Earthquake Storms
The avalanche taluses, leaning against the walls at intervals of a mile or two, are among the most striking and interesting of the secondary features of the Valley. They are from about three to five hundred feet high, made up of huge, angular, well-preserved, unshifting boulders, and instead of being slowly weathered from the cliffs like ordinary taluses, they were all formed suddenly and simultaneously by a great earthquake that occurred at least three centuries ago. And though thus hurled into existence in a few seconds or minutes, they are the least changeable of all the Sierra soil-beds. Excepting those which were launched directly into the channels of swift rivers, scarcely one of their wedged and interlacing boulders has moved since the day of their creation; and though mostly made up of huge blocks of granite, many of them from ten to fifty feet cube, weighing thousands of tons with only a few small chips, trees and shrubs make out to live and thrive on them and even delicate herbaceous plants—draperia, collomia, zauschneria, etc., soothing and coloring their wild rugged slopes with gardens and groves.
I was long in doubt on some points concerning the origin of those taluses. Plainly enough they were derived from the cliffs above them, because they are of the size of scars on the wall, the rough angular surface of which contrasts with the rounded, glaciated, unfractured parts. It was plain, too, that instead of being made up of material slowly and gradually weathered from the cliffs like ordinary taluses, almost every one of them had been formed suddenly in a single avalanche, and had not been increased in size during the last three or four centuries, for trees three or four hundred years old are growing on them, some standing at the top close to the wall without a bruise or broken branch, showing that scarcely a single boulder had ever fallen among them. Furthermore, all these taluses throughout the Range seemed by the trees and lichens growing on them to be of the same age. All the phenomena thus pointed straight to a grand ancient earthquake. But for years I left the question open, and went on from cañon to cañon, observing again and again; measuring the heights of taluses throughout the Range on both flanks, and the variations in the angles of their surface slopes; studying the way their boulders had been assorted and related and brought to rest, and their correspondence in size with the cleavage joints of the cliffs from whence they were derived, cautious about making up my mind. But at last all doubt as to their formation vanished.
At half-past two o’clock of a moonlit morning in March, I was awakened by a tremendous earthquake, and though I had never before enjoyed a storm of this sort, the strange thrilling motion could not be mistaken, and I ran out of my cabin, both glad and frightened, shouting, “A noble earthquake! A noble earthquake!” feeling sure I was going to learn something. The shocks were so violent and varied, and succeeded one another so closely, that I had to balance myself carefully in walking as if on the deck of a ship among waves, and it seemed impossible that the high cliffs of the Valley could escape being shattered. In particular, I feared that the sheer-fronted Sentinel Rock, towering above my cabin, would be shaken down, and I took shelter back of a large yellow pine, hoping that it might protect me from at least the smaller outbounding boulders. For a minute or two the shocks became more and more violent—flashing horizontal thrusts mixed with a few twists and battering, explosive, upheaving jolts,—as if Nature were wrecking her Yosemite temple, and getting ready to build a still better one.
I was now convinced before a single boulder had fallen that earthquakes were the talus-makers and positive proof soon came. It was a calm moonlight night, and no sound was heard for the first minute or so, save low, muffled, underground, bubbling rumblings, and the whispering and rustling of the agitated trees, as if Nature were holding her breath. Then, suddenly, out of the strange silence and strange motion there came a tremendous roar. The Eagle Rock on the south wall, about a half a mile up the Valley, gave way and I saw it falling in thousands of the great boulders I had so long been studying, pouring to the Valley floor in a free curve luminous from friction, making a terribly sublime spectacle—an arc of glowing, passionate fire, fifteen hundred feet span, as true in form and as serene in beauty as a rainbow in the midst of the stupendous, roaring rock-storm. The sound was so tremendously deep and broad and earnest, the whole earth like a living creature seemed to have at last found a voice and to be calling to her sister planets. In trying to tell something of the size of this awful sound it seems to me that if all the thunder of all the storms I had ever heard were condensed into one roar it would not equal this rock-roar at the birth of a mountain talus. Think, then, of the roar that arose to heaven at the simultaneous birth of all the thousands of ancient cañon-taluses throughout the length and breadth of the Range!
