INSTRUMENTS AND TECHNIQUE 35 



piece handle, which at the same time serves as carrying-case for the 

 cutting-tube, gives a strong purchase in turning the borer. When the 

 tree is bored as far as desired or practicable, a long, fine wedge is 

 thrust into the cutting-tube from the open end outside to hold the 

 core tightly in the cutting-tube while the borer is screwed out from 

 the tree. The first turn, of course, breaks the core away from the 

 tree and the core may be pulled out intact by the wedge. A difficulty 

 with this tool is the fact that in soft and watersoaked wood the outer 

 and softer layers are sometimes compressed and twisted. This is 

 usually negligible, but on one occasion in a dead sequoia the water- 

 soaked wood wedged in the borer so firmly that it had to be removed 

 by boring another tree and thus pushing out the wedged fragments 

 (boring in fallen sequoia at 215 feet from base of root, shown in part 

 in figs. 1 and 2). 



Core mounting — The cores usually come out intact, but gluing 

 pieces together is so satisfactory that breakage is no drawback. The 

 core is at once numbered in pencil every inch or two of its length, so 

 that its pieces may be identified if it breaks. It is then put in a paper 

 bag long enough to hold it and a full record made on the outside of the 

 bag. Other numbered cores and their records are added in the same 

 bag, as they help to keep each other from breaking. 



These cores are mounted on half-round strips of wood 12 inches 

 long and f inch wide. A shallow saw-cut is made lengthwise at the 

 rounded top, and this cut is rounded with a small round file so that the 

 core will he snugly in it. It is then glued with the bark end to the 

 right and about 1 inch from the end of the mount. The number is 

 placed at once on the mount at that end. In gluing, the vertical grain 

 of the tree is turned over into a horizontal position. This gives a 

 chance for just the right stroke with the razor blade in "shaving" the 

 surface so that the rings are brought out into the greatest prominence. 

 Identification and dating notes are placed on the wooden mount. 

 The various groups of these mounted specimens are tied in bundles and 

 filed in drawers of the proper width and depth. Such samples resist 

 very rough handling, last indefinitely in this form, and are always 

 ready for further study. 



Mr. Duncan Dunning, of the Forest Service office at San Francisco, 

 has made a temporary clamp of great convenience, in which the core 

 may be held while measures of its rings are made. Considering the 

 vast number of cores used by the Forest Service and the ease of 

 replacing lost or injured specimens, this temporary mounting is 

 extremely valuable. 



Borer extension — The 12-inch borer is the one commonly used, 

 giving a practical 10-inch core. A 10-inch borer was first tried and a 

 14-inch has been under examination, but seems too heavy. Very long 



