CHAPTER XIII 

 VOLUME TABLES FOR BOARD FEET 



153. The Standard or Basis for Board-Foot Volume Tables. In 



Chapter X it was shown that the basis of measurement for standing 

 timber intended for sale is either the possible sawed output for tracts 

 that are cut by local mills, or the log scale for timber to be transported 

 to mills at some distance from the area. Even in the first instance 

 the measurement of tree volumes requires a local log rule based on 

 mill tallies. 



Volume tables for board feet must be based upon the contents of 

 the logs which can be cut from sound trees, as measured by the stand- 

 ard or log rule which forms the basis of sale of the timber. For the 

 purpose of timber estimating for which these tables are required, it 

 is not permissible to substitute volumes representing a different stand- 

 ard even if a more accurate one. 



But it is recognized that existing conditions requiring the scaling 

 of logs by defective log rules may change and for purposes of stock 

 taking or inventory of standing timber required by an owner for the 

 management of forest property which he intends to retain, and for the 

 prediction of growth, volumes of standing timber are preferably meas- 

 ured by tables based on log rules which give an accurate measurement 

 of the board-foot contents of the trees. 



This conflict between a temporary economic condition and a per- 

 manent basis of management may require a double standard of measure- 

 ment, and two separate volume tables. The first step in the con- 

 struction of volume tables for board feet is to decide upon the log rule 

 to be used in obtaining the tree volumes. 



For second-growth timber, and for the purpose of inventory and 

 basis of growth studies, this should if possible be a rule such as the 

 International, or one based on mill tallies of lumber such as the Massa- 

 chusetts log rule. 



For commercial timber estimating it must of necessity at present 

 be the log rule in common use in the locality. 



154. Adoption of a Standard Log Length. The standard practice, 

 in measuring the contents of entire trees for the construction of board- 

 foot volume tables is to disregard the actual log lengths as sawed, and 

 to measure the diameter on the bole at fixed points corresponding to 



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