CHAPTER XII 



STANDARD VOLUME TABLES FOR MERCHANTABLE CUBIC 

 VOLUME AND CORDS 



145. Purpose and Derivation of Tables for Cubic Volume of Trees. 



Volume tables for merchantable cubic volume are intended to measure 

 the merchantable portion of trees, thus excluding the stump, top and 

 branches too small for use. In America these tables are used for the 

 measurement of firewood, pulp or acid wood, or products to be totally- 

 consumed or disintegrated (§ 18). The volumes in this class of tables 

 may be obtained from those for total cubic volume by subtracting 

 the waste or unused portion of the stem represented by stump and 

 top, or the merchantable portion of the bole may be computed directly. 

 For board contents or other units, different tables are employed. 



146. Branch-wood or Lapwood. Where branch-wood is of sufficient 

 size for use, which occurs with many hardwoods used for firewood, its 

 volume is computed separately from the stem, usually in 4-foot lengths, 

 each of which is calipered at the center of the stick (by Huber's formula) . 

 The additional volume of branches is termed lapwood. The better 

 method is to keep this volume separate from that of the main bole 

 in the volume table, and express it by diameter classes as a per cent 

 to be added to the volumes in the table. Lapwood is an exceedingly 

 variable quantity, chiefly found in hardwoods, practically absent in 

 conifers, and dependent entirely upon the degree of density of the stand, 

 which also affects the form of the bole itself. Where lapwood is included 

 with the volume of the bole, the trees should be separated not only by 

 diameter but by crown classes, dependent on the degree of crowding 

 and the relative spread of crowns. No more than three such classes 

 would be practical, namely open-grown or large spreading crowns 

 containing a large per cent of merchantable lapwood, medium crowns 

 containing an appreciable quantity of lapwood, and trees without 

 lapwood in quantity sufficient to affect the estimates. 



Standard volume tables (§140) will seldom include lapwood but will 

 be confined to the volume of the main stem. Where lapwood is included, 

 the tables will usually be local in character, and based solely on diam- 

 eter, with a separate table for each crown class. 



147. Merchantable Limit in Tops and at D.B.H. Where cubic 

 volume is utilized,, the limit of merchantable size in the tops lies between 



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