VOLUMK TAI!LK FOR HKWED RAILROAD TIES 



841 



Most of the trees measured were larch, but sufficient Douglas-fir 

 measurements were obtained to be sure that the results would be ap- 

 plicable to both species. 



The usual measurements were taken. Stumps were cut 14 inches 

 high and the trees measured at d. b. h. and inside the bark at 8-foot 

 intervals to the nearest i/io inch. The length of the piece wasted in 

 the top as compared to the utilization obtained in a sawlog operation ( 8 

 inches in the top) was also recorded. 



The trees were separated into diameter and height classes; for ex- 

 amijle. all trees between 12.6" and 13.5" were classed as 13" trees. 



Fig. I. 



.Mathematical means, smoothed out by curves, were used to build up 

 the tie table. The mininnmi top diameter of the pieces required to 

 make the various grades of ties were determined to be as follows, be- 

 ginning with grade No. i, 8.5", 9.2". 9.9". 10.6". and 11.4". The 

 curves (fig. i) for the 16-inch d. b. h. class will illustrate the method 

 used in arriving at the figures for the volume table. 



Several satisfactory checks have been obtained by comparison of the 

 percentage of ties cut from certain stands as determined by the railroad 

 inspection and the estimated percentage as determined by the use of the 



