Page:Climatic Cycles and Tree-Growth - 1919.djvu/58

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46
CLIMATIC CYCLES AND TREE-GROWTH.

delightfully mild summers. The latter have occasional thunder-storms whose waters quickly run down the mountain slope. Thus conservation plays an important part in the growth of these trees by rendering the winter precipitation more important than the summer and by permitting the moisture to remain long in the swampy places.

Three groups were obtained from this general region in 1915. The first of these came from the uplands above Camp 6 close to the west line of section 17, township 13 south, range 29 east. This region may be found on the Tehipite Quadrangle of the United States Geological Survey. The group includes Nos. 1 to 5. No. 1 was a splendid tree, about 19 feet in its greatest diameter, growing at the uppermost limit of the logging area. Its growth was rapid, and yet it was an extremely sensitive tree, showing beautiful variations from year to year. No. 2 was obtained a Uttle lower down and is mentioned here because it has been used as the standard of the whole sequoia group, having probably a more perfect record than any other tree measured. Its center was about 300 B. C. No. 5 was a small tree which was cut just at the time I came within hearing distance. I thought that two blasts of dynamite were set off and found afterwards that only one charge of dynamite had been used to break through the last support of the mighty tree; the other report was the tree itself crashing to the ground. Yet this was a small tree, only some 12 feet in diameter, and its age was about 700 years. It proved of particular value to the whole sequoia group, because it was the only tree on which was obtained the ring of the current year, thus permitting a very important correction to be made in the dating of rings. This had an important bearing on the relationship of rings to rainfall.

The second group included Nos. 6 to 11, and was made about a mile to the north and 700 feet lower altitude in the swampy basin whose outlet was similarly toward the northeast. No. 6 grew at the edge of the little brook running through the basin and its rings proved later very uncertain in identity, because its habit was complacent, i. e., the rings were nearly all alike in size.[1] No. 7 was an improvement on it, and No. 8, which was still farther from the creek, was perhaps the best of this group of 6. It gave a very fine cross-identification with the first group. No. 11 was also very close to the creek near the outlet of the basin and, as with No. 6, it was impossible to be sure of the identification, owing to its complacent character.

The third group consisted of 4 trees from Indian Basin, about 10 miles northwest of the Redwood Basin and 3 miles north of Hume. This basin is a broad, flat, fertile area with an outlet toward the northeast. Four trees were obtained there which Huntington had already counted. Nos. 12 and 13 came from the flat middle area of the basin. No. 12 was not included in the final averaging because its rings

  1. Since the trip of 1919 the identificaticn of No. 6 has been fully established.