A collection of log rules

Abstract

A log rule may be defined as a table or formula showing the estimated net yield for logs of a given diameter and length. Ordinarily the yield is expressed in terms of board feet of finished lumber, though a few rules give the cubic volume of the log or some fraction of it. Built into each log rule are allowances for losses due to such things as slabs, saw kerf, edgings, and shrinkage. At first glance, it would seem to be a relatively simple matter to devise such a rule and having done so that should be the end of the problem. But it would seem so only to those who are unfamiliar with the great variations in the dimensions of lumber which may be produced from a log, with variations in the equipment used in producing this lumber and the skills of various operators, and finally, with the variations in the logs. All of these have an effect on the portion of the total log volume that ends up as usable lumber and the portion that becomes milling residue. Historically the lumber industry has consisted of a number of independent marketing areas or even of separate companies. Since no industrial organization or government agency had control over the measurement of logs, each district or even individual buyers could devise a rule to fit a particular set of operating conditions. The result is that in the United States and Canada there are over 95 recognized rules bearing about 185 names. In addition, there are numerous local variations in the application of any given rule.

Citation

Freese, Frank. 1973. A collection of log rules. Gen. Tech. Rep. FPL-01. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 65 p.