46 



STATE BOARD OF FORESTRY. 



TABLE 3. (A transformation of Table 2.) Average volume in board 

 feet, as shown by the Ropp Log Rule, contained in merchantable por- 

 tion of immature western yellow pine trees of different merchantable 

 lengths and diameters breasthigh. 



TABLE 3. 



This table was obtained by transforming the values in Table 2, based 

 on the Spaulding Log Rule, to values shown here based upon the Ropp 

 rule. The transformation was made in accordance with the underlying 

 principles of both rules, and was accomplished as follows : To each value 

 shown in Table 2 twice the merchantable length indicated at top of 

 table was added. The new values thus obtained were divided by 

 (1 .266) and multiplied by (1 .236) , and three times the merchant- 

 able length subtracted. The resulting table is based upon the Ropp 

 rule, and does not include any logs under 10" in diameter, since logs 

 below this size have been automatically discarded by the Ropp rule 

 formula, which gives small negative results for logs under 8" and small 

 positive results for logs between 8" and 10". The negatives below 8" 

 and the positives between an 8" and 10" will about neutralize, thus 

 giving a table which does not include logs below 10" in diameter. 



