the massed ranks of the lower levels, but in groves bordering the flowered opens.
The extreme limit of tree growth on Mount Rainier is about seven thousand feet of altitude, above which one finds only occasional distorted, wind-tortured mountain-hemlocks. There is no well-defined timber-line, as on other lofty mountains. Avalanches and snow-slides keep the upper levels swept and bare.
The wild-flower catalogue is too long to enumerate here. John Muir expresses the belief that no other subalpine floral gardens excel Rainier's in profusion and gorgeousness. The region differs little from other Pacific regions of similar altitude in variety of species; in luxuriance it is unsurpassed.