3268 



Chapter 27 



10 



20 



30 40 



50 



60 



70 



80 90 



100 



TOTAL AGE (YEARS) 



Figure 27-5. — Yield of wood in entire stems per fully stocked acre of upland oaks, in 

 cubic feet excluding bark, showing trends with age and 50-year site index (SI). (Draw- 

 ing after Schnur 1937.) 



THE POUND 



While the weight of a cubic foot of wood varies with its moisture content 

 (sect. 8-1), ovendry extractive-free specific gravity (ch. 7), and extractive con- 

 tent (sec. 6-6), gross weight is for loggers and many wood users a convenient 

 and equitable measure of value. Conversion of weights to a conventional volume 

 measurement is difficult both because of this variation and because the irregular- 

 ity of tree sections makes volume calculation difficult. 



Weight of a standard rough cord. — Table 7-1 shows the weight of a cubic 

 foot of wood as a function of specific gravity and moisture content. Table 8-2 

 gives an estimate of tree moisture contents by species, and tables 7-6 and 7-7 

 unextracted tree specific gravity by species. Table 7-2 A gives the weight per 



