3252 Chapter 27 



2. The 168-cu-ft unit of 5-foot 3-inch rough bolts stacked in a rick 4 feet 

 high and 8 feet long. According to Forest Farmers Association (1966), 

 one of these units is equivalent in volume to 1.315 standard cords. 



3. The 200-cu-ft unit of straw-piled rough bolts 5 feet 3 inches long. 



Volume of solid material in a cord. — The solid content (wood and bark) in a 

 standard rough cord is most if the wood is compactly piled, short, well trimmed, 

 straight, and of large diameter (table 27-1). Airspace in a cord of hardwood 

 typically varies from 23 to 53 percent for stemwood and up to 61 percent for 

 topwood. Solid content ranges from 50 cu ft for stacks of small-diameter, 8-foot 

 topwood sticks to 98 cu ft for large-diameter, straight, 4-foot sticks (table 27-1). 

 As an average, 90 cu ft per cord is often used for cords composed of straight 

 sticks (Worley 1958). A study in New York oak stands resulted in an average of 

 85 cu ft per cord (Schnur 1937). However, scrub oak sold for fuel in Texas 

 averaged only 70 cu ft per cord; the sticks were 4 feet long and had a minimum 

 diameter of IVi inches (Baudendistel 1941). 



Often it is preferable to know the volume of bark-free wood in a rough cord. 

 For many years a South-wide average of 79 cu ft per cord was used for hard- 

 woods (Taras 1956). A recent survey of the North Carolina Piedmont (Welch 

 1975) showed an average of 74 cu ft of wood per standard cord of hardwood 

 (table 27-2). 



Wood volume can be easily estimated once the percentage volume of bark is 

 known. Chamberlain and Meyer (1950) list bark volumes (in percent of un- 

 peeled wood) corresponding to the average ratio of diameter inside bark to 

 diameter outside bark (table 27-3). These ratios have been tabulated for the 

 following species: 



Maple, red 



Oak, black 



Oak, chestnut 



Oak, northern red and scarlet 



Oak, white 



For bark volume as a percent of volume of wood and bark in pulpwood piles of 

 four of these species, see table 13-22. 



For ratios of bark volume to stemwood volume in 6-inch trees of 22 species of 

 pine-site hardwoods, see table 13-21, which also relates cubic feet of bark per 

 standard rough cord to the volume of wood, free of bark and voids, contained in 

 the cord. 



In long cords of mixed oaks, bark occupied 12 percent of the stacked volume 

 of unpeeled, straight bolewood and 13 percent of the stacked volume of un- 

 peeled topwood and crooked, knotty bolewood (Barrett et al. 1941), 



The number of standard cords of unpeeled wood needed to make one standard 

 cord or one long cord of peeled wood varies according to the bark thickness of 

 the species cut, as shown in table 27-4. 



Wood volume in long cords of peeled oak was studied in the southern Appala- 

 chians (Barrett et al. 1941). The average wood volume per long cord for straight, 

 split bolewood was found to be 109 cu ft; the range in the 66 stacks measured 

 was 91 to 125 cu ft. The volume of solid wood averaged 93 cu ft and ranged from 



