Measures and yields of products and residues 3329 



A study in the Missouri Ozarks (Massengale 1971) produced information on 

 the weight yield of green slabs and edgings from 8-foot logs of mixed oaks. The 

 range was from 1 ,790 pounds per Mbf Doyle scale for 16-inch-diameter logs to 

 4,155 pounds for 9-inch logs (table 27-144). Each log was sawn for maximum 

 yield of 4/4 lumber, and the solid-toothed saw had a 3/16-inch kerf. 



Slab yield per Mbf lumber scale. — Eight-foot-long mixed oak logs from the 

 Missouri Ozarks produced from 1,530 to 3,300 pounds of green slabs and 

 edgings per Mbf of lumber sawn (table 27-145). 



With yellow-poplar, the green weight of chippable residues (slabs, edgings, 

 and end trim) per board foot of lumber decreased as tree size increased (Clark et 

 al. 1974). In this study, 47 yellow-poplar trees 12 to 28 inches in dbh were 

 bucked into 8- to 16-foot logs, debarked, and sawn into 4/4 lumber on a bandsw. 

 Weight of chips per board foot of lumber ranged from 3.0 pounds for the 1 2-inch 

 trees to 1 .4 pounds for the 28-inch trees and averaged 1 .6 pounds (table 27-100). 



Slab yield per log or tree. — Tables 27-142 and 27-143 give cubic-foot yields 

 of slabs and edgings from logs 6 to 20 inches in diameter and 8 to 16 feet long. 

 These estimates were developed by Bennett and Lloyd (1974) by an extension of 

 the International 14-inch and Scribner log rules. The authors caution that slab 

 and edging estimates based on the International V4-inch rule represent the mini- 

 mum to expect; they apply if the logs are bucked into lengths that eliminate most 

 of the sweep and crook and are carefully and properly sawn. 



Tables 18-57 through 18-62 tally predicted cubic-foot yields of chippable 

 residues from 10 to 24-inch-diameter trees in six species: red maple, black oak, 

 chestnut oak, northern red oak, white oak, and yellow-poplar. In this study by 

 Hanks (1977) sawmill residue volume was defined as the cubic-foot volume of a 

 tree — including rot and voids — that reaches the mill and is not converted to 

 lumber or sawdust. Most of this residue is suitable for pulp chips, but 2 to 4 

 percent is not usable because of rot (see page 1954). 



In Massengale 's (1971) study of mixed oak logs from the Missouri Ozarks, he 

 projected the average weight of green slabs and edgings per log — ranging from 

 34 pounds for 8-inch-diameter logs 8 feet long to 347 pounds for 16-inch- 

 diameter logs 16 feet long (table 27-146). 



Chippable residues (slabs, edgings, and end trim) accounted for an average of 

 20 percent of the green weight of black oak saw logs processed in western North 

 Carolina (Phillips 1975). As scaling diameter increased, chippable residue de- 

 creased, ranging from 25.6 percent of small-diameter logs to only 16.4 percent 

 of large-diameter logs (table 27-147). In this study, 130 sample logs were cut 

 from 40 trees 12 to 26 inches in dbh, bucked into logs 8 to 16 feet long with a 

 minimum scaling diameter of 8 inches inside bark, and debarked with a rosser- 

 head debarker. Logs were sawn in a mill with a thin-kerf band headsaw, an in- 

 line edger, and end-trim saws for maximum grade yield of 4/4 and 5/4 lumber. 

 Predicted residue yields are given by log diameter and log length in table 27-148 

 and by tree dbh and merchantable height in table 27-149. 



A comparable study with yellow-poplar (Clark et al. 1974; Clark 1976) 

 showed that 18 percent of the saw log green weight ends up as chippable residue. 

 As in the black oak study, the yield of chippable residue decreased with increas- 