The first severe shocks were soon over, and eager to examine the new-born talus I ran up the Valley in the moonlight and climbed upon it before the huge blocks, after their fiery flight, had come to complete rest. They were slowly settling into their places, chafing, grating against one another, groaning, and whispering; but no motion was visible except in a stream of small fragments pattering down the face of the cliff. A cloud of dust particles, lighted by the moon, floated out across the whole breadth of the Valley, forming a ceiling that lasted until after sunrise, and the air was filled with the odor of crushed Douglas spruces from a grove that had been mowed down and mashed like weeds.
After the ground began to calm I ran across the meadow to the river to see in what direction it was flowing and was glad to find that down the Valley was still down. Its waters were muddy from portions of its banks having given way, but it was flowing around its curves and over its ripples and shallows with ordinary tones and gestures. The mud would soon be cleared away and the raw slips on the banks would be the only visible record of the shaking it suffered.
The Upper Yosemite Fall, glowing white in the moonlight, seemed to know nothing of the earthquake, manifesting no change in form or voice, as far as I could see or hear.
After a second startling shock, about half-past three o’clock, the ground continued to tremble gently, and smooth, hollow rumbling sounds, not always distinguishable from the rounded, bumping, explosive tones of the falls, came from deep in the mountains in a northern direction.
The few Indians fled from their huts to the middle of the Valley, fearing that angry spirits were trying to kill them; and, as I afterward learned, most of the Yosemite tribe, who were spending the winter at their village on Bull Creek forty miles away, were so terrified that they ran into the river and washed themselves,—getting themselves clean enough to say their prayers, I suppose, or to die. I asked Dick, one of the Indians with whom I was acquainted, “What made the ground shake and jump so much?” He only shook his head and said, “No good. No good,” and looked appealingly to me to give him hope that his life was to be spared.
In the morning I found the few white settlers assembled in front of the old Hutchings Hotel comparing notes and meditating flight to the lowlands, seemingly as sorely frightened as the Indians. Shortly after sunrise a low, blunt, muffled rumbling, like distant thunder, was followed by another series of shocks, which, though not nearly so severe as the first, made the cliffs and domes tremble like jelly, and the big pines and oaks thrill and swish and wave their branches with startling effect. Then the talkers were suddenly hushed, and the solemnity on their faces was sublime. One in particular of these winter neighbors, a somewhat speculative thinker with whom I had often conversed, was a firm believer in the cataclysmic origin of the Valley; and I now jokingly remarked that his wild tumble-down-and-engulfment hypothesis might soon be proved, since these underground rumblings and shakings might be the forerunners of another Yosemite-making cataclysm, which would perhaps double the depth of the Valley by swallowing the floor, leaving the ends of the roads and trails dangling three or four thousand feet in the air. Just then came the third series of shocks, and it was fine to see how awfully silent and solemn he became. His belief in the existence of a mysterious abyss, into which the suspended floor of the Valley and all the domes and battlements of the walls might at any moment go roaring down, mightily troubled him. To diminish his fears and laugh him into something like reasonable faith, I said, “Come, cheer up; smile a little and clap your hands, now that kind Mother Earth is trotting us on her knee to amuse us and make us good.” But the well-meant joke seemed irreverent and utterly failed, as if only prayerful terror could rightly belong to the wild beauty-making business. Even after all the heavier shocks were over I could do nothing to reassure him, on the contrary, he handed me the keys of his little store to keep, saying that with a companion of like mind he was going to the lowlands to stay until the fate of poor, trembling Yosemite was settled. In vain I rallied them on their fears, calling attention to the strength of the granite walls of our Valley home, the very best and solidest masonry in the world, and less likely to collapse and sink than the sedimentary lowlands to which they were looking for safety; and saying that in any case they sometime would have to die, and so grand a burial was not to be slighted. But they were too seriously panic-stricken to get comfort from anything I could say.
During the third severe shock the trees were so violently shaken that the birds flew out with frightened cries. In particular, I noticed two robins flying in terror from a leafless oak, the branches of which swished and quivered as if struck by a heavy battering-ram. Exceedingly interesting were the flashing and quivering of the elastic needles of the pines in the sunlight and the waving up and down of the branches while the trunks stood rigid. There was no swaying, waving or swirling as in wind-storms, but quick, quivering jerks, and at times the heavy tasseled branches moved as if they had all been pressed down against the trunk and suddenly let go, to spring up and vibrate until they came to rest again. Only the owls seemed to be undisturbed. Before the rumbling echoes had died away a hollow-voiced owl began to hoot in philosophical tranquillity from near the edge of the new talus as if nothing extraordinary had occurred, although, perhaps, he was curious to know what all the noise was about. His “hoot-too-hoot-too-whoo” might have meant, “what’s a’ the steer, kimmer?”
