302 A MANUAL FOR NORTHERN WOODSMEN 
The Forest Service has employed the Biltmore stick in 
measuring large timber on the Pacific Coast and else¬ 
where, and the tests applied have shown reasonable 
accuracy. A careful analysis of sources of error 1 has devel¬ 
oped the following: 
(а) Tilting the stick and holding it other than vertical 
to the line of sight to the trees’ center are practices to be 
guarded against, but if reasonable care is used in manipula¬ 
tion, errors are negligible. 
(б) In applying values derived from plots or tables to 
the stick itself, regard must be had to its thickness. The 
stick may well be beveled, or a steel spline may be inserted 
into it to carry the graduations. 
(c) Errors arising from measuring a tree the narrow or 
the wide way are greater than with the caliper; hence 
cross measures are the more desirable. 
(< d ) It is very easy in practice to vary the distance 
between the stick and the eye, and this introduces error 
that is material, though in continued work successive 
errors tend to balance. 
( e ) Men of ordinary height have a constant tendency 
to measure tree diameter not breast high, but higher, near 
the eye level. 
To conclude, the Biltmore stick requires to be practi¬ 
cally tested before use and constant care in application. 
More liable to error than the caliper, in ordinary timber 
it works less rapidly as well. While serviceable in its 
field, its general use is not to be recommended. 
1 Bruce at previous reference. 
