Measures and yields of products and residues 32o5 



Schnur's graph (fig. 27- 12 A) shows that entire bark-free stems in oak stands 

 averaging 14 inches in dbh contained about 4.6 board feet, Scribner scale, per 

 cubic foot. 



MEAN DIAMETER OF TREES IN 

 STAND, BREAST HIGH (INCHES) 



Figure 27-1 2A. — Ratio of board-foot volume by the Scribner log scale to cubic feet in 

 entire bark-free stems above stump height in stands of upland oaks sampled 

 rangewide. (Drawing after Schnur 1937.) 



Jokela and Lorenz found (fig. 27-12B) that by International '/4-inch scale 

 entire bark-free stems of 14-inch trees in the Sinnissippi National Forest con- 

 tained about 3.4 board feet per cubic foot. The authors noted that the accuracy of 

 the graphed averaged ratios is related to site conditions and their use results in 

 overall board foot estimates 3 percent low for good sites, and 0.3 percent low for 

 medium sites, and 4 percent high for poor sites. 



Hilt's data (fig. 27-12C) on black, chestnut, northern red, scarlet, and white 

 oaks indicate that entire bark-free stems of 14-inch trees sampled in five states 

 contained about 4.6 board feet. International 'A-inch scale, per cubic foot. 



Beck (1964) found that for yellow-poplar, the board-foot/cubic-foot ratio can 

 be computed with the following equation (based on International '/4-inch log 

 scale and cubic volume including bark): 



Bd ft/cu ft ratio = 6.1670 + 8.4641 D/H - 249.2550 1/H (27-40) 



where: 



D = diameter at breast height (inches) 



H = total tree height (feet) 



The equation and table 27- 1 1 3 show that the ratio increases with an increase in 

 both diameter and total height and that diameter has more effect on the ratio than 



