Part 6 (1/2)
The inviting openness of the Sierra woods is one of their most distinguis.h.i.+ng characteristics. The trees of all the species stand more or less apart in groves, or in small, irregular groups, enabling one to find a way nearly everywhere, along sunny colonnades and through openings that have a smooth, park-like surface, strewn with brown needles and burs. Now you cross a wild garden, now a meadow, now a ferny, willowy stream; and ever and anon you emerge from all the groves and flowers upon some granite pavement or high, bare ridge commanding superb views above the waving sea of evergreens far and near.
One would experience but little difficulty in riding on horseback through the successive belts all the way up to the storm-beaten fringes of the icy peaks. The deep canons, however, that extend from the axis of the range, cut the belts more or less completely into sections, and prevent the mounted traveler from tracing them lengthwise.
This simple arrangement in zones and sections brings the forest, as a whole, within the comprehension of every observer. The different species are ever found occupying the same relative positions to one another, as controlled by soil, climate, and the comparative vigor of each species in taking and holding the ground; and so appreciable are these relations, one need never be at a loss in determining, within a few hundred feet, the elevation above sea-level by the trees alone; for, notwithstanding some of the species range upward for several thousand feet, and all pa.s.s one another more or less, yet even those possessing the greatest vertical range are available in this connection, in as much as they take on new forms corresponding with the variations in alt.i.tude.
Crossing the treeless plains of the Sacramento and San Joaquin from the west and reaching the Sierra foot-hills, you enter the lower fringe of the forest, composed of small oaks and pines, growing so far apart that not one twentieth of the surface of the ground is in shade at clear noonday. After advancing fifteen or twenty miles, and making an ascent of from two to three thousand feet, you reach the lower margin of the main pine belt, composed of the gigantic 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 sweeps up the rocky acclivities of the summit peaks in a dwarfed, wavering fringe to a height of from ten to twelve thousand feet.
[Ill.u.s.tration: EDGE OF THE TIMBER LINE ON MOUNT SHASTA.]
This general order of distribution, with reference to climate dependent on elevation, is perceived at once, but there are other harmonies, as far-reaching in this connection, that become manifest only after patient observation and study. Perhaps the most interesting of these is the arrangement of the forests in long, curving bands, braided together into lace-like patterns, and outspread in charming variety. The key to this beautiful harmony is the ancient glaciers; where they flowed the trees followed, tracing their wavering courses along canons, over ridges, and over high, rolling plateaus. The Cedars of Lebanon, says Hooker, are growing 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, cutting gaps, disintegrating boulders, and carrying away their decaying material into new formations, until at length they are no longer recognizable by any save students, who trace their transitional forms down from the fresh moraines still in process of formation, through those that are more and more ancient, and more and more obscured by vegetation and all kinds of post-glacial weathering.
Had the ice-sheet that once covered all the range been melted simultaneously from the foot-hills to the summits, the flanks would, of course, have been left almost bare of soil, and these n.o.ble forests would be wanting. Many groves and thickets would undoubtedly have grown up on lake and avalanche beds, and many a fair flower and shrub would have found food and a dwelling-place in weathered nooks and crevices, but the Sierra as a whole would have been a bare, rocky desert.
[Ill.u.s.tration: VIEW IN THE MAIN PINE BELT OF THE SIERRA FOREST.]
It appears, therefore, that the Sierra forests in general indicate the extent and positions of the ancient moraines as well as they do lines of climate. For forests, properly speaking, cannot exist without soil; and, since the moraines have been deposited upon the solid rock, and only upon elected places, leaving a considerable portion of the old glacial surface bare, we find luxuriant forests of pine and fir abruptly terminated by scored and polished pavements on which not even a moss is growing, though soil alone is required to fit them for the growth of trees 200 feet in height.
THE NUT PINE (_Pinus Sabiniana_)
The Nut Pine, the first conifer met in ascending the range from the west, grows only on the torrid foothills, seeming to delight in the most ardent sun-heat, like a palm; springing up here and there singly, or in scattered groups of five or six, among scrubby White 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.