It was long before the Valley found perfect rest. The rocks trembled more or less every day for over two months, and I kept a bucket of water on my table to learn what I could of the movements. The blunt thunder in the depths of the mountains was usually followed by sudden jarring, horizontal thrusts from the northward, often succeeded by twisting, upjolting movements. More than a month after the first great shock, when I was standing on a fallen tree up the Valley near Lamon’s winter cabin, I heard a distinct bubbling thunder from the direction of Tenaya Cañon Carlo, a large intelligent St. Bernard dog standing beside me seemed greatly astonished, and looked intently in that direction with mouth open and uttered a low Wouf! as if saying, “What’s that?” He must have known that it was not thunder, though like it. The air was perfectly still, not the faintest breath of wind perceptible, and a fine, mellow, sunny hush pervaded everything, in the midst of which came that subterranean thunder. Then, while we gazed and listened, came the corresponding shocks, distinct as if some mighty hand had shaken the ground. After the sharp horizontal jars died away, they were followed by a gentle rocking and undulating of the ground so distinct that Carlo looked at the log on which he was standing to see who was shaking it. It was the season of flooded meadows and the pools about me, calm as sheets of glass, were suddenly thrown into low ruffling waves.
Judging by its effects, this Yosemite, or Inyo earthquake, as it is sometimes called, was gentle as compared with the one that gave rise to the grand talus system of the Range and did so much for the cañon scenery. Nature, usually so deliberate in her operations, then created, as we have seen, a new set of features, simply by giving the mountains a shake—changing not only the high peaks and cliffs, but the streams. As soon as these rock avalanches fell the streams began to sing new songs; for in many places thousands of boulders were hurled into their channels, roughening and half-damming them, compelling the waters to surge and roar in rapids where before they glided smoothly. Some of the streams were completely dammed; driftwood, leaves, etc., gradually filling the interstices between the boulders, thus giving rise to lakes and level reaches; and these again, after being gradually filled in, were changed to meadows, through which the streams are now silently meandering; while at the same time some of the taluses took the places of old meadows and groves. Thus rough places were made smooth, and smooth places rough. But, on the whole, by what at first sight seemed pure confounded confusion and ruin, the landscapes were enriched; for gradually every talus was covered with groves and gardens, and made a finely proportioned and ornamental base for the cliffs. In this work of beauty, every boulder is prepared and measured and put in its place more thoughtfully than are the stones of temples. If for a moment you are inclined to regard these taluses as mere draggled, chaotic dumps, climb to the top of one of them, and run down without any haggling, puttering hesitation, boldly jumping from boulder to boulder with even speed. You will then find your feet playing a tune, and quickly discover the music and poetry of these magnificent rock piles—a fine lesson; and all Nature’s wildness tells the same story—the shocks and outbursts of earthquakes, volcanoes, geysers, roaring, thundering waves and floods, the silent uprush of sap in plants, storms of every sort—each and all are the orderly beauty-making love-beats of Nature’s heart.
Chapter 5
The Trees of the Valley
The most influential of the Valley trees is the yellow pine (Pinus ponderosa). It attains its noblest dimensions on beds of water-washed, coarsely-stratified moraine material, between the talus slopes and meadows, dry on the surface, well-watered below and where not too closely assembled in groves the branches reach nearly to the ground, forming grand spires 200 to 220 feet in height. The largest that I have measured is standing alone almost opposite the Sentinel Rock, or a little to the westward of it. It is a little over eight feet in diameter and about 220 feet high. Climbing these grand trees, especially when they are waving and singing in worship in wind-storms, is a glorious experience. Ascending from the lowest branch to the topmost is like stepping up stairs through a blaze of white light, every needle thrilling and shining as if with religious ecstasy.
Unfortunately there are but few sugar pines in the Valley, though in the King’s yosemite they are in glorious abundance. The incense cedar (Libocedrus decurrens) with cinnamon-colored bark and yellow-green foliage is one of the most interesting of the Yosemite trees. Some of them are 150 feet high, from six to ten feet in diameter, and they are never out of sight as you saunter among the yellow pines. Their bright brown shafts and towers of flat, frondlike branches make a striking feature of the landscapes throughout all the seasons. In midwinter, when most of the other trees are asleep, this cedar puts forth its flowers in millions,—the pistillate pale green and inconspicuous, but the staminate bright yellow, tingeing all the branches and making the trees as they stand in the snow look like gigantic goldenrods. The branches, outspread in flat plumes and, beautifully fronded, sweep gracefully downward and outward, except those near the top, which aspire; the lowest, especially in youth and middle age, droop to the ground, overlapping one another, shedding off rain and snow like shingles, and making fine tents for birds and campers. This tree frequently lives more than a thousand years and is well worthy its place beside the great pines and the Douglas spruce.
