VOLUME TABLES AND TREE FORM 167 



Example : Standing 80 feet from a tree, the angle to the top is 

 found to be 31 and that to the base 8} , of depression. From the 

 tables the tangent of 31 is found to be .6009 ; multiplying this by 

 80 gives 48 feet for the height of the tree above the level of the eye. 

 Again the tangent of 8J is found from the tables to be .1495 and 

 this multiplied by 80 gives 12 feet. 48 + 12 = 60 feet, the total 

 height of the tree. 



6. Faustmann's height measure works in much the 

 same manner, but gives the desired height directly without 

 the use of tables. This instrument may be had of dealers 

 at a cost of from $6.50 up. It is compact, not complicated, 

 and will be found of great service in estimating. 



SECTION IV 

 VOLUME TABLES AND TREE FORM 



A competent woodsman can tell from the looks of a 

 tree somewhere near what it will scale, saw out, or yield 

 in cord wood according to the practice with which he is 

 familiar, and this without any measurements. Or a 

 caliper may be used instead of the eye for diameter, and 

 some kind of determination made of the height of the 

 tree or the length and size of the logs into which it may 

 be cut. The point of such judgment and measurements 

 as a rule is their wider application. The single tree so 

 examined is taken as the type of many, and the stand of 

 an acre or of a considerable territory is thus estimated. 



In this process the assumption is made that trees of the 

 same dimensions are approximately similar in shape, 

 while for the individual tree the fundamental factors de- 

 termining contents are recognized as height and diameter. 

 These two factors in any kind of timber work cannot 

 possibly be disregarded. Whatever the scaling or mill 

 practice of a locality may be, and into whatever form a 

 tree's trunk is dissected before manufacture, the height of 

 the tree and its diameter at some point near the base are 

 the chief factors determining contents. These factors, 

 consciously or unconsciously, are in the mind of every 

 estimator. 



Scientific study of tree form began by making the same 

 assumption and selecting the same factors. While it 



