BIGTREE
(Sequoia Washingtoniana)

Botanists have had a hard time giving this tree a Latin name which will meet the requirements of technical classification, but an English name acceptable everywhere was early found for it—bigtree. No fewer than a dozen names have been proposed by botanists. Most of them attempt to express the idea of vastness or grandeur; but the simple English name comes directly to the point and ends the controversy as far as the common name is concerned.

Everything connected with this tree is interesting. Geologically, it is as old as the yellow poplar. There were five species of sequoias in the northern hemisphere, in Europe and America, before the ice age. They grew in the North, nearly to the Arctic circle, at a time when the climate of those regions was milder than it is now. The later advance of the ice southward overwhelmed three species of bigtrees, and pushed two survivors into the region which is now California. These are the bigtree and the redwood. It is not known how long ago it was that the ice sheet did its destructive work, but it antedated human history, and the gigantic trees have been in California since that time.

Long after the ice age ceased generally in North America it continued among the high Sierras of California, and the bigtrees to this day give a hint of it in the peculiar outlines of their range. They are scattered north and south along the face of the Sierra Nevada mountains in California, a distance of 260 miles, and at elevations from 4,500 to 8,000 feet.

The aggregate of the total areas is about fifty square miles. The stand is not continuous, but consists of “groves,” that is, isolated stands with wide intervals between, where no trees of this species are found. The arrangement suggests that the bigtree forest was cut in sections by glaciers which descended from the high mountains to the plains, a distance of one hundred miles or more, crossing the belt of sequoias at right angles. The glaciers withdrew thousands of years ago, and their tracks down the mountain slopes have long been covered by forests; but the bigtree groves, for some unknown reason, never spread into the intervening spaces, but today are separated by wide tracts in which not a seedling or an old trunk or log of that species is to be found. This is one of the mysteries which add interest to those wonderful trees—why they cannot extend their range beyond the circumscribed limits which they occupied thousands of years ago.

It was claimed for a long time and was quite generally believed that bigtrees were not reproducing, that there “were no little bigtrees.” That was conclusively disproved by Fred G. Plummer, geographer of the United States Forest Service, who made a scientific study of a small grove, measured the trees, and actually counted and classified them. His work showed that there were in the area which he investigated:

Bigtree is distantly related to southern cypress, and the shapes of very old trees of both species bear some resemblance. Bigtree leaves do not fall annually as those of bald cypress do. They are from one-eighth to one-fourth of an inch long, and on the leading shoots they may be half an inch in length. Cones are from two to three and a half inches long, and they ripen their seeds the second year, but the empty cones may adhere to the branches several years. The seeds are a quarter of an inch long, and have wings sufficient to carry them a hundred yards or more. The trees bear abundance of seeds, in proportion to the small number of branches. Though shapely and well clothed with limbs when young, the crown contracts with age, and consists of a few enormous, crooked limbs, almost destitute of twigs and small branches. One of these trees may actually bear more twigs when the trunk is only a foot in diameter than will be on the same trunk when it is fifteen or twenty feet in diameter. The old tree trunks are often without limbs to a height of 100 or 150 feet.

The Douglas squirrel is the bigtree’s greatest enemy. In proportion to size, this little creature probably eats ten times as many tree seeds as the most ravenous hog that roams the forest. One of the first things that impresses a visitor in a grove of bigtrees is the rich brown of the bark of some of the trunks. All are not brown alike, or at all seasons. The trees on which the seed harvest is ready are the brownest, thanks to the sharp claws, the tireless energy, and keen appetite of the Douglas squirrel. He goes up and down the trunks for three square meals a day among the clusters of cone-bearing branches two hundred or three hundred feet above, and makes several extra trips for exercise; and at each scratch of his briery foot he kicks off scales of bark, until the whole trunk is “scratched raw.” The detached scales of bark accumulate in a mound about the base of the tree, where they have been so accumulating for centuries. It is fortunate that those old trees have bark from one to two feet thick. They can afford to be scratched for a month or two each year.

These are the heaviest trees in America, notwithstanding their wood is light. It weighs less than northern white cedar. The largest bigtree trunks weigh more than 2,000,000 pounds. In order to stand at all, they must stand plumb. It is a provision of nature that the old trees are almost branchless, otherwise the wind would force them out of plumb and they would go down. It has been claimed that the overthrow of one of these giants is always brought about by one of two causes. The development of larger limbs on one side than on another unbalances them; or the wash of gullies undermines the roots on one side, and draws the tree that way. It is currently believed that no bigtree ever dies from natural causes.

A good deal of pure fiction has been published regarding the size and age of the largest of these trees. They are old enough and large enough without drawing upon the imagination. The tree’s base is greatly enlarged, but tapers rapidly the first few feet. There is little doubt that some of the trunks are over forty feet in diameter, one foot above ground, but that is not a fair measurement. The point should be five or six feet at least. Measured thus, about twenty-five feet inside the bark would represent the largest. With the bark added, the diameter would be nearly thirty feet. Probably not one tree in fifty, taking them as they occur in the whole range and counting veterans only, is fifteen feet in diameter five feet from the ground.

There is also some extravagant guessing as to height. Too many tourists measure with the unaided eye, or accept a guidebook’s figures. An authentic height of 365 feet—the measurement of a fallen trunk—is probably the greatest. Very few reach three hundred feet. Many unreliable figures have been published concerning the age of bigtrees. One thing can be accepted without question; size is no proof of age, in comparing one tree with another; neither is the number of annual rings in a block cut from the side of a tree a reliable factor to determine age. The only sure way to determine the age of one of these trees is by counting all the rings from the pith to bark. Care should be taken not to count the same ring twice, as may be done when the wood is curly. John Muir counted 4,000 rings in a bigtree stump. It is believed that no higher age is backed by the evidence of yearly rings. It was twenty-four feet in diameter. The count of another of like size made it 2,200 years old; and of still another of the same size placed its age at 1,300 years. The Forest Service has made accurate measurement and record of every ring of growth in a tree that was over twenty-four feet in diameter, and it is shown that during certain periods of years the tree grew three or four times as rapidly as during other periods.

The wood of bigtree is very light, soft, moderately strong, brittle, summerwood thin and dark rendering the rings of annual growth easily seen; the medullary rays are thin, numerous, and very obscure. The wood is light to dark red, the thin sapwood nearly white; it works easily, splits readily, and polishes well. It is very durable in contact with the soil. Trunks lie in the woods long periods before decay seriously attacks them; but forest fires hollow them, and finally burn them up. Enormous depressions are found in the forest where logs once lay, but which disappeared long ago, judging by the size of trees which have since grown in the depressions. The interior of some large trunks which have been worked up on sawmills showed the scars of forest fires centuries ago. The annual rings which covered one such scar showed that the burning took place 1,700 years ago.

Not much can be said for the commercial uses of bigtree. Many a species of insignificant size is much more useful. Considerable quantities have been cut by sawmills. The waste is great, heavy trunks crushing badly in fall. Logs are so large that many of them are split with gunpowder to facilitate handling them. Some of the wood has been exported for lead pencils; other has been used for fence posts, shingles, and grapevine stakes, while the soft bark has been worked into novelties.