VOLUME TABLES AND TREE FORM 169 



may for one reason or another be of interest to the worker 

 in timber: 



(a) Near the ground a section taken lengthwise of a 

 tree is concave outward, due to the swell of the roots. 

 Above that, to a point somewhere near the lower limbs of 

 a forest-grown tree, the stem has almost a true taper. 

 From the lower limbs up, the form is roughly conical, with 

 a sharper taper than below, the taper usually increasing 

 toward the top. 



(6) Of two trees having the same breast diameter, the 

 shorter will usually have the larger form factor. This 

 results from the relation just mentioned. Of two trees 

 having the same height, the stouter, more openly grown 

 tree will usually have a little larger form factor than the 

 other. 



(c) Of two trees having the same dimensions, the older 

 one, as a rule, has the larger form factor. The effect of 

 other conditions of growth can seldom be clearly traced. 



(d) Different soft wood species do not differ from one 

 another so greatly but that a volume table made for one 

 may for some purposes be used for others. 



A large form factor in all these cases simply means 

 that the given tree more nearly approaches the form of a 

 cylinder, or, in other words, that it has a large amount of 

 wood for its height and diameter. That carries with it 

 more scale, more sawed lumber, or more cord wood. 



A table giving the contents of trees of stated dimensions 

 is called a Volume Table. For scientific purposes solid 

 content is given, standard measure, but a table may be 

 worked out in cords, board feet, or any other unit required. 

 The tables employed by European foresters at the present 

 day are worked out commonly on the basis not only of 

 height and diameter but of age classes or of some other 

 determining factor, and they have proved to give the con- 

 tents of standing timber very accurately. 



Tables of this kind have also been frequently devised 

 for estimating in this country. Usually these are local, 

 worked out in the timber of the region in question accord- 

 ing to local scaling methods; often also allowing the cull 

 which is found to characterize the region. Such volume 