This tree is remarkable for its airy, widespread, tropical appearance, which suggests a region of palms, rather than cool, resiny pine woods.
No one would take it at first sight to be a conifer of any kind, it is so loose in habit and so widely branched, and its foliage is so thin and gray. 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 and twenty feet from the ground, which, after bearing away from one another, shoot straight up and form separate summits; while the crooked subordinate branches aspire, and radiate, and droop in ornamental sprays. The slender, grayish-green needles are from eight to twelve inches long, loosely ta.s.seled, and inclined to droop in handsome curves, contrasting with the stiff, dark-colored trunk and branches in a very striking manner. No other tree of my acquaintance, so substantial in body, is in its foliage so thin and so pervious to the light. The sunbeams sift through even the leafiest trees with scarcely any interruption, and the weary, heated traveler finds but little protection in their shade.
[Ill.u.s.tration: NUT PINE (PINUS SABINIANA).]
The generous crop of nutritious nuts which the Nut Pine yields makes it a favorite with Indians, bears, and squirrels. The cones are most beautiful, measuring from five to eight inches in length, and not much less in thickness, rich chocolate-brown in color, and protected by strong, down-curving hooks Which terminate the scales. Nevertheless, the little Douglas squirrel can open them. Indians gathering the ripe nuts make a striking picture. The men climb the trees like bears and beat off the cones with sticks, or recklessly cut off the more fruitful branches with hatchets, while the squaws gather the big, generous cones, and roast them until the scales open sufficiently to allow the hard-sh.e.l.led seeds to be beaten out. Then, in the cool evenings, men, women, and children, with their capacity for dirt greatly increased by the soft resin with which they are all bedraggled, form circles around camp-fires, on the bank of the nearest stream, and lie in easy independence cracking nuts and laughing and chattering, as heedless of the future as the squirrels.
_Pinus tuberculata_
This curious little pine is found at an elevation of from 1500 to 3000 feet, growing in close, willowy groves. It is exceedingly slender and graceful in habit, although trees that chance to stand alone outside the groves sweep forth long, curved branches, producing 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.
[Ill.u.s.tration: THE GROVE FORM. THE ISOLATED FORM (PINUS TUBERCULATA).]
At the age of seven or eight years it begins to bear cones, not on branches, but on the main axis, and, as they never fall off, the trunk is soon picturesquely dotted with them. The branches also become fruitful after they attain sufficient size. The average size of the older trees is about thirty or forty feet in height, and twelve to fourteen inches in diameter. The cones are about four inches long, exceedingly hard, and covered with a sort of silicious varnish and gum, rendering them impervious to moisture, evidently with a view to the careful preservation of the seeds.
No other conifer in the range is so closely restricted to special localities. It is usually found apart, standing deep in chaparral on sunny hill-and canon-sides where there is but little depth of soil, and, where found at all, it is quite plentiful; but the ordinary traveler, following carriage-roads and trails, may ascend the range many times without meeting it.
While exploring the lower portion of the Merced Canon I found a lonely miner seeking his fortune in a quartz vein on a wild mountain-side planted with this singular tree. He told me that he called it the Hickory Pine, because of the whiteness and toughness of the wood. It is so little known, however, that it can hardly be said to have a common name. Most mountaineers refer to it as ”that queer little pine-tree covered all over with burs.” In my studies of this species I found a very interesting and significant group of facts, whose relations will be seen almost as soon as stated:
1st. All the trees in the groves I examined, however unequal in size, are of the same age.
2d. Those groves are all planted on dry hillsides covered with chaparral, and therefore are liable to be swept by fire.
3d. There are no seedlings or saplings in or about the living groves, but there is always a fine, hopeful crop springing up on the ground once occupied by any grove that has been destroyed by the burning of the chaparral.
4th. The cones never fall off and never discharge their seeds until the tree or branch to which they belong dies.
[Ill.u.s.tration: LOWER MARGIN OF THE MAIN PINE BELT, SHOWING OPEN CHARACTER OF WOODS.]