PRACTICE OF TIMBER ESTIMATING 



173 



examining trees as they are felled results as follows: 

 20 normal trees 17 to 20 inches in breast diameter when 

 scaled by the above methods give 4730 feet B. M., while 

 trees of the same dimensions are given in the volume table 

 on page 238 5720 feet. The actual scale, therefore, is 17 

 per cent less than the tabular values. 



24 trees 14 to 16 inches in diameter which by the table 

 should yield 4080 feet scale up 3480, or 15 per cent less. 



30 trees 11 to 13 inches in diameter that by the table 

 should yield 4380 feet, actually scale 3500, or 20 per cent 

 less. 



The figures of the volume table may now be reduced by 

 these percentages in those heights and sizes where on the 

 given job the figures are required. The working table 

 will then be as follows: 



SECTION V 

 PRACTICE OF TIMBER ESTIMATING 



The methods that should be employed in a survey of 

 standing timber depend on a great variety of facts of which 

 the main ones are these: the size of the tract to be ex- 

 amined, the method and fineness of its subdivision, the 

 variety in its stand of timber, the value of the timber, and 

 the experience and qualifications of the estimator. These 

 methods are best discussed in two divisions, first, 

 methods for small tracts with valuable timber as a rule; 

 and second, those for large tracts where more extensive 

 processes must be employed. 



