Solid Wood Products 269 1 



Table 22-28 — Grade yields of boards and studs by percentage of volume for small 8- 

 foot-long yellow-poplar logs sawn by three methods to two thicknesses (Maeglin et al. 



1981) 



Board thickness, sawing method, 



and lumber grade Yield 



Percent 



II A studs by SDR method 



Stud 99 



Economy 1 



7/4 study by CON method 



Stud 88 



Economy 12 



4/4 boards by cant method 



Select 



IC 2 



2A 18 



2B 36 



3C 44 



Harpole et al. (1979) analyzed the economics of carrying the SDR idea one 

 step further, i.e., to live saw 8/4 flitches, from 8- to 12-inch logs, edge them to 

 fullest possible width, edge glue them into wide panels, and then rip the wide 

 panels to desired width for structural joists and planks. This is a variation of a 

 technology that was very widely practiced by the white pine (Pinus strobus L.) 

 wood box industry of New England in the 1930's and 1940's. Harpole et al. 

 found that this system, used to increase the amount of wide- width dimension 

 lumber (2- by 10-inch and wider), yielded a 12- to 13-percent increase in volume 

 over more conventional sawing procedures and justified the additional invest- 

 ment required. 



See also sections 28-12 and 28-22 for summaries of economic feasibility 

 studies of structural-lumber manufacture from yellow-poplar. 



Research suggests that straight, dry, well-manufactured yellow-poplar struc- 

 tural lumber, if available at competitive prices, is potentially acceptable to 

 lumber users. Schick (1978) and Schick and Grinell (1979) found that in West 

 Virginia, lumber wholesalers, retailers, homebuilders, and architects responded 

 positively toward potential distribution and use of yellow-poplar framing lum- 

 ber, but with some important reservations. Recent acceptance by the American 

 Lumber Standards Committee of the structural grading rules for yellow-poplar 

 proposed by the Northern Hardwood and Pine Manufacturing Association 

 (1978) should overcome one major problem. Inclusion of such lumber in promo- 

 tions of the National Forest Products Association, and acceptance by the various 

 regional and local building codes should clear the way for wide acceptance of 

 yellow-poplar framing lumber. 



Other hardwood structural grading rules accepted by the American Lumber 

 Standards Committee are for cottonwood (Populus deltoides Bartr. ex Marsh), 

 aspen {Populus tremuloides Michx.), and red alder (Alnus rubra Bong.). Read- 

 ers interested in the procedure whereby stress-graded structural lumber achieves 



