VI. TREE RECORDS: LENGTH 



The first definite purpose in making the collections here described 

 was the extension and improvement of the 3,000-year sequoia records 

 presented in the previous volume. This was followed by a similar 

 plan in regard to the yellow pine as soon as certain probabilities 

 of extension were realized. The present chapter deals with these 

 attempts. As the number of specimens grew and material came from 

 many sources, the study of local and continental topographic effects 

 took shape and has become a central theme of this volume, as indi- 

 cated in the succeeding chapters (VII and VIII). Finally, large 

 quantities of early historic, prehistoric, and geologic material came 

 to the laboratory and the problem was presented of reconstructing, 

 in part at least, the climates of past ages by such indications as could 

 be found in tree-rings. Hence arose the thought of collecting and 

 formulating climatic indicators in trees (VIII). All this is of funda- 

 mental importance in the continued investigation of climatic cycles 

 and tree-growth (IX). 



OLD SEQUOIA RECORDS 

 THIRD SEQUOIA TRIP, 1919 



The trip to the groves near General Grant Park in July 1919 was 

 made for the purpose of determining the status of a certain ring called 

 1580 A, which was in doubt because it had appeared in less than half 

 of the 23 specimens at that time in hand. It was also planned to make 

 a topographic study of the influence of the immediate environment, 

 especially ground-water, on ring-growth. After a trip to Wigger's, 

 just south of the Park, to see an immense stump, and after an examina- 

 tion of the General Grant tree to estimate its age, I went to Hume and 

 on the 12th accompanied a guide to the farthest parts of Camp 6, 

 where Nos. 1 to 5 had been collected, and selected new specimens for 

 cutting. The next day, with burros and a helper, camp was made at 

 the mouth of Redwood Basin, near the spring. With no one to help, the 

 radial pieces cut here the next morning were not on the scale previously 

 obtained. Instead of being 6 or 8 inches wide and deep, they were 

 about an inch in those dimensions. This meant their breaking into 

 many small pieces, which were immediately put into small marked bags. 

 The new specimens supplemented the 13 already obtained in that 

 district and gave opportunity of testing more thoroughly the relation 

 of sequoia growth to ground-water, which will be discussed in a later 

 chapter. 



The next day we cut a new radial from D-12 in Indian Basin, 

 which had previously failed to give a satisfactory dating on account 



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