CHAPTER XIX 



PRINCIPLES UNDERLYING THE ESTIMATION OF STANDING 

 TIMBER 



205. Factors Determining the Methods Used in Timber Estimating. 



There are five basic considerations which determine the conditions 

 and methods to be used in estimating timber. These are: 



1. The form of product in which the volume of the timber is to 

 be estimated. This determines the unit of volume to be used, as the 

 piece (poles, railroad ties), the board foot for saw timber, and the cord 

 for bulk products (§§9-12). 



2. The economic conditions, customs and usages governing tht> 

 business of logging and lumbering. These determine the basis on 

 which standing timber is to be sold and the place and form in which 

 it is to be measured. The three considerations which affect the work 

 are, whether the basis of volume measurements is to be the contents 

 of logs or the sawed output in the form of lumber, what log rule is to 

 be used in scaling the logs, and the practice of scaling as to log lengths, 

 diameters and cull as affecting the scaled contents of the timber 

 (§§ 81-83). 



3. The character of the demand for timber products and the result- 

 ant closeness of utilization of the trees in the stand. This will determine 

 the top diameters and stump heights to which the timber must be esti- 

 mated, and the minimum D.B.H. (diameter limit) of trees to be esti- 

 mated as part of the merchantable stand, and consequently the per cent 

 of the total cubic volume of the stand which is estimated as merchant- 

 able (§23). 



4. The available volume tables, their reliability and basis of numbers, 

 their method of construction, their basis of diameter, height and mer- 

 chantable top diameters (§ 124). This will determine, 



(a) Whether to dispense with a volume table and substitute a 



log rule, tallying the contents of the trees in the form of 

 separate logs or to depend upon a volume table for entire 

 trees. 



(b) The point at which diameter must be measured in timber 



estimated, as stump, D.B.H. , or top of first log inside 

 bark. 



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