Chapter 27 



BOARD FOOT SCALING 

 (16' LENGTH) 



TAPER 



5" 



4" 



12 13 14 15 16 17 18 19 20 21 22 

 LOG DIAMETER (INCHES) 



M 146 627 



Figure 27-1 1 . — The effect of log diameter on the absolute yield when logs are scaled by 



conventional board-foot log rules (above the "0" y axis) and on the lumber recovery 



factor (LRF) when the logs are cubically scaled for taper of 1 to 5 inches per 1 6 feet. All 



logs are 16 feet in length (Hallock et al. 1979). 



Most pine-site hardwoods have more taper than the southern pines on which 

 these tables were based; they therefore have more cubic foot content per Mbf log 

 scale than indicated by table 27-112. 



The first four columns of table 27-105 relate tree diameter to cubic foot 

 content and board foot contents as measured by the three principal log scales. 



For upland oaks, the ratio of board foot volume by log scales to entire stem 

 cubic foot volume above stump (excluding bark) have been graphed by three 

 investigators, as follows: 



Reference and sample 

 description 



Schnur (1937) 



Rangewide (404 plots) 



Jokela and Lorenz (1957) 



Illinois; 738 trees 10 to 26 inches 

 in dbh 



Hilt (1980) 



Kentucky, Missouri, Ohio, Indi- 

 ana, and Illinois; 334 trees 2.4 to 

 25.5 inches in dbh 



Basis Log rule 



Ratios for stands of upland oaks for Scribner 



given mean stand diameters 

 "Local ratio table" for upland oak International '/4-inch 



trees in the Sinnissippi National 



Forest; trees were relatively short 

 Based on taper equations for individ- International '/4-inch 



ual trees of various heights 



