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THE JUNIPERS OF LAKE VALLEY
By CORNELIUS BEACH BRADLEY
NE day last summer, while driving through Lake Valley
at the upper end of Lake Tahoe, I was surprised to see among the yellow pines and tamaracks of the open forest certain trees that seemed to me new. I thought that I knew all the trees in that part of the Sierra. My companion pronounced them tamaracks (Pinus contorta var. murrayana), which indeed they greatly resembled in stature and in habit. But the tawny-gray fibrous bark and the finer sprays of foliage convinced me that they could not be that. On examination at a later time we found that they were junipers, but so unlike the forms of Juniperus occidentalis with which we were familiar that we were compelled to suppose them to be of a different species-possibly one that had worked its way over from the eastern side of the range through Luther's Pass. But on my return to Berkeley the specimens of foliage and fruit which I had brought with me were identified by Dr. H. M. Hall as undoubtedly those of J. occidentalis.
The features of these trees which had puzzled me were: (1) their unusual situation on the floor of a deep sheltered valley, instead of on the exposed rocky slopes of the Sierra ridges; (2) their close association with other conifers instead of being scattered about singly in the open; (3) their stature, reaching eighty or ninety feet-twice or thrice that of the tree in its usual habitat; (4) their symmetrical shape and aspiring habit which here persist even to old age. For, while this feature is common throughout the whole group of cypress-like trees, and regularly appears in the early life of this species, it is lost long before maturity by those individuals which face the Sierra storms unprotected.*
Another feature which impressed us later was the frequent occurrence in this group of the twin or double tree, as seen in plates CCII and CCIV. This also occurs, but I think not so frequently, among junipers which grow on the exposed mountain ridges. The double tree might in reality be a single one which forked very early in life because of the loss of its leading shoot; or it might be two trees which, germinating near each other, grew at length large enough to touch and then to mingle into one common trunk. But why should this be more common among these junipers than among the yellow pines and tamaracks about them? Here surely is an interesting problem for some one to solve. ·
* See plates CC and CCI.
Here then was a group of some hundreds of these trees scattered about among the pines of the valley floor between Myers' station and the forest-ranger's cabin some two miles to the south. They seemed moreover to be strictly confined to this area. None were found either to the north or to the south of it. Right through the center of it runs the automobile road to Luther's Pass and Markleeville. Hundreds of campers and tourists pass through it every season. Yet it seems never to have come to the notice of our botanists. Indeed Dr. W. L. Jepson tells me that he has never known of such a group of these trees, although he has known of exceptional individuals of their stature and habit.
The special characters of this group are due no doubt to the richer soil in which they grow, and to the protection against storms afforded both by the high ridges east and west of them and by the other forest trees growing about them. Since similar conditions are by no means uncommon in the Sierra at this altitude, it seems altogether likely that such groups might be found elsewhere, if people were only on the lookout for them. I I hope that members of the Sierra Club and other persons interested in such things will, on their summer rambles, keep this matter in mind, and especially that they will not fail to report their findings.
The fact that a number of these trees had recently been cut to furnish posts for some miles of fencing on the road to Tallac, led me to take up the question of their age. The trees
† In his monumental Silz'a of California (1910) the only notice of this exceptional type is the following sentence: “In protected localities they present regular figures forty to sixty-five feet high, and sometimes six or seven feet in diameter."
Since writing the above I have learned of the existence of a somewhat similar group on the South Yuba, between Cisco and the Summit.
felled for this purpose were all vigorous and clean-growing junipers in their young prime, from two to three feet in diameter, and from sixty to seventy feet high. From my notes I select the following typical counts of the annual rings of growth.
No. 1. Prostrate trunk, one of the two trunks of a double tree. Section at 10 feet from the ground. Diameter 24 inches, 247 rings.
No. 2. Stump. Section at three feet from the ground. Diameters 27 and 36 inches, 236 rings.
No. 3. Prostrate half of a double tree which had stood 70 feet high. Diameter at 10 feet above the ground, 28 inches, 255 rings.
No. 4. A fine double tree, still in vigorous growth; each trunk nearly five feet in diameter, and the combined trunk nearly nine feet. A superficial cut to a depth of 1/8 inches showed 40 layers of growth.
In order to bring these results to bear upon the question of the age of junipers growing under conditions which are for them more usual than those of Lake Valley, we later cut down a vigorous young tree growing on a rocky ledge in Glen Alpine, near Lily Lake, and brought a section of the trunk to Berkeley, where it is now in the Herbarium of the University. This tree is
No. 5. Diameters, 14 and 18 inches. Rings, 230.8
This last tree from the mountain side proved to be a very instructive parallel to those selected as typical of growth on the valley floor. For while the age was nearly the same throughout the whole group, the measured diameters of the valley trees averaged nearly twice as great as that of the mountain tree. All this was interesting and suggestive, but it did not go far enough. We need to know also the age of the much larger trees which are frequently encountered—from five to seven feet, as stated in the Silva; and trees considerably larger than that have been credibly reported. Direct and conclusive answer to this question can, of course, be had only by felling
$ The upper surface was chosen for measurement because it was clear of the swell about the roots. The count of rings could not be made on this surface because of a cavity at the heart. It was therefore made on the lower surface, and showed 234 rings. An allowance of 4 rings was then made for the difference of 13 inches in height.