178 STANDARD VOLUME TABLES 



2 and 3 inches, outside bark. The same standard apphes to branches. 

 The " merchantable " top diameter for European conifers is about 7 

 centimeters or 3 inches outside bark, but this apphes to wood for manu- 

 facture, and practically the whole tree may be taken by the use of fagots ; 

 i.e., brushwood, done up in bundles. There is considerable range in 

 top diameters even for these purposes, the top diameter limit, and 

 consequently the waste, increasing in regions of poor markets. The 

 top diameters used in constructing tables of merchantable volume 

 must be clearly stated. For peeled wood, diameter inside bark is given. 



The minimum top diameter usually does not coincide with an 

 exact merchantable length, but when a length of 4 feet is used, the 

 practice may be adopted of accepting the last 4-foot stick which measures 

 the minimum diameter at the middle of piece. The average top diameter 

 will then coincide with the minimum established, half the sticks being 

 slightly below this limit at the top end. 



The merchantable top diameter, combined with the minimum length 

 of a merchantable piece, indicates the smallest size of tree measured 

 at B.H. which can be shown in the volume table. Ordinarily, the mini- 

 mum commercial diameter limit will be somewhat larger than this, 

 based on the inclusion of cost of logging as a factor preventing the 

 marketing of trees with the minimum merchantable contents. Volumes 

 of trees of still smaller sizes can be shown only in tables for total cubic 

 volume. Since the merchantable limit of top diameters for cordwood 

 is small, in constructing standard volume tables for cubic feet or cords 

 the trees are classed by D.B.H. and total height, in 5- or 10-foot height 

 classes, as for tables giving total volume. 



148. Stump Heights. Stump height varies with local custom and 

 with the scarcity and value of the wood. Stump heights, especially 

 for large trees, are not uniform but increase with the diameter of the 

 tree, and rules for cutting usually recognize this fact, specifying for 

 instance that the height of stump shall not exceed one-half its diameter. 

 For small timber, uniform stump heights may be specified, as low as 

 from 1 foot to 6 inches. If the stump heights used in constructing the 

 volume table are stated it enables the cruiser not only to know whether 

 the table conforms to local usage, but to correct it for difference in 

 practice. 



The cutting of low stumps not only increases the merchantable 

 contents of the tree but will greatly increase the possibility of error 

 by use of Smalian formula for volume. This error is always plus and 

 will require special measurement of short lengths in butt log. 



149. Merchantable versus Used Length. Where the portion of the 

 tree which is actually used falls short of the full possibility, due to care- 

 less supervision or to failure to appreciate the economic conditions, 



