CONVERTING FACTORS 



George F. Burks 



In dealing with timber volume or volume of 

 different timber products, three types of convert- 

 ing factors are commonly used: (1) Forest re- 

 source factors to convert inventory volume from 

 one unit of measurement to another such as board- 

 feet to cubic feet, and cubic feet to cords; (2) 

 roundwood factors to convert board -foot volumes 

 of logs and bolts measured by a given log rule to 

 equivalent volume by another, or to convert 

 quantity units such as pieces to cubic feet, exclud- 

 ing bark, cords, or board-feet; and (3) utilization 

 factors to show volume of growing stock (live 

 sawtimber and poletimber trees) cut per unit of 

 output of various timber products. 



The three sets of converting factors presented 

 here are applicable on a sectional or broad regional 

 basis and denote average relationships derived 

 from the factors in use in different parts of the 

 country. 



FOREST RESOURCE FACTORS 



Forest resource factors compare (a) inventory 

 volume in board-feet by the International JHnch 

 log rule for sawtimber trees with the corresponding 

 cubic-foot volume, less bark, including both the 

 saw-log and upper-stem portions, and (b) the cubic 

 foot-cord relationships applicable to total growing 

 stock consisting of live sawtimber and poletimber 

 trees. 



Sawtimber 



Cubic feet per M board-feet 

 International M-inch log rule 



All species Softwood Hardwood 



North 219 241 213 



South 205 195 216 



West 171 170 219 



Continental United States... 184 176 215 



Growing Stock 



Cubic feet per cord 

 All species Softwood Hardwood 



North 76 79 75 



South 71 74 69 



Average East 73 75 72 



ROUNDWOOD FACTORS 



Roundwood factors compare the various round 

 timber products in units of measure as customarily 

 reported by the Bureau of the Census, the trade, 

 and other sources with the corresponding round- 

 wood volumes of the logs or bolts from which the 

 product came, expressed in (a) board-feet Inter- 

 national J^-inch log scale, (b) cubic feet excluding 

 bark, and (c) standard cords (128 cubic feet) 

 including bark. They apply to all logs and bolts 

 used for particular products whether the trees from 

 which they were cut were live or dead, classed as 

 culls, or from commercial forest, noncommercial 

 forest, or nonforest land. 



All the various products, except hewn ties, 

 are originally reported as either logs, bolts, cord- 

 wood, or other round timber, but their volume is 

 given in different units of measure. Thus appro- 

 priate converting factors are needed to translate 

 these various volumes in common units to stand- 

 ard units of measure so that any one may be prop- 

 erly compared with any other, or that all may be 

 combined and treated as a group. Saw logs for 

 lumber, for example, are commonly reported in 

 board-feet lumber tally, whereas veneer logs and 

 bolts and cooperage logs and bolts are reported in 

 board-feet log scale according to various log rules — 

 Doyle, Scribner, Spaulding — depending on local 

 practice. Pulpwood and fuelwood statistics com- 

 monly are reported in standard rough cords (128 

 cubic feet), poles, posts, and hewn ties in number 

 of pieces, piling in linear feet, and mine timbers 

 and miscellaneous round timbers in cubic feet. 



Saw Logs, Veneer Logs and Bolts, 

 AND Cooperage Logs and Bolts 



Board-feet International 'A-incli log 

 rule per M board-feet lumber tally 



Saw logs: All species Softwood Hardwood 



North 937 927 943 



South 994 984 1,014 



West 967 968 872 



Continental United States. 973 970 983 



641 



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