The two largest specimens I know of the Douglas spruce, about eight feet in diameter, are growing at the foot of the Liberty Cap near the Nevada Fall, and on the terminal moraine of the small residual glacier that lingered in the shady Illilouette Cañon.
After the conifers, the most important of the Yosemite trees are the oaks, two species; the California live-oak (Quercus agrifolia), with black trunks, reaching a thickness of from four to nearly seven feet, wide spreading branches and bright deeply-scalloped leaves. It occupies the greater part of the broad sandy flats of the upper end of the Valley, and is the species that yields the acorns so highly prized by the Indians and woodpeckers.
The other species is the mountain live-oak, or goldcup oak (Quercus chrysolepis), a sturdy mountaineer of a tree, growing mostly on the earthquake taluses and benches of the sunny north wall of the Valley. In tough, unwedgeable, knotty strength, it is the oak of oaks, a magnificent tree.
The largest and most picturesque specimen in the Valley is near the foot of the Tenaya Fall, a romantic spot seldom seen on account of the rough trouble of getting to it. It is planted on three huge boulders and yet manages to draw sufficient moisture and food from this craggy soil to maintain itself in good health. It is twenty feet in circumference, measured above a large branch between three and four feet in diameter that has been broken off. The main knotty trunk seems to be made up of craggy granite boulders like those on which it stands, being about the same color as the mossy, lichened boulders and about as rough. Two moss-lined caves near the ground open back into the trunk, one on the north side, the other on the west, forming picturesque, romantic seats. The largest of the main branches is eighteen feet and nine inches in circumference, and some of the long pendulous branchlets droop over the stream at the foot of the fall where it is gray with spray. The leaves are glossy yellow-green, ever in motion from the wind from the fall. It is a fine place to dream in, with falls, cascades, cool rocks lined with hypnum three inches thick; shaded with maple, dogwood, alder, willow; grand clumps of lady-ferns where no hand may touch them; light filtering through translucent leaves; oaks fifty feet high; lilies eight feet high in a filled lake basin near by, and the finest libocedrus groves and tallest ferns and goldenrods.
In the main river cañon below the Vernal Fall and on the shady south side of the Valley there are a few groves of the silver fir (Abies concolor), and superb forests of the magnificent species round the rim of the Valley.
On the tops of the domes is found the sturdy, storm-enduring red cedar (Juniperus occidentalis). It never makes anything like a forest here, but stands out separate and independent in the wind, clinging by slight joints to the rock, with scarce a handful of soil in sight of it, seeming to depend chiefly on snow and air for nourishment, and yet it has maintained tough health on this diet for two thousand years or more. The largest hereabouts are from five to six feet in diameter and fifty feet in height.
The principal river-side trees are poplar, alder, willow, broad-leaved maple, and Nuttall’s flowering dogwood. The poplar (Populus trichocarpa), often called balm-of-Gilead from the gum on its buds, is a tall tree, towering above its companions and gracefully embowering the banks of the river. Its abundant foliage turns bright yellow in the fall, and the Indian-summer sunshine sifts through it in delightful tones over the slow-gliding waters when they are at their lowest ebb.
Some of the involucres of the flowering dogwood measure six to eight inches in diameter, and the whole tree when in flower looks as if covered with snow. In the spring when the streams are in flood it is the whitest of trees. In Indian summer the leaves become bright crimson, making a still grander show than the flowers.
The broad-leaved maple and mountain maple are found mostly in the cool cañons at the head of the Valley, spreading their branches in beautiful arches over the foaming streams.
Scattered here and there are a few other trees, mostly small—the mountain mahogany, cherry, chestnut-oak, and laurel. The California nutmeg (Torreya californica), a handsome evergreen belonging to the yew family, forms small groves near the cascades a mile or two below the foot of the Valley.
