So, I’ve been entering bearing tree data collected by land surveyors inside what is now Yosemite National Park, for work on estimating historic forest conditions in the Sierra Nevada. Bearing trees were designed to “bear witness” to the location of on-the-ground survey markers, in case something should happen to them, and several pieces of information on them were recorded in the field notes (previous post here). So up comes the next Township on the list: Township 2 South, Range 21 East, Mt. Diablo Meridian, or T2SR21E MDM in surveyors’ shorthand, an area now inside YNP, surveyed under authority of the General Land Office (GLO) in 1880, 10 years before YNP came into existence.
Well, damned if that isn’t a pretty good place to run into the man, Clarence King, and thereby to slow down the scientific progress on which society so utterly depends. Once I start reading King’s writings it’s all over in terms of getting things done. He’s done it to me before, and he will do it again.
King is partly responsible for the following survey plat map, which I’ll come back to in a second:
These tree data were not easy to come by, either originally or now. The surveys, especially in the mountains were a tremendous amount of work. Their databasing since then has been chaotic and scattered, mostly by various forest ecologists, beginning with Paul Sears for the state of Ohio, back in the 1920s. I photographed these data several years ago at the BLM Eastern States Field Office in Alexandria VA (the BLM is the successor of the GLO). That facility contains a fire-proof vault room containing a large fraction of the original General Land Office survey data from across the United States, going back to around 1800. I spent the better part of a couple weeks there, flipping pages and pressing down with one hand, and photographing them with the other. That was the quickest (and cheapest!) way to capture the data at the time. I’m just now getting around to databasing them for statistical analysis, which is pretty slow going.
Yosemite became a National Park in 1890, but well before that, in 1864, President Lincoln granted the Yosemite Valley and some land encircling it (along with the Mariposa Grove of giant sequoias), to the State of California. This was the first federal park land grant of any kind to a state, and foreshadowed events 8 years later, when a much larger chunk of ground was reserved by President Grant as Yellowstone National Park. King was charged by the State with surveying the boundary of the new grant, as he describes:
By an act of Congress the Yosemite Valley had been segregated from the public domain, and given—”donated,” as they call it—to the State of California, to be held inalienable for all time as a public pleasure-ground. The Commission into whose hands this trust devolved had sent Mr. Gardiner and myself to make a survey defining the boundaries of the new grant. It was necessary to execute this work before the Legislature should meet in December, and we undertook it, knowing very well that we must use the utmost haste in order to escape a three months’ imprisonment,—for in early winter the immense Sierra snow-falls would close the doors of mountain trails, and we should be unable to reach the lowlands until the following spring.
Now, if there’s anything that would be sure to incite King’s considerable abilities in wilderness mountain prose, it would be spending several weeks obtaining views of all the walls, from all angles, of Yosemite Valley just 13 years after its initial and accidental discovery by the Mariposa Batallion. And as usual, he doesn’t disappoint, beginning right from day one:
Gardiner, Cotter, and I felt thankful to our thermometer for owning up frankly the chill of the next morning, as we left a generous camp-fire and marched off through fir forest and among brown meadows and bare ridges of rock toward El Capitan. This grandest of granite precipices is capped by a sort of forehead of stone sweeping down to level, severe brows, which jut out a few feet over the edge. A few weather-beaten, battle-twisted, and black pines cling in clefts, contrasting in force with the solid white stone. We hung our barometer upon a stunted tree quite near the brink, and, climbing cautiously down, stretched ourselves out upon an overhanging block of granite, and looked over into the Yosemite Valley.
