Diameter Classifications 



Diameter at breast height (d. b. h.). — Diameter, out- 

 side bark, measured at 4.5 feet above average ground 

 level. 



Diameter class. — Trees were recorded in 2-inch diam- 

 eter classes, each class including all trees measuring 

 1.0 inches below and 0.9 inches above the midpoint 

 of the class. For example, the 6-inch class included 

 all trees whose d. b. h. fell in the range of 5.0 inches to 

 6.9 inches inclusive. 



Forest Conditions 



Saw-timber stands. — Stands of 10 acres or larger, each 

 acre of which bears a minimum volume of 2,000 board 

 feet. Saw-timber volume is measured in conifers 9.0 

 inches d. b. h. and over and in hardwoods 11.0 

 inches d. b. h. and over. 



Pole-timber stands. — Stands of 10 acres or larger, each 

 acre of which bears a minimum of 5 standard cords in 

 trees 5.0 inches d. b. h. and over and less than 2,000 

 board feet of saw timber. 



Unmerchantable stands. — Young-growth areas of forest 

 land that have less than 5 standard cords of wood on 

 each acre in the trees 5.0 inches d. b. h. and over, 

 plus saw-timber and pole-timber stands that are less 

 than 10 acres in extent. 



Volume Estimates 



Saw-timber volume. — The saw-timber portion of saw- 

 log-size trees. Top diameters vary with the limits of 

 usable material. The International %-inch log rule 

 (derived from the formula V = 0.796D 2 — 1.375D — 

 1.230) was used. Board-foot volumes so derived 

 closely approximate green lumber tally. Deductions 

 were made for cull. 



Cubic-foot volume. — The gross volume, including bark, 

 of all trees 5.0 inches d. b. h. and over. This em- 

 braces the following: 



1 . The sawlog portion of sawlog-size trees. 



2. The limbs and tops of sawlog-size trees to an 

 approximate 4-inch diameter. 



3. The full stems to an approximate 4-inch top 

 diameter of trees under sawlog size. 



Cordwood volume. — This volume was derived from the 

 cubic-foot volume by applying a factor of 85 cubic 

 feet per cord for conifers and 75 cubic feet per cord 

 for hardwoods. The standard cord (4 feet by 4 feet by 

 8 feet) was the unit of volume measurement used. 



Tons. — The total cubic-foot volume was converted 

 to short tons (green weight) by applying average cubic- 

 feet-per-ton factors to the volumes of the various 

 species groups. These factors were: 46.3 for the I 

 conifer group; 32.9 for the oaks, hickory, and sugar 

 maple group; and 38.2 for the other hardwoods group. 



Growth 



Growing stock.— The sum of the total volumes of all 

 sound, living trees 5.0 inches d. b. h. and larger. 



Forest increment. — The net increase in volume of 

 wood produced on the growing stock after allowance 

 for normal losses due to wind, insects, disease, and 

 crowding; for the merchantable forest it includes the 

 volume of stands attaining the requirements of each 

 class during the year. 



Drain 



Commodity drain. — The volume of material utilized 

 from trees 5.0 inches d. b. h. and larger plus measur- 

 able volume in felled trees left unutilized. 



Drain due to fire. — The volume of material in trees 

 5.0 inches d. b. h. and larger destroyed by fire. 



1 ree Species 

 Softwoods 



Lumber or trade name 

 Cedar, red 

 Cedar, white 

 Hemlock 

 Pine, southern yellow 



Pine, white 



Spruce, eastern 



Recognized common name 

 Eastern red cedar 

 Northern white-cedar 

 Eastern hemlock 

 Pitch pine 

 Virginia pine 

 Eastern white pine 

 Red pine 

 Black spruce 

 Red spruce 



Botanical name 

 Jumperus virginiana 

 Thuja occidentalis 

 Tsuga canadensis 

 Pinus rigida 

 P. virginiana 

 P. strobus 

 P. resinosa 

 Picea mariana 

 P. rubens 



58 



Miscellaneous Publication 648, U. S. Department of Agriculture 



