DETERMINING THE QUALITY OF STANDING TIMBER 



By Swift Berry 



Forest Examiner, Forest Service 



The quality of the stand, as measured by the grades of lumber it 

 will produce, is one of the most important factors entering into the 

 appraisal of the stumpage value of a timber tract. In appraisals of 

 National Forest timber the stumpage value is considered to be the 

 difference between the estimated average selling price and the sum of 

 the estimated cost of production and the- assumed margin of profit. 

 Since the average selling price per thousand for each species depends 

 upon the proportion of the grades in the product, a mistake in estimat- 

 ing the quality of the stand may more seriously aiifect the accuracy of 

 an appraisal than any possible error in calculating the operating cost. 

 Thus there is plainly need for exact and uniform methods of deter- 

 mining the quality of stands involved in stumpage appraisals. In this 

 connection, the method now used in District 5 may be of interest. 



The first action in obtaining material for use in estimating the grades 

 that may be produced from logs or standing timber is the making of 

 mill-scale studies to record the grades actually cut from the various 

 species in different localities. In order to facilitate the arrangement 

 of the data resulting from this work, tentative log grades were estab- 

 lished and rules prepared outlining the specifications of these grades. 

 Three grades were made for both sugar and yellow pine, each being 

 based upon the prevailing lumber grades in the logs within it. Thus 

 grade I logs cut largely to clear lumber, grade II logs to shop lumber, 

 and grade III logs to common and box lumber. Douglas fir was also 

 given three log grades, but only two were made for white fir and 

 incense cedar. 



In carrying on the mill-scale studies, the logs are scaled and graded 

 and a record kept of the amount and grades of lumber sawed from each 

 log. At the end of the study the results for each species are compiled 

 into tables, showing the average amounts and per cents of lumber by 

 grades sawed from logs of each inch diameter class under each log 

 grade. The per cents are then adjusted by curving into tables for field 

 use. An example of such a table is given here as Table 1 : 



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