Chapter 6
The Forest Trees in General
For the use of the ever-increasing number of Yosemite visitors who make extensive excursions into the mountains beyond the Valley, a sketch of the forest trees in general will probably be found useful. The different species are arranged in zones and sections, which brings the forest as a whole within the comprehension of every observer. These species are always found as controlled by the climates of different elevations, by soil and by the comparative strength of each species in taking and holding possession of the ground; and so appreciable are these relations the traveler need never be at a loss in determining within a few hundred feet his elevation above sea level by the trees alone; for, notwithstanding some of the species range upward for several thousand feet and all pass one another more or less, yet even those species possessing the greatest vertical range are available in measuring the elevation; inasmuch as they take on new forms corresponding with variations in altitude. Entering the lower fringe of the forest composed of Douglas oaks and Sabine pines, the trees grow so far apart that not one-twentieth of the surface of the ground is in shade at noon. After advancing fifteen or twenty miles towards Yosemite and making an ascent of from two to three thousand feet you reach the lower margin of the main pine belt, composed of great sugar pine, yellow pine, incense cedar and sequoia. Next you come to the magnificent silver-fir belt and lastly to the upper pine belt, which sweep up to the feet of the summit peaks in a dwarfed fringe, to a height of from ten to twelve thousand feet. That this general order of distribution depends on climate as affected by height above the sea, is seen at once, but there are other harmonies that become manifest only after observation and study. One of the most interesting of these is the arrangement of the forest in long curving bands, braided together into lace-like patterns in some places and out-spread in charming variety. The key to these striking arrangements is the system of ancient glaciers; where they flowed the trees followed, tracing their courses along the sides of cañons, over ridges, and high plateaus. The cedar of Lebanon, said Sir Joseph Hooker, occurs upon one of the moraines of an ancient glacier. All the forests of the Sierra are growing upon moraines, but moraines vanish like the glaciers that make them. Every storm that falls upon them wastes them, carrying away their decaying, disintegrating material into new formations, until they are no longer recognizable without tracing their transitional forms down the Range from those still in process of formation in some places through those that are more and more ancient and more obscured by vegetation and all kinds of post-glacial weathering. It appears, therefore, that the Sierra forests indicate the extent and positions of ancient moraines as well as they do belts of climate.
One will have no difficulty in knowing the Nut Pine (Pinus Sabiniana), for it is the first conifer met in ascending the Range from the west, springing up here and there among Douglas oaks and thickets of ceanothus and manzanita; its extreme upper limit being about 4000 feet above the sea, its lower about from 500 to 800 feet. It is remarkable for its loose, airy, wide-branching habit and thin gray foliage. Full-grown specimens are from forty to fifty feet in height and from two to three feet in diameter. The trunk usually divides into three or four main branches about fifteen or twenty feet from the ground that, after bearing away from one another, shoot straight up and form separate summits. Their slender, grayish needles are from eight to twelve inches long, and inclined to droop, contrasting with the rigid, dark-colored trunk and branches. No other tree of my acquaintance so substantial in its body has foliage so thin and pervious to the light. The cones are from five to eight inches long and about as large in thickness; rich chocolate-brown in color and protected by strong, down-curving nooks which terminate the scales. Nevertheless the little Douglas Squirrel can open them. Indians climb the trees like bears and beat off the cones or recklessly cut off the more fruitful branches with hatchets, while the squaws gather and roast them until the scales open sufficiently to allow the hard-shell seeds to be beaten out. The curious little Pinus attenuata is found at an elevation of from 1500 to 3000 feet, growing in close groves and belts. It is exceedingly slender and graceful, although trees that chance to stand alone send out very long, curved branches, making a striking contrast to the ordinary grove form. The foliage is of the same peculiar gray-green color as that of the nut pine, and is worn about as loosely, so that the body of the tree is scarcely obscured by it. At the age of seven or eight years it begins to bear cones in whorls on the main axis, and as they never fall off, the trunk is soon picturesquely dotted with them. Branches also soon become fruitful. The average size of the tree is about thirty or forty feet in height and twelve to fourteen inches in diameter. The cones are about four inches long and covered with a sort of varnish and gum, rendering them impervious to moisture.
No observer can fail to notice the admirable adaptation of this curious pine to the fire-swept regions where alone it is found. After a running fire has scorched and killed it the cones open and the ground beneath it is then sown broadcast with all the seeds ripened during its whole life. Then up spring a crowd of bright, hopeful seedlings, giving beauty for ashes in lavish abundance.