THE BILTMORE STICK AND ITS USE ON NATIONAL 



FORESTS. 



By a. G. Jackson. 



Every forester has felt the need of a simple and portable 

 diameter measure. Calipers, which are widely used and give 

 good results, are awkward instruments to carry in the timber. 

 They become coated with pitch, or swelled when used in the wet, 

 so their manipulation is difficult and unsatisfactory. The use of 

 calipers large enough to measure the trees of the Pacific coast 

 forest of Douglas fir, western red cedar and sugar pine, not to 

 mention the big sequoias, is impractical, to say the least. How- 

 ever, for use on trees in sample plots and wherever close accuracy 

 for individual trees is more important than speed or convenience, 

 calipers will always be in demand. For cruising and reconnais- 

 sance work their use will be limited to forests where the trees 

 are of a diameter permitting the use of small sized calipers. Even 

 in such forests a lighter and handier instrument will eventually 

 displace them. 



The diameter tape comes in for some use in measuring 

 occasional trees, especially those too large for the ordinary cal- 

 ipers, but it is too slow ever to be generally used in cruising, 

 Its results are usually too large due to its passing over local 

 irregularities of bark and the tendency to depart from a true 

 horizontal in passing around the tree trunk. 



After trying both calipers and diameter tape, the forester 

 realizes that something better is necessary for general practical 

 use. In the summer of 1908, the writer's attention was called 

 to the Biltmore stick by Supervisor Kirkland of the Snoqualmie 

 National Forest, who furnished him the tracing of a scale to be 

 used on a stick for measuring diameters. How this scale was 

 constructed, whether from diagrams or by use of mathematical 

 formula, was not known. Neither was the proper arm length 

 noted on the scale. An arm length of twenty-six inches was tried 

 and a stick bearing this scale used in reconnaissance work on the 

 Snoqualmie National Forest during the field seasons of 1908 and 

 1909, giving fairly satisfactory results and proving the advantages 



