in other regions of the United States following the appearance of the 

 first publications, and in each instance sampling saved scaling time 

 and gave acceptably accurate results. Employing the techniques 

 learned in sample log scaling, the system was extended to sampling 

 in tree measurement and it was found applicable to large sales in 

 the Rocky Mountain and Southwestern Regions. (9_) 



The purpose of the present study v;as to apply sample tree measurement 

 to the tree species and conditions found in the Northern Region 

 (Montana, north Idaho, and northeast Washington) « Emphasis v;as to 

 be placed on the three kinds of trees most commonly tree measured 

 in this region — ponderosa pine, Douglas-fir, and western larch. 

 Sampling intensities and techniques necessary for reliable estimates 

 of volumes v;ere to be studied for these species and for the range 

 in timber sizes, defect conditions, and number of trees in sales 

 that are commonly encountered » Stratified sampling was to be investi- 

 gated to determine if sample sizes could be reduced without sacri- 

 ficing accuracy. 



SAMPLE LOG SCALING 



Earlier studies have proved that a batch of 80,000 logs can be scaled 

 with an accuracy of 2|- percent by actually measuring only 4;, 000 logs.{7_) 

 If three percent were considered a satisfactory accuracy, 300,000 

 logs can be scaled by measuring only one out of every 100. As the. 

 number of logs to be scaled increased, the relative size of the 

 sample decreases, but for any sale size above 5,000 logs, sampling 

 saves time and gives acceptably accurate estimates. Furthermore, 

 uniform sampling rates can be applied to logs of all sizes. 



Another report (4_) has described a process of sample scaling that 

 could be applied to west coast logs v/here the range in log size was 

 even greater than in the logs of the Rocky Mountains and southwest. 

 The west coast log report included a table v/hich shov/ed the general 

 range of sampling accuracies proposed for logs of varying defect 

 conditions and stumpage value. 



Sampling methods have been tested on northern Rocky Mountain logs, 

 many of which are in double log lengths, and found applicable with 

 some minor adjustments in sample size to provide for the greater 

 range in volume of long logs. (12_) In eastern Canada, investigations 

 of sample scaling small logs and cordwood bolts ranging in length 

 from 4 to 16 feet showed that san^ding was practicable. (5_) A study 

 in the Lake States {6_) revealed similar results. 



Successful sample log scaling requires a relatively large number 

 of logs in decks, or in a mill pond, or in a hot logging operation 

 to make it cheaper than scaling every log. The method is simple. 

 After the sampling intensity is decided, the scaler counts all logs 



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