104 LOG SCALING FOR BOARD MEASURE 



log. The fact that, with increasing prices unsound lumber is sold and 

 is graded does not change the standard scaling practice, which takes 

 no account of these unsound grades and excludes them from the scale. 

 Such lumber merely increases the amount of the over-run. 



The characteristic sound defects are tight or sound knots, pitch 

 and stain. Sound tight knots never reduce the. scale unless present in 

 such size and quantity as to cause the lumber to fall apart or to be 

 rejected. Stained sap, which is still firm, or red heart, the precursor 

 of red rot, are scaled. Pitch is usually classed as a sound defect for 

 which no deduction in scale is made. But these defects, especially 

 knots, and others such as twisted grain and wide rings do serve to reduce 

 the grade of the log. The presence of unsound defects, such as rot, 

 shake and break, does not reduce the grade of a log, provided there is 

 sufficient sound lumber remaining to permit the log to meet the mini- 

 mum requirements of the grade. Since the purpose of log grades 

 is to establish value, log grading specifications are drawn so as to permit 

 logs of the same average value to be placed in the same grade, and too 

 detailed specifications are avoided. 



By thus simplifying the classification of logs by grade, the total 

 log scale is easily separated into log grades, and any variation in the 

 average quality of logs within the grade can be adjusted in the price 

 of the grade (§359). 



For any given region, and class of timber, the actual average per 

 cents of different standard grades of lumber contained in log grades 

 can then be determined by mill-grade or mill-scale studies (§ 361). 

 These per cents can then be applied to the total scale for each log grade 

 with far greater accuracy than could be attained by attempting to ana- 

 lyze the scale of each log. 



Log grades, as analyzed by such mill-grade studies, have become the 

 basis of determining the stumpage value of standing timber in appraisals 

 as conducted by the U. S. Forest Service (§ 234). 



References 



Cost of Logging Large and Small Timber, W. W. Ashe, Forestry Quarterly, Vol. XIV, 



1916, p. 441. 

 Cost of Logging Small Timber, R. D. Forbes, American Lumberman, Nov. 15, 



1919, p. 52. 

 Cost of Cutting Large and Small Timber, W. W. Ashe and R. C. Hall, Southern 



Lumberman, Deo. 16, 1916. 

 Inland Empire Sawing and Skidding Studies, J. W. Girard, Timberman, September, 



1920. 



