PRACTICE OF TIMBER ESTIMATING 183 



in small bodies of timber and in tracts of sm.-ill dimensions. 

 This is because a man can really see and grasp them. 

 Such estimates are particularly useful for timber of small 

 value or in very bunchy and irregular woods, which it is 

 hard to survey. In such circumstances the judgment of a 

 good woodsman is sometimes the best valuation that is 

 practicable. 



The ability to estimate timber after this fashion is gained 

 by practice, and is based on personal experience and ca- 

 pacity ; consequently each man goes about it in a way of his 

 own. To know the area of the tract in question is generally 

 of great assistance, and most men will be continually study- 

 ing the matter of average stand per acre. As a prelimi- 

 nary step in arriving at this it is generally desirable to settle 

 maximum and minimum stand as well. 



For the contents of single trees a woodsman may rely 

 on a mere glance, or he may figure carefully. A northern 

 Maine lumberman, for instance, looking at a fair-sized 

 spruce might estimate that it will cut a log 10 inches in 

 diameter at the top and 30 feet long, and such a log he 

 might know will measure 180 feet in local scaling prac- 

 tice. Again, in regions where logs are cut short, and 

 several are taken from a good-sized tree, men frequently 

 jot down the estimated contents of the several logs and 

 add up the figures to get the tree's total contents. Using 

 such methods to get at the size of the trees, lumbermen 

 then go on, in one way or another, to get the contents of 

 bodies of timber or stand per acre. 



Frequently, however, the impression gained is a direct 

 one, of quantity on a whole tract or of constituent bunches. 

 A man cannot tell just how such figures come into his 

 mind, but they do arise there, dependent somehow on his 

 experience, perhaps in laying out roads or chopping timber. 

 Such training is effective, and when the judgment arising 

 as a result of it has been actually tested and found suffi- 

 ciently close and reliable for any given purpose, it would be 

 folly not to use it. But every one knows that such judg- 

 ments are fallible, as in the nature of the case they could 

 not fail to be. Differences in size and height may escape 

 a man if the stands traversed look generally alike; the 



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