Page:Climatic Cycles and Tree-Growth - 1919.djvu/62

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48
CLIMATIC CYCLES AND TREE-GROWTH.


provisionally. It was 700 years old, with coarse, sensitive rings, and was the only one of the group showing the ring for 1915. In comparing these two for larger variations no accordance was recognized and in details cross-identification failed also, due (as afterwards found) to accumulated errors in No. 1.

No. 2 was then counted and compared with No. 5 with apparent certainty and satisfaction. The former was nearly 6 feet in radius, with small rings, 2,200 years old, and with all but 3 years represented. The last 700 years were thus compared minutely with No. 5 and the earlier parts with No. 1, and one ring (later identified as 699 A. D.) was found to have been overlooked. The earlier parts were later all checked


Climatic Cycles and Tree-Growth Fig 12.jpg

Fig. 12.—Cross-identification in first five sequoias and gross rings in No. 1.

against No. 3 and no suspicion of error was discovered. This number was, therefore, taken as the best type of specimen of this group. Large fluctuations of size rarely occur in it.

No. 3 was next counted by comparison with No. 2. No. 3 has few large fluctuations and large portions of it match No. 2 with the greatest accuracy. Nevertheless, as a standard with which to compare others, it would be misleading, for it frequently omitted rings; in one place 7 rings and in another 6 rings are entirely missing, and half a dozen more in singles and in pairs. Yet cross-identification with No. 2 was easy and perfectly convincing as to the location of the missing rings.