The rock fell under us in one sheer sweep of thirty-two hundred feet; upon its face we could trace the lines of fracture and all prominent lithological changes. Directly beneath, outspread like a delicately tinted chart, lay the lovely park of Yosemite, winding in and out about the solid white feet of precipices which sank into it on either side; its sunlit surface invaded by the shadow of the south wall; its spires of pine, open expanses of buff and drab meadow, and families of umber oaks rising as background for the vivid green river-margin and flaming orange masses of frosted cottonwood foliage…
And William Brewer, the Survey botanist and field leader, was perhaps rubbing off on him because he doesn’t disappoint with the forest descriptions either:
In returning to camp we followed a main ridge, smooth and white under foot, but shaded by groves of alpine firs [white fir, Abies concolor]. Trees which here reach mature stature, and in apparent health, stand rooted in white gravel, resulting from surface decomposition…Wherever, in deep depressions, enough wash soil and vegetable mould have accumulated, there the trees gather in thicker groups, lift themselves higher, spread out more and finer-feathered branches; sometimes, however, richness of soil and perfection of condition prove fatal through overcrowding. They are wonderfully like human communities.
They apparently started the survey just NW of El Capitan, marking the first survey corner location, Y.B.C. #1, with a sugar pine, returned to 16 years later by S.A. Hanson in his GLO survey of T2SR21E, because Hanson had to close (end) all his survey lines on the Yosemite Grant survey lines. That is, since the Yosemite Grant was no longer public domain land in 1880, there was no point in continuing the normal GLO rectangular land survey within its boundaries.
In the above image one sees the value “38.12”. This is the distance, in surveyor’s chains (66 ft, ~20 m) from where Hanson began his first survey line in the Township, to where it closes on the Yosemite Grant boundary. He chose two yellow (ponderosa) pine bearing trees, and records their diameter, distance and bearing from the corner, each falling within 58 links (= ~38 ft, 12 m), of the corner:
The first image shows that King and party had chosen a ponderosa pine tree as Y.B.C. #2, about 3.2 miles ENE of Y.B.C #1. I don’t have King’s original survey notes, but fifty years later, in 1914, a resurvey by the NPS showed that this tree was still alive, although with one side dead, 48 inches in diameter, and with three white fir and a sugar pine near it, which that surveyor established as new bearing trees. [Apparently King and co. did not establish any original bearing trees during their survey, since no mention is made of them in the resurvey, which they otherwise would have been.] The sugar pine at Y.B.C. #1 could not be found however, presumably having died. The surveyor also located the tree marking Y.B.C. #0, on the south side of Yosemite Valley, and established new bearing trees there. He had mixed success locating Hanson’s closing corners, i.e. where the 1880 and 1864 surveys joined.
Each page of field notes typically contains info on one to two corners, including the two to four bearing trees recorded at each. For example the page following that one contains two corners having six white fir BTs ranging from 15 to 60 inches diameter and from 12 to 42 links (~ 2.5 to 8.5 m) away. All the tree information is entered and used, for various purposes. The distances are needed in estimaing tree density (related posts here and here) and the bearings are useful in assessing tree selection biases, in the context of density estimation, as the distribution of angles should be uniform under unbiased tree selection. Similarly, the distribution of distances should be independent of either species or diameter. To keep it simple.
According to King, the entire circuit around the Valley took a few weeks. This was due in part to the need to triangulate certain lines, because of the steepness of the terrain. And not just from the Valley walls either but of the various stream courses that flow over them, such as Yosemite and Tenaya Creeks, and various granitic ridges and domes:
For a week the boundary survey was continued northeast and parallel to the cliff-wall, about a mile back from its brink, following through forests and crossing granite spurs until we reached the summit of that high, bare chain which divides the Virgin’s Tears from Yosemite Creek, and which, projecting southward, ends in the Three Brothers. East of this the declivity falls so rapidly to the valley of the upper Yosemite Creek that chaining was impossible, and we were obliged to throw our line across the cañon, a little over a mile, by triangulation. This completed, we resumed it on the North Dome spur…
And on it goes. Which is why I’m not getting much work done at the moment.
“One may trace in an hour’s walk nearly all the laws which govern the physical life of men”.
Clarence King, Around Yosemite Walls