IV. DETAILS OF CURVE PRODUCTION. 

 PREPARATION OF RADIAL SAMPLES. 



Form of sample. Nearly all of the 230 trees used in this investiga- 

 tion are represented by portions preserved in my collection. Wherever 

 possible the entire section, 1 to 3 inches or more in thickness, was 

 brought to the laboratory for examination. Unless the section was 

 light and easily handled, it was found convenient to cut from it a radial 

 piece showing the complete series of rings from center to bark. Natur- 

 ally the enormous trees of the sequoia groups could be obtained only 

 in radial form. The paper rubbings from Oregon and the small cuttings 

 of the Prescott and second Flagstaff groups were also of this type. 

 Hence the radial sample is regarded as the usual or type form in which 

 the material appears in the laboratory. If the original section was 

 small the radial piece appears as a bit of wood cut across the grain, 

 square or triangular in cross-section and a foot, more or less, in length. 



Method of Cutting. The partial radials, such as used in the Prescott 

 group, were secured from the stumps in place by making saw cuts at 

 the edge of the stump in two directions, meeting a few inches below the 

 surface. In this manner a piece of wood in the form of a triangular 

 pyramid was secured and was sent to the laboratory. The radials of 

 the sequoias were cut altogether from the tops of stumps or from the 

 ends of logs that lay on the ground. From the manner in which the 

 trees were cut down it was usually possible to get a clear surface of 

 stump or log from the bark on one side to somewhat past the center 

 where the under-cut had been made. After a minute examination of 

 the surface exposed, a radius was selected which would give the greatest 

 freedom from fire-scars and other irregularities of ring distribution. 

 Two lines about 8 inches apart were drawn with blue chalk along this 

 radius. Then two men with a saw 8 to 14 feet in length made a slanting 

 cut on one of the lines of sufficient depth and in the right direction to 

 meet a similar slanting cut from the other chalk line. In this way a 

 long piece of wood of V-shape in cross-section was obtained, extending 

 from the center to the outside and giving the full ring record. 



In sequoias recently felled this cutting of the radials was extremely 

 easy, but many of the sections obtained were from stumps which had 

 been standing and weathering for 25 years and in one case 43 years. 

 The exposure carbonizes the top of the stump and makes it extremely 

 brittle and difficult to cut; small pieces break off and wedge the saw. 

 Thus it often becomes a very difficult task to extract the radial section. 

 The pieces into which the radial section breaks are marked for identi- 

 fication immediately, photographed and listed in notebook, and then 

 carefully packed for shipment. On arriving at the laboratory, they 

 are pieced together with the greatest care and then glued together in 

 groups, making the entire radial section a series of convenient pieces 

 about 2 to 3 feet in length. 



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