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. 
54 
