R KG ION A I, VOIyUME TABLE 



733 



mit either ready comparison I)et\veen tables or easy checking of any 

 given table.' The employment of varying standards of utilization 

 alone is an almost insurmountable obstacle to either.^ 



It was with this doubt in mind that a critical analysis ^ of the 

 standard Forest Service white fir (A. concolor) volume table for 

 California was undertaken, a study which resulted in the prepara- 

 tion of three new tables. In the course thereof a number of points 

 came up which seem to have a bearing on the general problem of 

 volume table preparation and of the specific question already men- 

 tioned. 



A CHECK OE THE EXISTING TABLE 



The table under consideration (published in loose leaf form as 

 Form 874 nn.) is based on 1,143 trees from the Plumas, Sierra, Stan- 

 islaus, and Tahoe National Forests. It is commonly used, however, for 

 all other Forests in California where white fir is found. Its chief 

 drawback aside from the possibility that it covers too wide a region, 

 is that heights are taken to a variable top cutting limit ranging 

 from 9 to 15 inches, d. i. b. 



This table was checked against its own basic tree measurements, ^ 

 with the following results : 



Tabi^e 1. — A Check of Forest Service Standard Volume Table for White Fir. 



Number of 

 trees 



Scaled 

 volume 



Volume by 

 table 



Aggregate 

 difference, 

 pe.- cent 



Average 

 deviation, 

 per cent 



Stanislaus (1911) 



Stanislaus (1909) 



Stanislaus (other) . . . 



Sierra 



(Sequoia 



Tahoe 



Plumas 



(Lassen 



(Shasta 



Totals and averages.. 



468 



436 



20 



50 



6 



40 



88 



6 



34 



96,186 



119,762 



3,917 



17,510 



572 



8,683 



14,305 



977 

 1,058 



103,673 



117,191 



3,515 



11,395 



512 



9,211 



16,860 



1,232 



1,036 



264,118 



264,625 



— 7.4 

 -f 2.2 

 -i-11.4 

 +53.6 

 -j-11.7 



— 5.7 

 —15.2 

 —20.7 

 + 2.8 



.19 



13.9 

 13.9 

 14.4 

 54.7 

 25.3) 

 15.5 

 19.4 

 21.0) 

 18.2) 



16.5 



"■ The writer has already enlarged on this point in "The Height and Diameter 

 Basis for Volume Tables," Journal of Forestry, Vol. 18, No. 5, p. 549 f . f. 



^Acknowledgment is made to officers of District Five, U. S. F. S., for assist- 

 ance, encouragement, and helpful criticism in this work. 



''The method of checking was that described by the writer in "A Proposed 

 Standardization of the Checking of Volume Tables," Journal of Forestry, Vol. 

 18, No. 5, p. 544 f . f. 



